{"Bibliographic":{"Title":"Program of research and monitoring for early detection of stratospheric ozone change : report to Congress of findings for 1980-1981","Authors":"","Publication date":"1982","Publisher":""},"Administrative":{"Date created":"08-16-2023","Language":"English","Rights":"CC 0","Size":"0000122900"},"Pages":["QC\n879.7\n.U5\n1982\nReport to Congress of Findings for 1980 - 1981\nA\nOF\nCOMMUNITY\nProgram of Research\nand Monitoring for\nwith\nEarly Detection of\nSTATES\nOF\nStratospheric Ozone\nChange\nWashington, D.C.\nJanuary 1982\nU.S. DEPARTMENT OF COMMERCE\nNational Oceanic and Atmospheric Administration","879.7\nU5\n1982\nReport to Congress of Findings for 1980 - 1981\nProgram of Research\nATMOSPHERIC\nAND\nbetween\nNOAA\nand Monitoring for\nUS EDECARTMENT OF\nEarly Detection of\nStratospheric Ozone\nChange\nJanuary 1982\nLIBRARY\nJAN 2 6 1990\nof\nCommerce\nU.S. DEPARTMENT OF COMMERCE\nMalcolm Baldrige, Secretary\nNational Oceanic and Atmospheric Administration\nJohn V. Byrne, Administrator","Report to Congress of Findings for 1980-81\nTable of Contents\nPage\nINTRODUCTION\n1\nBACKGROUND\n3\nSUMMARY OF FINDINGS\n5\nAERONOMY LABORATORY\n10\nI. Model Calculations\n10\nA.\nSteady-State Depletion of Total Ozone Abundance\ndue to Chlorofluoromethane Emissions\nB.\nThe Origin of Tropospheric Ozone\nC.\nEffects of Particle Precipitation Events\nD.\nCoupled Radiative and Chemical Models\nE.\nComparison of Theoretical and Measured Values\nII. Stratospheric Water Vapor Measurements\n14\nIII. In Situ Stratospheric Composition Measurements\n17\nIV. Laboratory Kinetics Measurements\n17\nV. Remote Spectroscopic Measurements\n20\nVI. Atmospheric Dynamics Measurements\n23\nAIR RESOURCES LABORATORY\n26\nI. Stratospheric Temperature Monitoring\n26\nII. Ozone Monitoring\n26\nA.\nTrend Analysis of Data from the Global Ground-\nbased Ozone Monitoring Network\nB.\nU.S. Dobson Spectrophotometer Ozone Monitoring\nC.\nUpgrading the Global Dobson Spectrophotometer\nNetwork\nD.\nDisparities between Satellite-based and Ground-\nbased Total Ozone Measurements\nE.\nThe Short Umkehr Ozone Profile Technique\nF.\nAerosol Errors in Umkehr Ozone Profile\nMeasurements\nIII. Monitoring Erythermal Ultraviolet Radiation at the\nGround\n38\nIV. Ground-based Monitoring of Chlorofluorocarbons\n(CC13F and CC12F2) and Nitrous Oxide (N20)\n40","GEOPHYSICAL FLUID DYNAMICS LABORATORY\n45\nI. Three-Dimensional Modeling of Trace Constituent\nBehavior\n45\nA.\nAtmospheric N2O Experiments\nB.\nReactive Nitrogen in the Troposphere\nC.\nA Revised Hypothesis for the Origin of\nTropospheric Ozone\nD.\nExamination of the Classical Theory for\nTropospheric Ozone\nE.\nReview of Stratospheric Trace Constituent\nTransport\nF.\n\"Maximum Insight\" Tracer Experiments\nG.\nStratospheric Aircraft Pollution Experiment\nII. Modeling of the Troposphere-Stratosphere-Mesosphere\nSystem\n48\nA.\nLow Resolution (N10) Annual Cycle Experiment\nB.\n\"Low Diffusion\" Medium Resolution (N18) Experiment\nC.\nModel Analysis Technique Development\nD.\nSimpler Models for the Interaction Between Waves\nand Flows\nIII. Modeling of Radiative and Chemical Processes\n51\nA.\nComputation of Infrared Cooling Rates\nB.\nParameterization of Scale-Dependent Radiative\nDamping\nC.\nIncorporation of Ozone Chemistry in the Global\nCirculation Model (GCM)\nD.\nRadiative - Photochemical Interaction\nSPACE ENVIRONMENT LABORATORY\n56\nI. Monitoring Solar Ultraviolet Radiation from\nSatellite - and Ground-based Instruments\n56\nNATIONAL EARTH SATELLITE SERVICE\n58\nI. The TIROS Operational Satellite Vertical Sounder\n(TOVS)\n58\nII. Development and Operational Implementation of the\nSatellite Solar Backscatter Ultraviolet Ozone\nMonitoring System\n58\nIII. Evaluation of the Global TOVS Total Ozone Data\n59","NATIONAL WEATHER SERVICE CLIMATE ANALYSIS CENTER\n.....60\n60\nI. Operational Stratospheric Monitoring\nII. Examination of Available Ozone Data for Trend\n61\nDetection\n63\nENVIRONMENTAL DATA AND INFORMATION SERVICE.\n63\nI. Archiving TOVS Sounding Data","INTRODUCTION\nSection 126, on \"Ozone Protection,\" of P.L. 95-95, Clean Air\nAct Amendments of 1977, requires that \"The Administrator of the\nNational Oceanic and Atmospheric Administration shall establish a\ncontinuing program of research and monitoring of the stratosphere\nfor the purpose of early detection of changes in the stratosphere\nand climatic effects of such changes. Such Administrator shall\non or before January 1, 1978, and biennially thereafter, transmit\na report to the Administrator ( of EPA) and the Congress on the\nfindings of such research and monitoring.\" Significant\ncomponents of the mandated program have been in progress in NOAA\nfor several years.\nAs part of its assigned mission responsibilities in Upper\nAtmospheric and Space Research, Global Monitoring of Climate\nChange, Basic Weather Analysis, and Environmental Modeling, NOAA\nand its predecessors have conducted modest programs of research\nand monitoring of the stratosphere for several decades. These\nprograms were intensified when national concern developed about\nthe possible effects of chlorofluorocarbon releases and other\npollutants on stratospheric ozone.\nNOAA's stratospheric research and monitoring activities are\nconducted in six of its centers as follows: The Aeronomy\nLaboratory, the Air Resources Laboratories, the Geophysical and\nFluid Dynamics Laboratory, the Office of Research of the National\nEnvironmental Satellite Service, the Climate Analysis Center of\nthe National Weather Service, and the Satellite Data Service\nDivision of the Environmental Data and Information Service's\nNational Climatic Center.\nThe Aeronomy Laboratory conducts stratospheric composition\nmeasurements, laboratory reaction kinetics measurements, model\ncalculations, and atmospheric dynamics measurements.\nThe Air Resources Laboratories monitors stratospheric ozone\nand temperature variations, measures erythemal ultraviolet\nradiation at the ground, operates the U.S. portion of the World\nMeteorological Organization Global Ozone Research and Monitoring\nNetwork, and is developing an improved stratospheric water vapor\nmonitoring technique.\nThe Geophysical Fluid Dynamics Laboratory conducts\nmathematical modeling on the dynamical, radiative and chemical\nprocesses of the troposphere, stratosphere and mesosphere, with\nparticular attention to the climate effects of atmospheric and\noceanic changes in the global environment.\n- 1 -","The Office of Research of the National Environmental\nSatellite Service develops and evaluates NOAA programs for\noperational satellite measurements of stratospheric properties.\nThe Climate Analysis Center of the National Weather Service\nconducts analyses of stratospheric meteorological and ozone data\nfrom both ground-based and satellite measurement systems,\nutilizing data provided by all participating United States\nagencies.\nThe Satellite Data Service Division of the Environmental\nData and Information Service's National Climatic Center archives\nthe data from the operational satellites, and provides data to\nusers and researchers upon request.\nIndividual presentations of the stratospheric research and\nmonitoring activities of each of the above centers are\nincorporated in this report following the Summary of Findings,\n1980-1981.\n- 2 -","BACKGROUND\nThe National Oceanic and Atmospheric Administration and its\npredecessor organizations began systematic measurements of\natmospheric ozone in the late 1950's. Total ozone measurements\nwere included in the regular work of the four NOAA baseline\nstations, beginning in the early 1960's for Mauna Loa, Hawaii and\nSouth Pole, and in the mid-70's at Barrow, Alaska and Tutuila,\nAmerican Samoa.\nA network of stations for the specific purpose of monitoring\nozone was established in 1963 in Bismarck, ND, Caribou, ME, and\nNashville, TN, to which was added Boulder, CO in 1967. Three\nother stations were started which are no longer operated. In\naddition, NOAA began in the early 70's the coordination and\nprocessing of ozone measurements made by the National Aeronautics\nand Space Administration at Wallops Island, VA, the Army at White\nSands, NM, Florida State University at Tallahassee, FL, and a\ncooperative station operated by the Peruvian Government at\nHuancayo, Peru.\nThe World Meteorological Organization (WMO) established in\nthe mid-70's a Global Ozone Research and Monitoring Program in\nresponse to the perceived threat to the earth's ozone layer.\nOzone provides the ultraviolet shield which permitted animal and\nplant life to emerge from the oceans and live on land in open\ndaylight. The concern was voiced that the relationships among\nozone, ultraviolet radiation and life may be fragile and that any\nalteration of the stratospheric ozone abundance should be viewed\nwith concern. Ozone is an important controlling factor in the\ntemperature of the stratosphere, and changes in its concentration\nmay produce significant climatic changes. Monitoring of the\nvertical distribution of ozone in both the troposphere and\nstratosphere is essential for the early detection of changes\nwhich may affect the value of the total column of ozone.\nThe immediate impact of the WMO program was to encourage all\nmember nations to upgrade their ozone measuring stations, and to\ncarry out inter-calibrations essential to an international\nmonitoring network. International intercomparisons were held at\nAspendale, Australia in 1972, Belsk, Poland in 1974 and Boulder,\nUnited States in 1977. NOAA maintains the world standard Dobson\nozone spectrophotometer, No. 83, at Boulder, CO. A program to\nupgrade and calibrate Dobson spectrophotometers against the world\nstandard operated by the United States is being carried out by\nNOAA, funded through contributions from the WMO, participating\nnations, and NOAA.\nContinually created by photochemical reactions in the middle\nstratosphere, ozone is highly reactive gas. It is destroyed by\nreactions with many other substances, most importantly those of\nthe nitrogen, chlorine, and hydrogen families. The ozone\n- 3 -","abundance is vulnerable to human actions which increase the\namounts of these substances above the natural equilibrium level\nin the stratosphere, such as the release of halocarbons,\nparticularly the chlorofluorocarbons CC1 3 F and CC1 2 F 2' into the\natmosphere. To understand the causes of changes in ozone\nconcentrations, stratospheric measurements of relevant trace\nconstituents and processes must be undertaken. NOAA instituted a\nprogram of balloon sampling of the stratosphere in 1975 to\nmeasure a number of these constituents. This program has been\nexpanded to the Southern Hemisphere in recent years.\nNatural features in ozone include the poleward transport of\nozone, resulting in an increase of ozone concentration from\nequator to pole, seasonal variation of as much as 25 percent in\nthe temperate latitudes, possible shifts due to changes in solar\nactivity, and local changes due to the passage of weather systems\nin the lower atmosphere. For these reasons monitoring requires\nmeasurement capabilities plus analysis techniques operated over\na\nsufficiently long period of time to allow for an understanding,\nand removal statistically, of the natural variations to permit\nthe detection of a trend change which exceeds the natural\nvariability.\nOzone monitoring as an early warning system faces a number\nof significant limitations. For example, due to the time delay\nbetween halocarbon release and ozone destruction, the maximum\nozone decrease in the stratosphere from release of halocarbons in\nthe atmosphere would occur some 15 years later, even if we assume\na scenario in which the release of halocarbons is kept constant\nat present level. An effective early warning monitoring system\nmust be capable of detecting changes and verifying the causes\nthereof in time for corrective actions needed to prevent this\ndelayed maximum ozone decrease reaching greater than acceptable\nlevels. The WMO Dobson spectrophotometer network, within the\nnext decade, is not likely to be able to identify a reduction in\nglobal total ozone of less than 2 percent. The models predict\nthat such an ozone change will not occur before the year 2000,\nassuming halocarbon release at the present rate. However, model\ncalculations have shown that the predicted decrease in ozone\nconcentrations at 40 km is about five times as great as is the\ndecrease in total ozone. Monitoring ozone concentrations at this\naltitude should therefore provide a more sensitive early warning\nsystem in the context of an understanding of concurrent changes\nthrough the total ozone column.\nNOAA and NASA are now exploring the feasibility of\nestablishing an operational satellite vertical ozone profile\nmonitoring system. The ground-based Dobson ozone network plus\nrocket and balloon ozonesonde networks will continue to be needed\nfor verification and calibration of the satellite measurements.\nAdvantages of the satellite system include global coverage with a\nsingle instrument and real-time data acquisition.\n- 4 -","SUMMARY OF FINDING'S\n1980 - 1981\nI. OZONE MONITORING\nA.\nFindings from the Global Ozone Observation Network\nAnalysis of the World Meteorological Organization's\nGlobal Ozone Monitoring Network data through the year 1980 was\ncompleted. Figure 1 shows the variation in year-average total\nozone from 1958 through 1980 for each hemisphere and the world\ntotal, expressed as a percentage deviation from the me an for the\nperiod 1958-1977. The vertical bars are confidence limits such\nthat there is about a 95 percent chance that the true value of\nthe annual mean lies within the extent of these bars.\nThe world total-ozone concentration, observed to be a\nsignificant 2.2 percent above the average in 1979, decreased to a\nnon-significant 0.3 percent above average in 1980. All climatic\nzones, as well as all regions in the north-temperate climatic\nzone, registered a decrease in total ozone between 1979 and\n1980. However, there is little evidence from the ground-based\nGlobal Ozone Monitoring Network of a significant trend in total\nozone during the 1970's for either hemisphere or for the world.\nPhotochemical modeling predicts that the largest percentage\nof ozone depletion from chlorofluorocarbon releases would occur\nnear the 40 km level, and hence anthropogenic effects might first\nbe noted near this level. Crude estimates of the ozone\nconcentration at these heights can be obtained by ground based\nozone profile measurements (Umkehr observations) carried out at\na\nlimited number of Dobson spectrophometer stations. Figure 2\nshows year-average values by this method for north temperate\nlatitudes. (Note change in ordinate scale from Figure 1.) The\nUmkehr data are presented for stratospheric height-layers 32-48\nkm, 24-32 km, and 16-24 km. For comparison, ozonesonde data are\npresented for height layers 24-32 km and 16-24 km based on\nobservations in North America, Europe and until recently,\nJapan. The volcanic eruptions of Agung and Fuego are shown at\nthe top of Figure 2. The indicated ozone decrease following\nthese eruptions is mostly an artifact in the measurements\nresulting from the presence of volcanic aerosols in the\nstratosphere.\nIn the critical 32-48 km layer the Umkehr year-average\nvalue, which in 1979 was a significant 4.3 percent above the\naverage, in 1980 declined to a non-significant 2.9 percent above\naverage. However, there is little evidence from the Umkehr\nobservations of a significant trend in the 32-48 km ozone amount\nin north temperature latitudes during the 1970's.\n- 5 -","Total Ozone\n6\n4\n&\nFOR\n2\nof\nNORTHERN\n0\nHEMISPHERE\n-2\n-4\n4\n2\nSOUTHERN\n0\n11911\nHEMISPHERE\n-2\n-4\n4\nHO\n2\nWORLD\n0\n-2\n-4\n-6\n1960\n1965\n1970\n1975\n1980\nFigure 1. . Variation in year-average total ozone for hemispheres and world,\nexpressed as a percentage deviation from the mean.\nVertical bars - there is about a 95 percent chance that the true\nvalue of the annual mean lies within the vertical bars.\n- 6 -","North Temperate Layer-Mean Ozone\n12\n8\n4\n0\n32 - 48 km\nUMKEHR\n-4\n-8\nFUEGO\n8\nAGUNG\n4\n0\n24 - 32 km\nUMKEHR\n-4\n4\n0\n24 - 32 km\nOZONESONDE\n-4\n-8\n8\n4\n0\n16 - 24 km\nUMKEHR\n-4\n-8\n4\n0\n16 - 24 km\nOZONESONDE\n-4\n-8\n1960\n1965\n1970\n1975\n1980\nFigure 2. Variation in year-average ozone in stratospheric layers of\nnorth temperate latitudes, from Umkehr and ozonesonde measure-\nments.\n- 7 -","B.\nModel Predicted Ozone Trends\nThe results of recent model predictions of the total\ncolumn ozone trend for the decade 1970 to 1980, considering only\ncontinuing worldwide emissions of chlorofluorocarbons, is\n-0.7%. Since the increases during this decade of carbon dioxide\nand nitrogen oxides tend to increase ozone abundances, the\ncombined effect of increasing chlorofluorocarbons, carbon dioxide\nand nitrogen oxides on the total column ozone trend for the\ndecade is -0.1%. Uncertainties involved with these predictions\nare about a factor of 3. The model predicted ozone trend for\nthis decade for the Umkehr layer at 32-48 km is -3.5% for the\nchlorofluorocarbons only and -2.5% for the combined scenario.\nUncertainties in these predictions are about a factor of two.\nIt is important to recognize that to detect the model\ncalculated ozone trends through monitoring we need to understand\nthe long-term natural variabilities of ozone and the precisions\nof' ozone observations. Long term natural variations of ozone on\nthe same order as the current model predicted chlorofluorocarbon\neffect may result from changes in solar flux, cosmic rays,\nstratospheric water vapor, methane, and stratospheric\ncirculations. There is little information on the long term\nchanges of these parameters. Therefore, even if a definitive\ntrend of ozone is observed, one could not rule out at this time\nthe possibility that the trend is due to natural variabilities\nrather than a result of anthropogenic effects. With regard to\nthe precisions of ozone observations, the uncertainties in the\nDobson total column ozone observations during the decade 1970-79\nare about 1 to 2% per decade. The uncertainties in Umkehr ozone\nmeasurements at 38-42 km altitude are about 10% per decade.\nThese uncertainties are greater than the model calculated ozone\ntrends for the decade.\nII. STRATOSPHERIC WATER VAPOR MEASUREMENTS\nA balloon-borne, fast-response, self-calibrating instrument\nfor the in-situ measurement of stratospheric water vapor was\ndesigned, developed and flown. There have been a total of ten\nsuccessful flights from Wyoming, Texas and Brazil, the results of\nwhich have contributed significantly toward the understanding of\ntropospheric-stratospheric exchange processes.\nAlmost all of the flights have found that the stratospheric\nwater vapor concentrations have a minimum just above the\ntropopause and increase with increasing altitude. Moreover, a\ncomparison of the Wyoming flights with the Brazil flight suggests\nthat stratospheric water vapor increases from the tropics to mid-\nlatitudes. Both of these observed vertical and meridional\nincreases are consistent with a stratospheric source of water\nvapor, such as the oxidation of methane.\n- 8 -","III. STRATOSPHERIC TEMPERATURE MONITORING\nOzone plays an important role in the radiation balance of\nthe earth-atmosphere system, thus influencing global climate.\nHeat generated in the stratosphere by ozone absorption of solar\nradiation provides the principal driving force for stratospheric\nwind systems, and thus controls the climate of the stratosphere.\nMonitoring of stratospheric temperature is important also\nbecause current and impending stratospheric cooling as a result\nof long-wave radiation from increasing carbon dioxide will affect\nthe rate at which temperature-dependent chemical changes will\noccur which are relevant to the ozone balance. Figure 3 (see Air\nResources Laboratory, Section I) shows the variation in year-\naverage temperature from rocketsonde data from 1965 through 1979\nin the Northern Hemisphere. The rocketsonde data show a large\ntemperature decrease between 1970 and 1976, with only a hint of a\nwarming thereafter. (This cooling is much too large to be\nassociated, in toto, with a carbon dioxide effect.) However, the\nradiosonde data for the 16-24 km layer (through 1980) show little\ntemperature variation since the warming following the eruption of\nthe Agung volcano. The differences between the rocketsonde and\nradiosonde derived temperature variations may result from the\ndifferent altitudes, and do not necessarily point up an\ninconsistency.\nIV. THE ORIGIN OF TROPOSPHERIC OZONE\nCollaborative studies between Aeronomy Laboratory and\nGeophysical Fluid Dynamics Laboratory scientists coupled with\ndirect measurements of NO and NO 2 profiles have indicated that\nstratospheric ozone is not the sole source of most tropospheric\nozone. By using the measured distribution by altitude of NO and\nNO. in combined photochemical and general circulation model\ncaIculations, a study demonstrated that recent observational\nevidence was consistent with the photochemical production of\nozone in the upper troposphere, catalyzed by NO and NO, the\nsource of which is predominantly the downward transport of\nreactive nitrogen from the lower stratosphere to the upper\ntroposphere.\nThis finding suggests that significant ozone production due\nto subsonic aircraft emissions of reactive nitrogen could\noccur. This may explain the ozonesonde measured Northern\nHemisphere tropospheric ozone increase of about 10% in the decade\nfrom 1971-1980. This increase represents about a 1% increase in\ntotal column ozone, which would tend to offset somewhat any\nstratospheric decrease due to halocarbons which may have\noccurred. This must be investigated in more detail in order to\nunderstand the strength of these two opposing effects in the\ntotal column ozone determinations.\n- 9 -","AERONOMY LABORATORY\nBoulder, Co.\nThere are many individual aspects that must be understood\nand combined in order to reach a comprehensive understanding of\nstratospheric behavior. The concentrations of a number of\nnatural and anthropogenic chemical species must be known,\nincluding their temporal and spatial variabilities. This leads\nto a requirement for determining stratospheric chemical\ncomposition, in some cases for species occuring in extremely low\nconcentration. The photochemistry of the atmosphere must be\nknown in order to assess the influence of changes in atmospheric\ncomposition on the ozone layer. This requires sophisticated\nlaboratory reaction rate measurements. The motions and transport\nof atmospheric species influence atmospheric processes.\nMeasurements of atmospheric diffusion, turbulence, temperature,\nand wind fields are required.\nThe data on atmospheric composition, photochemical reaction\nkinetics and transport must be incorporated into theoretical\nmodels, which serve as the tools for predicting future effects.\nThe whole stratospheric research program in a sense is an effort\nto refine and sharpen these tools.\nThe stratospheric ozone layer affects man and his activities\nin both direct and indirect ways. Ozone absorbs nearly all of\nthe harmful ultraviolet radiation from the Sun that would\notherwise irradiate the surface of the Earth and its living\norganisms, and it also plays a role in the radiation balance of\nthe earth-atmosphere system, thereby helping to determine the\nparameters of global climate. In addition, the heat generated\nlocally in the stratosphere by absorption of solar radiation\nprovides the principal driving force for stratospheric wind\nsystems, and thus controls the climate of the stratosphere\nitself. The potential consequences of change in stratospheric\nozone are thus a matter of serious practical concern, and the\nstratospheric program of the Aeronomy Laboratory is directed\ntoward elucidating the various factors that determine the ozone\nconcentration. During 1980 and 1981 the Aeronomy Laboratory\ncarried out active programs in all of these areas of\nstratospheric research, the central theme being provided by the\nproblem of stratospheric ozone.\nI. MODEL CALCULATIONS\nThe Aeronomy Laboratory has continued to play a leading role\nin the development and use of atmospheric models to predict the\nbehavior of stratospheric ozone. The models themselves have\nprogressed from the relatively simple one-dimensional versions\nwith only vertical transport to more complex two-dimensional\n- 10 -","models that included latitudinal transport. Incorporation of\nphotochemistry in existing three-dimensional general circulation\nmodels of the Geophysical Fluid Dynamics Laboratory (GFDL) of\nNOAA is progressing, and will ultimately lead to a fuller\nundestanding of the influence of ozone changes on global\nclimate. See Geophysical Fluid Dynamics Laboratory, Section III\nC) .\nA.\nSteady-State Depletion of Total Ozone Abundance Due to\nChlorofluoromethane Emissions\nBecause of the changes during 1980-81 in the reaction\nrate coefficients of HNO and HNO NOAA's Aeronomy Laboratory 1- -\nD model predicted reduction at steady state of ozone column\nabundance due to a constant rate of CFM emission at the 1975 rate\nis now about 7% 1 For comparison, the previous estimate was\n18% 2 However, the model predicted effects to the ozone column\nabundance due to stratospheric aircraft and nitrogen fertilizers\nhave increased because of the changes in these reaction rate\ncoefficients. 1\nThe Origin of Tropospheric Ozone\nB.\nCollaborative model studies between Aeronomy Laboratory\nand Geophysical Fluid Dynamics Laboratory Scientists coupled with\ndirect measurements of NO and NO2 profiles have indicated that\nstratospheric ozone is not the sole source of most tropospheric\nozone. The origin of tropospheric ozone has been a controversial\nand unresolved question between theories of downward transport of\nstratospheric ozone and in situ photochemically controlled\nproduction by sources and sinks near the surface in the\ntroposphere. By using the measured distribution by altitude of\nNO and NO in combined photochemical and general-circulation\nmodel calculations, a study demonstrated that recent evidence was\nconsistent with the photochemical production of ozone in the\nupper troposphere catalyzed by NO and NO2 the source of which is\npredominantly the downward transport of reactive nitrogen from\nthe lower stratosphere to the upper troposphere. Calculations\nindicate that photochemical ozone production initiated by\nreactive nitrogen in this process can produce as much or more\nozone than is provided by the direct ozone flux. The added sink\nof ozone required is found in the lower troposphere by way of a\nwater vapor related ozone destruction path.\nThis finding suggests that significant ozone production due\nto subsonic aircraft emissions of reactive nitrogen could occur,\nwhich must be investigated in more detail. This may explain the\nozonesonde measured Northern Hemisphere tropospheric ozone\nincrease of about 10% in the last decade. This increase\nrepresents about 1% increase in total column ozone, which would\ntend to offset somewhat any stratospheric decrease which may have\n- 11 -","occurred. Therefore, it will be important to investigate the\naltitude distribution of ozone both in the stratosphere and the\ntroposphere in order to understand the relative strengths of\nthese two opposing effects in the total column ozone\ndeterminations from ground-based and satellite measurement\nsystems and in appropriate form in model calculations.\nEffects of Particle Precipitation Events\nC.\nTwo-dimensional studies in collaboration with\nscientists of the University of Colorado and the National Center\nfor Atmospheric Research have evaluated the effects of particle\nprecipitation events on the mesosphere and stratosphere. 5,6\nThe\neffect on odd nitrogen is important in the understanding of the\nnatural variation of stratospheric ozone.\nCoupled Radiative and Chemical Models\nD.\nThe one-dimensional steady-state and time-dependent\nmodels are being used in conjunction with the one-dimensional\nradiative model of the Geophysical Fluid Dynamics Laboratory of\nERL. The coupled models predict that chemical damping of\ngravity waves is not nearly as important as had previously been\nthought. This has led to a new approach to the problem, and the\nresults now predict a larger amount of damping, consistent with\nobservation, but basically from radiative effects rather than\nchemical.\nComparison of Theoretical and Measured Values\nE.\nThe one-dimensional combined steady-state and diurnal\nmodel has been used to compare theoretical values for the\nconcentrations of NO, NO2, HNO3, O3, and H2O with those measured\nin a balloon flight of the University of Denver. Agreement is\nvery good for NO, NO2 and HNO even though in the lower\nstratosphere the measured water-vapor concentration is much\nhigher and the measured ozone concentration is lower than a one-\ndimensional model would predict. This is probably a dynamical\nproblem arising from transport of H2O and O3, which are both\nlong-lived in the lower stratosphere.\n- 12 -","REFERENCES\n1.\nWMO Global Ozone Research and Monitoring Project, December\n1981, The stratosphere 1981: Theory and measurements,\nEditors: R. D. Hudson, E. I. Reed, and R. D. Bojkov.\n2. NASA Reference Publication 1049, The stratosphere: Present\nand future, Editors: R. D. Hudson and E. I. Reed,\nScientific and Technical Information Branch, NASA,\n1979.\n3. Liu, S. C. D. Kley, M. McFarland, J. D. Mahlman, and H.\nLevy II, On the orgin of tropospheric ozone, J.\nGeophys.\nRes. 85, 7546-7552, 1980.\n4. Fishman, J., V. Ramanathan, P. J. Crutzen, and S. C. Liu,\nTropospheric ozone and climate, Nature, 282, 818-820,\n1979.\nRusch, D. W., J.-C. Gerard, S. Solomon, P. J. Crutzen, and\n5.\nG .C. Reid, The effect of particle precipitation events\non the neutral and ion chemistry of the middle\natmosphere. I. Odd nitrogen, to appear in Planet.\nSpace Sci., 1981.\n6.\nSolomon, S. D. W. Rusch, J.-C. Gerard, G. C. Reid, and P.\nJ. Crutzen, The effect of particle precipitation events\non the neutral and ion chemistry of the middle\natmosphere. II. Odd hydrogen, to appear in Planet.\nSpace Sci., 1981.\n7.\nFels, S. B. and M. D. Schwarzkopf, An efficient algorithm\nfor calculating CO2 15um band cooling rates, J.\nGeophys. Res. 86, 1205-1232, 1981.\n8.\nBlatherwick, R. D., A. Goldman, D. G. Murcray, F. J.\nMurcray, G. R. Cook, and J. W. Van Allen, Simultaneous\nmixing ratio profiles of stratospheric NO and NO2 as\nderived from balloon-borne infrared solar spectra,\nGeophys. Res. Lett. 7, 471-473, 1980.\n- 13 -","II. STRATOSPHERIC WATER VAPOR MEASUREMENTS\nStratospheric water vapor concentrations provide insight\ninto two atmospheric processes. First, water vapor serves as an\nexcellent tracer of tropospheric-stratospheric exchange and\ntransport processes, because the concentrations reflect the\ntemperature of the tropopause through which the water vapor\nentered the stratosphere. In addition to this tracer role, H20\nconcentrations reflect aspects of stratospheric transport and\nchemical processes.\nWith the goal of using stratospheric water vapor as a window\ninto these processes, a balloon-borne, fast-response, self-\ncalibrating instrument for the in-situ measurement of\nstratospheric water vapor was designed, developed, and flown by\nNOAA scientists. Since 1978, there have been a total of ten\nsuccessful flights from Wyoming, Texas, and Brazil, the results\nof which have already contributed significantly toward the\nunderstanding of tropospheric-stratospheric exchange processes.\nThe stratospheric H20 concentrations over Wyoming have been\nfound to be too low to have entered the stratosphere by crossing\nthe tropopause at this latitude. 5 The concentrations\nindicate\nthat this water vapor crossed the tropical tropopause into the\nstratosphere, and was subsequently carried poleward.\nAlmost all of the flights have found that the stratospheric\nH2O concentrations have a minimum just above the tropopause and\nincrease with increasing altitude. Moreover, a comparison of the\nWyoming flights with the Brazil flight suggests that\nstratospheric H2O increases from the tropics to mid-latitudes.\nBoth of these observed vertical and meridional increases are\nconsistent with a stratospheric source of H2O, such as the\noxidation of methane.\nThe stratospheric water vapor detector has been redesigned\nto operate in the daytime. The first application of this new\ndesign has been built into an instrument that is carried aboard\nNASA's U2 aircraft, which flies up to 21 km. This research\nplatform offers serveral hours flight time at many global\nlocations. The first application was in Panama in the late\nsummer of 1980. This mission explored tropical tropospheric-\nstratospheric exchange processes. The stratospheric water vapor\ninstrument clearly identified significant upwellings into the\nstratosphere. Their structure and their relation to the air\nmotions in this region are being examined. Several long-distance\nflights out of Moffett Field, California, have explored the\nlongitudinal and latitudinal variations of stratospheric water\nvapor.\n- 14 -","An international intercomparison of stratospheric and\ntropospheric water vapor sounding instrumentation was conducted\nunder the leadership of the Federal Aviation Agency at Palestine,\nTexas in May, 1981 with generally good agreement among a variety\nof in-situ measuring techniques.\n- 15 -","REFERENCES\nSchmeltekopf, A. L., P. D. Goldan, W. R. Henderson, W. J.\n1.\nHarrop, T. L. Thompson, F. C. Fehsenfeld, H. I. Schiff,\nP. J. Crutzen, I. S. A. Isaksen, and E. E. Ferguson,\nMeasurements of stratospheric CFC13, CF2C12, and N20,\nGeophys. Res. Lett. , 2, 393-396, 1975.\n2. Goldan, P. D., W. C. Kuster, D. L. Albritton, and A. L.\nSchmeltekopf, Stratospheric CFC1, 3' CF2C12, and N20\nheight profile measurements at several latitudes,\nJ. Geophys. Res., , 85, 413-423, 1980.\nSchmeltekopf, A. L., D. L. Albritton, P. J. Crutzen, P. D.\n3.\nGoldan, W. J. Harrop, W R. Henderson, J. R. McAfee, M.\nMcFarland, H. I. Schiff, T. L. Thompson, D. J. Hoffman,\nand N. T. Kjome, Stratospheric nitrous oxide altitude\nprofiles at various latitudes, J. Atmos. Sci . 34,\n729-736, 1977.\nKley, D. , and E. J. Stone, Measurement of water vapor in the\n4.\nA)\nstratosphere by photodissociation with Ly & (1216\nlight, Rev. Sci. Instrum. , 49, 691-697, 1978.\nKley, D., E. J. Stone, W. R. Henderson, J. W. Drummond, W.\n5.\nJ. Harrop, A. L. Schmeltekopf, T. L. Thompson, and R.\nH. Winkler, In situ measurements of the mixing ratio of\nwater vapor in the stratosphere, J. Atmos. Sci., 36,\n2513-2524, 1979.\n- 16 -","III. IN-SITU STRATOSPHERIC COMPOSITION MEASUREMENTS\nThe principal natural loss mechanism for stratospheric ozone\nis through catalytic reaction with nitric oxide (NO), which is in\nturn produced mainly by reaction of excited oxygen atoms with\nnitrous oxide (N20). The principal anthropogenic loss mechanism\nfor ozone is thought to be through catalytic reaction with\nchlorine atoms released by sunlight from the chlorofluorocarbons\nF-11 (CFCL3) and F-12 (CF2CL2), which are used as refrigerants\nand as spray can propellants. A balloon sampling program was\ninitiated in the Aeronomy Laboratory in 1975, aimed at measuring\nthe stratospheric concentrations of both the chlorofluoromethanes\nand N20. The challenge was great, since the program called for\nmeasurements of concentrations in the range of parts per trillion\n(10-12). The initial results had a major impact on the field.\nThe results of 24 flights over the last three years have been\nsummarized recently. 2 This extensive data set has implications\nfor many areas of atmos pheric chemistry.\nThe chlorofluorocarbon data set clearly shows steady\na.\ntemporal increases in the ambient tropospheric levels of these\nchemicals, increases that closely parallel the estimated release\nrates. These data are being used in models that are aimed at\nbetter understanding of the ozone-depletion problem.\nFurthermore, the clear differences observed between the two\nhemispheres provide information about interhemispheric transport,\nsince the release of these species is primarily in the northern\nhemisphere.\nb. The N20 data set demonstrates that there have been some\nincreases in the tropospheric levels of this constituent, these\nhave not been large.\nRecent balloon flights have employed a larger set of\nC.\nsampling devices. With this finer sampling grid, the monotonic\nlapse rates of CFCL3, CF2C12 and N2O concentrations expected from\ndiffusion and photochemistry alone have been observed\noccasionally to be perturbed quite markedly. These observations\nindicate that significant air movements were taking place,\ncausing air masses containing higher mixing ratios of these\nspecies to intrude into or over regions where the mixing ratios\nwere lower.\nIV. LABORATORY KINETICS MEASUREMENTS\nThe photochemistry of the stratosphere is highly complex,\nand involves a very large number of chemical reactions. In order\nto understand and predict the composition of the stratosphere, it\nis essential that the rates of the important reactions be known,\nand the only reliable method of deducing reaction rates at\n- 17 -","present is to measure them in the laboratory. The Aeronomy\nLaboratory has had a leading position in laboratory reaction-rate\nmeasurements for many years, and within the past few years the\nprogram has been directed toward measurement of the reactions of\nimportance to stratospheric photochemistry.\nA major part of the laboratory kinetics program involves\ndeveloping methods of detecting important atmospheric\nmolecules. A tunable diode laser, originally developed for\nstudying high resolution infrared spectroscopy, was used to\nanalyze whole air samples for their N2O content. 1 Nitrous oxide,\nN2O, is very important in the stratosphere where it is the main\nsource of the nitrogen oxides which are ozone destruction\ncatalysts. The spectroscopic measurement that was made of the\nN2O concentration in air settled a major discrepancy amoung\nseveral laboratories with extensive N2O measurement programs.\nThe conclusion of this study was that a significant error existed\nin the calibration standards used by these laboratories.\nKinetic measurements have been made on the atmospheric\nreactions of C10, chlorine monoxide, with nitrogen oxides NO and\nNO2 using a laser magnetic resonance system. 2 These reactions\nact to reduce the ozone destruction by the chlorine species. The\ntemperature and pressure behavior of the reactions were studied\nas well.\nThe first measurement of a new reaction path in the reaction\nof HO2, the hydroperoxyl radical, with chlorine atoms was made. 3\nThe reaction of HO2 with C1 is a major removal process for\nstratospheric chlorine because inert HC1 is formed. This study\ndemonstrated that different products, namely, C10 and OH,\nhydroxyl radicals, are also produced. This path has a completely\ndifferent effect on ozone because these products are not inert.\nResearch has continued on the study of atmospheric ion-\nmolecule reactions. Although no reaction of ions has been found\nto be significant in stratospheric ozone chemistry, ion chemistry\nhas been shown to be a valuable probe of the composition of the\nstratosphere. For example, measurements of the ionic composition\nof the stratosphere when combined with laboratory kinetic data\nhave provided the first data on the amount of sulfuric acid in\nthe stratosphere. Other laboratory studies of ion reactions have\nallowed predictions of the role of meteoric metals in the\nstratosphere to be made 5-8 This subject remains controversial as\nsome scientists have suggested that these metals may act to\nneutralize the catalytic chlorine species.\n- 18 -","REFERENCES\n1. Connell, P. S. , R. A. Perry, and C. J. Howard, Tunable diode\nlaser measurement of nitrous oxide in air, Geophys.\nRes. Lett., 7, 1093-1096, 1980.\n2.\nLee, Y.-P., , R. M. Stimpfle, R. A. Perry, J. A. Mucha, K. M.\nEvenson, D. A. Jennings, and C. J. Howard, Laser\nmagnetic resonance spectroscopy of C10 with NO and NO2,\nsubmitted to Int. J. Chem. Kinet. (1981).\n3. Lee, Y.-P., , and C. J. Howard, Temperature dependence of the\nrate constant and the branching ratio for the reaction\nC1 + HO2, submitted to J. Chem. Phys. (1981).\n4. Viggiano, A. A., , R. A. Perry, D. L. Albritton, E. E.\nFerguson, and F. C. Fehsenfeld, The role of H2SO4 in\nstratospheric negative-ion chemistry, J. Geophys. Res.,\n,\n85, 4551-4555, 1980.\n5.\nPerry, R. A., , B. R. Rowe, A. A. Viggiano, D. L. Albritton,\nE. E. Ferguson, and F. C. Fehsenfeld, Laboratory\nmeasurements of stratospheric sodium ion reactions,\nGeophys. Res. Lett., 7, 693-696, 1980.\n6.\nFerguson, E. E., B. R. Rowe, D. W. Fahey, and F.C.\nFehsenfeld, Magnesium ion chemistry in the\nstratosphere, Planet. Space Sci., 29, 479-481, 1981.\n7.\nFerguson, E. E., D. W. Fahey, F. C. Fehsenfeld, and D. L.\nAlbritton, Silicon ion chemistry in the ionosphere,\nPlanet. Space Sci., 29, 307-312, 1981.\n8.\nFahey, D. W. , F. C. Fehsenfeld, and E. E. Ferguson,\nReactions of Si+ with H2O and O2 and Si0+ with H2 and\nD2, J. Chem. Phys., 75, 669-674, 1981.\n- 19 -","V. REMOTE SPECTROSCOPIC MEASUREMENTS\nA major development in our knowledge of the distribution of\nnitrogen oxides in the stratosphere took place in the Aeronomy\nLaboratory through the use of ground-based spectroscopic\nmeasurements. The technique is basically very simple, and\ninvolves measurement of the intensity of sunlight or moonlight in\na region of the spectrum that is subject to absorption by\nnitrogen dioxide (NO) Comparison with intensities in\nneighboring regions that are free of absorption then determines\nthe column density of NO2 in the atmosphere along the line of\nsight.\nThis technique has been applied to determine the diurnal,\nseasonal, and latitudinal variation of stratospheric NO by means\nof a series of measurements carried out at a fixed location near\nBoulder, and also in a number of mobile platforms, including jet\naircraft (in cooperation with the Air Force Geophysics\nLaboratory) and a ship (in cooperation with the National Science\nFoundation). The NO2 concentration has been found to vary\nmarkedly with meteorological conditions, and to show a strong\ncorrelation with the large-scale stratospheric circulation\npattern. 1,2 Substantial changes are associated with stratospheric\nwarming events. 3 Automated instruments were installed at a\nnumber of stations in collaboration with NOAA'S GMCC program, and\nmeasurements made at Barrow, Alaska have confirmed earlier\nconclusions from aircraft observations concerning the high-\nlatitude behavior of stratospheric NO In winter, NO 2\nconcentrations within the polar vortex become very low, and the\ntransition between these low values and the more normal\nmidlatitude values occurs very abruptly as the observation point\nmoves to lower latitudes. Measurements made onboard a ship\nsailing northward up the South American coast have shown clearly\nthat NO2 behaves in the same way in both Northern and Southern\nHemispheres during the local winter.\nRecently a similar technique has been applied to measure\nnitrogen trioxide (NO3), which is another important member of the\nfamily of nitrogen oxides. Concentrations of NO are much\nsmaller than those of NO2, SO that the measurement is\nconsiderably more difficult, and the results have shown some\nunexpected features. For example, NO reaches its maximum\nstratospheric concentration in the spring, contrary to\ntheoretical expectations. Tropospheric NO 3 concentrations are\nmuch lower than expected. There are obviously unexplained\nanomalies in the behavior of NO that are likely to have\nimportant implications for our understanding of the chemistry of\nnitrogen oxides in the atmosphere.\n- 20 -","A long series of measurements of the hydroxyl radical, OH,\nhas been obtained at a location near Boulder by the use of\nspectroscopic techniques. 7 The OH radical is a species of\ncritical importance to stratospheric chemistry, but relatively\nfew measurements of its concentrations have been made. The\nobservations carried out in Boulder provide the first indication\nof the temporal variability of stratospheric OH, both with season\nand solar cycle.\nAeronomy Laboratory scientists have been involved for\nseveral years in the planning phases of the Solar Mesosphere\nExplorer satellite launched October 6, 1981. The stratospheric\nNO2 measurement spectrometer on the satellite is an adaptation of\nan experimental technique pioneered in the Aeronomy Laboratory\nand previously operated from ship and aircraft platforms and from\na number of stationary surface sites. Three Aeronomy Laboratory\nscientists are members of the satellite team and will be involved\nin analysis of data now returning from the satellite. In\naddition to NO2, SME will measure ozone by three different\ntechniques, water vapor, temperature and solar flux. This\ncoordinated data set should lead to improved understanding of the\nproduction and loss processes of stratospheric ozone. The NASA\nfunded satellite is operated by the Laboratory for Atmospheric\nand Space Physics of the University of Colorado with\ncollaborative support from NOAA and NCAR.\n- 21 -","REFERENCES\n1.\nNoxon, J. F . , E. C. Whipple, Jr., and R. S. Hyde,\nStratospheric NO2. 1. Observational Method and\nBehavior at Mid-Latitude, J. Geophys. Res. 84, 5047-\n5065, 1979.\n2. Noxon, J. F. Stratospheric NO2 2. Global Behavior,\nJ. Geophys. Res. , 84., 5067-5076, 1979.\n3. Noxon, J. F. , E. Marovich, and R. B. Norton, Effect of\na Major Warming Upon Stratospheric NO2, J. Geophys.\nRes., 84, 7883-7888, 1979.\n4.\nNoxon, J. F. , Stratospheric NO2 in the Antarctic Winter,\nGeophys. Res. Letters, 5, 1021-1022, 1978.\n5.\nNoxon, J. F. R. B. Norton, and W. R. Henderson,\nObservation of Atmospheric NO3, Geophys. Res. Letters, 5,\n675-678, 1978.\n6.\nNoxon, J. F. , R. B. Norton, and E. Marovich, NO3 in the\nTroposphere, Geophys. Res. Letters, 7, 125-128, 1980.\n7. Burnett, C. R. , and E. B. Burnett, Spectroscopic\nMeasurements of the Vertical Abundance of Hydroxyl (OH)\nin the Earth's Atmosphere, J. Geophys. Res., , 86, 5185-\n5202, 1981.\n- 22 -","VI. ATMOSPHERIC DYNAMICS MEASUREMENTS\nThe Aeronomy Laboratory's expertise in the field of radar\nbackscatter measurements of ionospheric motions has been applied\nto the problem of measuring the neutral-air motions associated\nwith the dynamics of the stratosphere. The laboratory has\ndeveloped the technique of using VHF Doppler radars to measure\nmotions of the clear air over a wide range of altitudes and\nscales of motion. 1 Radars have been constructed and are being\noperated at Sunset 2 and Platteville, Colorado, and at Poker Flat,\nAlaska 3 The latter radar, constructed with the support of the\nNational Science Foundation, is the largest radar in the world\ndedicated to study of the clear air. Using these facilities, the\nlaboratory is making important contributions to the study of\natmospheric dynamics at all scales, including\nturbulence, 6, 7,8, gravity (buoyancy) waves, 9,10,11\ntides, 12\n,\nplanetary waves, etc. Understanding of motions on these scales\nwill greatly improve our understanding of the ways in which minor\natmospheric constituents are transported into and out of the\nozone layer.\n- 23 -","REFERENCES\nBalsley, B. B. , and K. S. Gage, The MST radar technique:\n1.\nPotential for middle atmospheric studies, Pure and\nAppl. Geophys., 118, 452-492, 1980.\nGreen, J. L., J. M. Warnock, W. L. Clark, F. J. Eggert, and\n2.\nK. J. Ruth, Modifications to the Sunset radar to\nprovide antenna beam steering, Preprint Vol., 20th\nConf. on Radar Meteorology, Nov. 30- Dec. 3, 1981,\nBoston, AMS.\nBalsley, B. B., W. L. Ecklund, D. A. Carter, and P. E.\n3.\nJohnston,, The MST radar at Poker Flat, Alaska, Radio\nSci., 15, 213-223, 1980.\nGage, K. S., and B. B. Balsley, On the scattering and\n4.\nreflection mechanisms contributing to clear air radar\nechoes from the troposphere, stratosphere, and\nmesosphere, Radio Sci., 15, 243-257, 1980.\n5. Ecklund, W. L., D. A. Carter, and B. B. Balsley, Gradient-\ndrift irregularities in mid-latitude sporadic E,\nJ. Geophys. Res., 86, 858-862, 1981.\nNastrom, G. D., K. S. Gage, and B. B. Balsley, The\n6.\nvariability of Cn at Poker Flat, Alaska, from MST\nDoppler radar observations, submitted to Optical\nEngineering.\nNastrom, G. D., B B. Balsley, and K. S. Gage, Changes with\n7.\nseason of Cn 2 at Poker Flat, Alaska, from MST Doppler\nradar observations, Preprint Vol., 20th Conf. on Radar\nMeteorology, Nov. 30-Dec. 3, 1981, Boston, AMS.\nVanZandt, T. E., K. S. Gage, and J. M. Warnock, An 2 improved\n8.\nmodel for the calculation of profiles of Cn and in\nthe free atmosphere from background profiles of wind,\ntemperature and humidity, Preprint Vol., 20th Conf. on\nRadar Meteorology, Nov. 30-Dec. 3, 1981, Boston, AMS.\n9. Ecklund, W. L., K. S. Gage, and A. C. Riddle, Gravity wave\nactivity in vertical winds observed by the Poker Flat\nMST radar, Geophys. Res. Lett., 8, 285-288, 1981.\n10. Gage, K. S., D. A. Carter, and W. L. Ecklund, The effect of\ngravity waves on specular echoes observed by the Poker\nFlat MST radar, Geophys. Res. Lett., 8, 599-602, 1981.\n- 24 -","11. Balsley, B. B., , J. L. Green, W. L. Ecklund, W. L. Clark, R.\nG. Strauch, and A. C. Riddle, Joint observations of\ngravity wave activity in vertical winds in the\ntroposphere and lower stratosphere over a 63 km\nbaseline obtained with clear-air VHF radars at\nPlatteville and Sunset, Colorado, Preprint Vol., 20th\nConf. on Radar Meteorology, Nov. 30-Dec. 3, 1981,\nBoston, AMS.\n12. Ecklund, W. L., , B. B. Balsley, and D. A. Carter, The Poker\nFlat MST radar: Premliminary results between 3-20 km,\nPreprint Vol., AMS 19th Conf. on Radar Meteorology,\nApril 15-18, 1980, Miami Beach, FL, pp 557-562.\n- 25 -","AIR RESOURCES LABORATORIES\nSilver Spring, MD and Boulder, CO\nI.\nSTRATOSPHERIC TEMPERATURE MONITORING\nStratospheric cooling will affect the rate at which\ntemperature-dependent chemical changes will occur which are\nrelevant to the ozone balance. Monitoring of stratospheric\ntemperature is important because of the current or impending\ncooling of the stratosphere associated with an increase in carbon\ndioxide. Indeed, because the stratospheric cooling should be\nconsiderably greater than the tropospheric warming, it is the\nstratosphere that might provide the earliest warning of a CO 2\neffect.\nIn the Northern Hemisphere stratosphere temperatures are\nbeing monitoring from both rocketsonde and radiosonde data.\nFigure 3 shows the variation in year-average temperature in the\n46-55, 36-45 and 26-35 km layers through 1979, as obtained from\nrocketsonde data mostly in the western quadrant of the Northern\nHemisphere. Shown at the bottom part of Figure 4 is the\nvariation in year-average temperature in the 16-24 km layer\nthrough 1980 based on radiosonde observations throughout the\nNorthern Hemisphere. The temperature variations shown by the two\nsets of data are not in agreement, but since different altitudes\nare involved, there is not necessarily an inconsistency.\nThe radiosonde data for the 16-24 km layer show clearly the\nwarming following the eruption of Agung, but little overall\ntemperature variation thereafter. The rocketsonde data, on the\nother hand, show a large temperature decrease between 1970 and\n1976, with only a hint of a warming thereafter. It is noted that\nthe relatively warm temperatures of 1969 and 1978 in the 26-55 km\nlayer were near times of sunspot maxima but it is still too early\nto say there is a relationship between sunspot number and\ntemperature in middle and upper stratosphere. It is emphasized\nthat the cooling illustrated by rocketsonde data is much too\nlarge to be associated, in toto, with a CO 2 effect.\nII. OZONE MONITORING\nA. Trend Analysis of Data from the Global Ground-Based\nOzone Monitoring Network\nBecause of the possible impact on the earth's ozone\nshield of chlorofluorocarbons and other anthropogenic emissions,\ncareful analysis of total ozone data (the total amount of ozone\nin a vertical column above a given point on the earth's surface)\nis of importance. Total ozone data, as collected by the World\nOzone Data Center, Toronto, Canada, are analyzed for the five\n- 26 -","Northern Hemisphere Layer-Mean Temperature\n6\n5\nSS MAX\nSS MAX\n4\n3\n2\n1\n46 -55 - km\n0\nROCKETSONDE\n1\n--2\n-3\n-4\n2\n1\n36 - 45 km\n0\ni\nROCKETSONDE\n-1\n-2\n2\n1\n26 - 35 km\n0\nROCKETSONDE\ni\n-1\n-2\n1\n16 - 24 km\n0\nRADIOSONDE\n-1\n-2\nAGUNG\nFUEGO\n-3\n1960\n1965\n1970\n1975\n1980\nFigure 3. Variation in year-average temperature in stratospheric layers\nof the Northern Hemisphere, from rocketsonde and radiosonde\nmeasurements : Arrows labelled SS MAX indicate year of maximum\nsunspot activity.\n- 27 -","regions in the north temperate climate zone with adequate\ncoverage from instrumented ground sites (North America, Europe,\nSoviet Union, Japan and India). Total ozone is also analyzed for\nthe other four climate zones, and totals for each hemisphere and\nthe world are calculated from all ground-based data sources.\nFigure 1 (See Summary of Findings) shows the variation in year\naverage total ozone from 1958 through 1980 for each hemisphere\nand the world total, expressed as a percentage deviation from the\nmean. The vertical bars are confidence limits such that there is\nabout a 95 per cent chance that the true value of the mean lies\nwithin the extent of these bars.\nIn the mean for the world, the total ozone amount was\nobserved to be a significant 2.2 percent above average in 1979,\nand a non-significant 0.3 percent above average in 1980, where\nthe average is based on the years 1958-1977. All regions in the\nnorth temperate climatic zone and all four other climate zones,\nwhich showed an increase in total ozone between 1978 and 1979,\nregistered a decrease in total ozone between 1979 and 1980. (It\nis noted that the relatively high total ozone values in 1958,\n1970 and 1979 are near times of sunspot maxima, but it is still\ntoo early to say there is a relationship.) There is little\nevidence of a significant trend in total ozone during the 1970's\nfor either hemisphere or for the world.\nPhotochemical modeling predicts that the largest percentage\nof ozone depletion from chlorofluorocarbon releases would occur\nnear the 40 km level, and hence anthropogenic effects might first\nbe noted near this level. Crude estimates of the ozone\nvariations at these heights can be obtained by the Umkehr\nobservation method on the Dobson spectrophotometers. Figure 2\n(See Summary of Findings) shows year average values obtained by\nthis method for north temperate latitudes, this being the only\nclimatic zone with adequate data (observations in Europe, Japan,\nIndia, and recently, North America). The Umkehr data are\npresented for stratospheric height-layers 32-48 km, 24-32 km, and\n16-24 km. For comparison, ozonesonde data are presented for\nheight layers 24-32 km and 16-24 km based on observations in\nNorth America, Europe, and until recently, Japan.\nIn the critical 32-48 km layer the short-term Umkehr-\nindicated decrease in ozone following the volcanic eruptions of\nMt. Agung and Fuego is believed to be mostly an instrumental\nartifact due to errors introduced by stratospheric aerosols of\nvolcanic origin. The magnitude of the ozone increase since the\nFuego eruption (presumably due to fallout of the aerosols)\nimplies that there has been little ozone change in this layer\nsince 1970, with the 1979 value a significant 4.3 percent above\naverage and the 1980 value a non-significant 2.9 percent above\naverage, where the average is based on the years 1961-1977. In\nboth 16-24 km and 24-32 km layers the Umkehr data suggest\n- 28 -","essentially no change in ozone amount since 1970, whereas the\nozonesonde data suggest overall a slight ozone decrease. Thus,\nwe cannot be sure of the actual ozone trend in these two layers\nduring the past decade. Detection of a trend is made difficult\nby the strong quasi-biennial oscillation of ozone in 16-24 and\n24-32 km layers.\nU.S. Dobson Spectrophotometer Ozone Monitoring\nB.\nDobson spectrophotometer total ozone observations have\nplayed an important role in recent years in ozone trend\nanalyses. Such observations, in addition, provide \"ground truth\"\ndata for ozone observations made with satellite borne\ninstrumentation. During 1980 and 1981, the Air Resources\nLaboratories continued to monitor total ozone at the twelve U.S.\nDobson spectrophotometer stations. A list of the station\nlocations, showing the available ozone record, is given in Table\n1. Observations at Tallahassee, Florida, which were temporarily\ndiscontinued in 1979, were resumed in October, 1981.\nRecently, a least squares fit autoregressive trend model has\nbeen used to derive ozone trend data for North America for the\ntime interval 1961 through 1980. Data used were provisional\nmonthly mean total ozone values published by the World Ozone Data\nCentre in Canada. Included were 1980 Canadian and U.S.A. total\nozone data submitted for publication but not yet published.\nResults of the analyses shown in Table 2 and Figure 4 confirm\nearlier findings that ozone increased over North America during\nthe 1960's but decreased over North America during the 1970's\nThe decrease for North America is larger than for any other\nregion in the world. The reason for this difference is not\nknown.\nIn assessing the accuracy of total ozone measurements made\nwith Dobson spectrophotometers, a possible 5% systematic error\nwas investigated. It appears that it is due to use of an\nerroneous ozone absorption coefficient for the short wavelength\nof the Dobson instrument A wavelength pair. In related research,\nthe effect of interfering trace gas pollutants on the accuracy of\nDobson instrument ozone measurements was studied. Potentially\nsignificant interferers were found to be SO 2 and NO2. Trace gas\nspecies having absorption spectra at the Dobson instrument\nwavelengths but presenting insignificant interference were\nidentified to be N205, H2O2, HNO3, acetaldehyde, acetone, and\nacrolein.\n- 29 -","Table 1- 1980 U.S. Dobson Ozone Spectrophotometer Station Network\nPeriod of Record\nInstrument\nAgency\nStation\nNumber\nNOAA/NWS\n010163-present\n33\nBismarck, N. Dakota\nNOAA/NWS\n010163-present\n34\nCaribou, Maine\n42\nNOAA/GMCC\n121975-present\nTutuila Is., Samoa\nNOAA/GMCC\n010264-present\n63\nMauna Loa, Hawaii\nNOAA/NASA\n070167-present\n38\nWallops Is., VA\n76\nNOAA/GMCC\n080273-present\nBarrow, Alaska\nNOAA/NWS\n010163-present\n79\nNashville, Tenn.\n090166-present\n82\nNOAA/GMCC Hq.\nBoulder, Colorado\n86\nNOAA/Dept.\n010572-present\nWhite Sands, N. Mexico\nof Army\n58\nNOAA/Fla.\nTallahassee, Florida\n050273-053179\nState Univ.\n87\nNOAA/Huancayo\n021464-present\nHuancayo, Peru\nObservatory\nAmundsen-Scott,\n80\nNOAA/GMCC\n120563-present\nAntarctica\n- 30 -","Trends are expressed in percent ozone change per decade. Indicated trend uncertainties are 958 confidence level standard\n71-80\n-3.3\n+2.45\n-1.76\n+2.08\n-4.27\n+3.88\n-2.02\n+3.85\n-3.88\n+3.82\n-4.29\n+3.05\n1.17\n+2.77\n-1.91\n+3.18\n-0.14\n+2.99\n-2.3\n+1.1\nerrors. (Combined trends have been computed without regard to the statistical homogeniety of the various datra sets,\n-\n70-79\n-3.7\n+2.12\n-4.49\n+2.55\n-2.78\n+3.98\n-2.36\n+2.73\n-3.41\n+4.25\n-3.29\n+2.44\n-0.61\n+2.79\n0.88\n+5.32\n0.24\n+3.11\n-2.2\n+1.1\n69-78\n-3.94\n+2.18\n-9.12\n+3.30\n-3.58\n+2.79\n-7.58\n+3.12\n-4.02\n+4.02\n-1.41\n+1.90\n-4.88\n+3.11\n-2.13\n+5.18\n-0.72\n+3.44\n-4.2\n+1.1\n68-77\n-2.81\n+2.13\n-5.63\n+2.51\n-1.34\n+2.98\n-10.77\n+4.24\n-1.78\n+3.75\n-2.61\n+2.56\n-1.21\n+3.61\n-0.46\n+4.33\n4.00\n+3.81\n-2.5\n+1.1\n67-76\n2.46\n+2.62\n-6.48\n+2.99\n-4.34\n+3.77\n-6.15\n+4.02\n-0.61\n+3.07\n-1.93\n+3.11\n-0.68\n+2.23\n-4.07\n+5.64\n0.63\n+2.72\n-3.1\n+1.2\nTable 2. Running Ten-year Linear Ozone Trends Derived from\nNorth America Dobson Spectrophotome ter Total Ozone Data\n66-75\n-2.45\n+2.65\n2. Above results have been derived from autoregressive model ozone trend analyses.\n-1.14\n+2.52\n-3.17\n+3.34\n-.284\n+3.37\n2.77\n+2.98\n3.96\n+2.70\n-0.17\n+2.11\n1.22\n+3.99\n1.18\n+2.93\n-0.1\n+1.0\n65-74\n-0.91\n+2.47\n-1.85\n+2.31\n-3.88\n+3.86\n-1.90\nPeriods of Record\n+3.81\n-1.24\n+2.58\n6.36\n+4.09\n1.59\n+2.22\n3.29\n+4.43\n1.24\n+2.76\n0.3\n+1.1\n- 31 -\n64-73\n-0.37\n+2.48\n-0.07\n+2.04\n-0.51\n+2.25\n-3.02\n+2.93\n5.73\n+4.29\n1.96\n+2.63\n-0.37\n+5.11\n-2.48\n+2.72\n0.1\n+2.8\n63-72\n1.49\n+2.23\n0.17\n+3.33\n-1.13\n+3.21\n8.37\n+4.26\n0.94\n+3.21\n-0.67\n+5.33\n0.16\n+3.03\n1.3\n+1.4\n62-71\n-0.34\n+3.35\n8.26\n+3.99\n0.52\n+4.59\n-0.19\n+2.73\n2.1\n+1.9\n61-70\n1.45\n+3.51\n4.35\n+4.71\n0.11\n+2.93\n2.0\n+2.2\n60-69\nand may require modification.)\n5.70\n+3.67\n2.21\n+3.91\n4.01\n+3.18\n4.0\n+2.1\n59-68\n5.77\n+3.99\n3.93\n+4.04\n4.8\n+2.8\n58-67\n0.04\n+3.28\n2.15\n+3.86\n1.1\n+2.5\nChurchill\nGoose Bay\nNashville\nEdmonton\nSTATION\nResolute\nBismark\nCombined\nBoulder\nCaribou\nToronto\nTrends\n1.","80\nThe vertical bars represent 95 percent confidence levels (see Table 2).\nFigure 4. Ozone variations in percent per decade over North America since 1957.\n78\n76\n74\n72\n70\n- 32 -\nYEAR\n68\nValues above the zero line indicate\n66\nincreasing ozone: negative values\n64\nindicate decreasing ozone.\n62\n60\n58\n1-\nT\nIS\n5\nM\n2","A program to monitor long-term variations in ozone vertical\ndistribution by the Umkehr method is continuing in Boulder,\nColorado. The program goal is ozone trend detection at\napproximately 40 km altitude ( 2.8 mb ) where photochemical theory\npredicts that the greatest percent change in ozone will occur due\nto ozone depletion by chlorofluorocarbons.\nTwo projects are currently under way to develop improved\ninstrumentation for high altitude ozone vertical distribution\nmeasurements. The first entails automation of a Dobson\nspectrophotometer for Umkehr observations. Use of automatic\ninstruments for such observations would result in an increase in\nthe frequency of such observations, as well as in data that are\nnot observer biased. The second involves adaptation and testing\nof the electrochemical concentration cell (ECC) balloon\nozonesonde for high altitude ozone soundings up to 40 km.\nAutomation of Dobson spectrophotometer No. 61 is nearing\ncompletion. Results of comparison Umkehr data obtained in\nBoulder on 19 September 1981 with the automated Dobson instrument\nside by side with the manually operated world standard Dobson\nspectrophotometer No. 83 are shown in Figure 5.\nAdapting the ECC ozonesonde for high altitude soundings has\nentailed improving the sonde pump efficiency at altitudes above\n10 mb, checking instrument performance characteristics such as\nthe sensor background current, and developing a reliable,\ninexpensive balloon vehicle for reliable height attainment to\nflight altitudes of 40 km. About 50 percent success has been\nachieved in obtaining desired flight altitudes using 4000 g\nrubber balloons. This frequency of success has been, however,\ndeemed insufficient. As a result, tests are currently underway\nwith lightweight (0.23 mil plastic) balloons capable of bearing\nthe sonde flight packages to 40 km altitude. Two flights with\nplastic balloons have been made to date, both successfully\nattaining a flight altitude of 40 km.\nC. Upgrading the Global Dobson Spectrophotometer Network\nThe Air Resources Laboratories continued a program\nbegun in 1977 to upgrade, under auspices of the WMO Global Ozone\nResearch and Monitoring Project, the Dobson ozone\nspectrophotometers operated by other nations. In 1979, the NOAA\nDobson Instrument No. 83 at Boulder, CO, was designated by the\nWMO as the Primary Standard total ozone measuring instrument for\nthe world. In 1980, the WMO designated the Boulder Air Resources\nLaboratories (GMCC Program) as the World Central Laboratory for\nDobson spectrophotometer calibrations.\n- 33 -","1\nCOMPARISON \"SHORT\" UMKEHR OBSERVATIONS\n45\nBOULDER, CO SEPTEMBER 19, 1981 A.M.\nWORLD STANDARD DOBSON INSTRUMENT 83\n2\nAUTOMATIC DOBSON INSTRUMENT 61\n40\nTOTAL OZONE: 292 MILLI-ATMO-CM\n5\n35\n10\n30\n40\n(90)\n20\n20\nug/q\nw\n25\nn\nD\nS\n10\nS\nw 50\n20\nR\na\n5\n100\n15\n200\n10\n1\n500\n5\n5\n.1\n.2\n1000\n0\n50\n100\n150\n200\n250\n300\nPARTIAL PRESSURE OF OZONE (umb)\nFigure 5. | Umkehr ozone profile obtained with automatic\nDobson instrument 61 and manually operated\ninstrument 83.\n- 34 -","Foreign Dobson spectrophotometers modernized and calibrated\nin 1980 and 1981 were Nos. 97 and 99 in Buenos Aires, Argentina;\nNo. 114 in Chachoeira Paulista, Brazil; No. 64 in Potsdam, German\nDemocratic Republic; and No. 41 in Bracknell, United Kingdom. To\ndate 40 instruments (see Figure 6) have been directly calibrated\nand 40 other instruments have been indirectly calibrated relative\nto World Standard Dobson Instrument No. 83. This total of 80\ninstruments represents a substantial fraction of the\napproximately 110 existing Dobson spectrophotometers, about 73 of\nwhich are currently in use for observations.\nTo standardize Dobson spectrophotometer operating and\ncalibrating procedures throughout the world, an \"Operations\nHandbook - Ozone Observations with a Dobson Spectrophotometer\"\nhas been prepared for the World Meteorological Organization.\nCopies of the handbook are available from the WMO in Geneva,\nSwitzerland, or from the World Dobson Spectrophotometer\nCalibration Center, Air Resources Laboratories, R329, Boulder,\nColorado 80303.\nDisparities Between Satellite-based and Ground-based\nD.\nTotal Ozone Measurements\nGround truth total ozone measurements have been\nextremely important as a check on satellite total ozone\nmeasurements, especially for detecting long term instrument\ndrifts. The Dobson spectrophotometer is the accepted instrument\nfor ground truth measurements. However, there exisits some\nambiguity in total ozone measured by the Dobson when different\nwavelength pairs are used. The wavelengths used on the BUV and\nSBUV satellite ozone sensors differ from those used by the\nDobson. A persistent bias of about 5% has been noted in\ncomparisons between the Dobson and satellite ozone\nmeasurements. A close examination of total ozone derived from an\nultraviolet transmission spectrum for every 0.2nm in the\nwavelength range between 298.1 and 319.5nm revealed variations in\ntotal ozone amounts on the order of +5%, yet these variations\nwere consistent with the differences seen between the satellite\nand Dobson measurements at the several discrete wavelengths used\nby these instruments. It is suspected that the Dobson might be\nin error by 5% (too high), and that the cause could be due to the\nuse of incorrect ozone absorption coefficients. However, a\nsatisfactory explanation has not yet been found. This error in\nabsolute value would not affect trend estimates.\n- 35 -","Spain\n120\nFigure 6. Calibration of global Dobson ozone spectrophotometers relative to World Primary Standard\nBank\n114\nArgentina\n99\nMexico\n98\nArgentina\nCaglian\n97\n48\nBrazil\n93\nVigna Di Valle\nOther\nDenmark\n47\n92\nPakistan\nSestol\n100\nNorway\n56\nMessina\nPhilippines\n46\n52\nMaples\nG6\nIceland\n50\nNorway\n14\nWest Germany\nNorway\n8\n104\n1979 Potsdaam International Comparisons\nRumania\nVaranas\n1978 Arosa International Comparisons\n55\nItaly\n121\n47\nBoulder\nSwitzerland\nHungary\nMt Abu\n94\n110\n54\n15\nKodaikanal\nBoulder\nEdmonton\nSwitzerland\nJapan\nCanada\n91\nPoland\nIndia\n- 36 -\n102\n45\n101\n84\nCzechoslovakia\nHuancayo\nChurchiti\nPoona\n87\nBelgium\n39\n40\n74\n60\nWhite Sands\nWest Germany\nNew Delhi\nResolute\nPortugal\n86\n36\n44\n59\n13\nBoulder\nSrinagar\nGoosebay\n82\nFrance\nFrance\n10\n85\n11\n18\nInstrument No. 83 maintained by NOAA.\nS Pole\n80\nNashville\nFrance\n79\n85\nAustralia\nSeychelles\nBarrow\n111\n76\n57\nUSA\nThailand\nWallops\nIsland\nLerwick\n80\n72\n32\nChina\n75\nNew Zealand\nBoulder\nSingapore\n65\n17\n7\nMauna Loa\nChina\n3\nBracknell\n63\n2\nTallahassee\nHohenpeissenberg\n58\nSamoa\n42\nBoulder\n38\nCarbou\n34\n101 Switzerland\n105 Australia\n110 Hungary\n108 USSR\n108 USSR\n77 Canada\n17 Canada\n116 Japan\nBismarck\n34 Polana\n71 GDR\n96 Egypt\n96 Egypt\n112 India\n64 GDR\n112 India\n41 U U\n33\n41 UK\nInformation","E.\nThe Short Umkehr Ozone Profile Technique\nAn improved, more rapid method of acquiring vertical\ndistribution profiles of ozone from the ground-base Dobson\nspectrophotometer has been developed in a joint Canadian-U.S.\neffort, designated as the \"short Umkehr\" method. The short\nUmkehr method requires zenith sky measurements on the A-, C-and\nD-wavelength pairs of the Dobson ozone spectrophotometer ranging\nover the solar zenith angle between 80 and 89 degrees. It has\nbeen shown in a theoretical-numerical study that such\nmeasurements contain as much information about the ozone profile\nas do the conventional Umkehr observations taken on the C-\nwavelength pair over the solar zenith angle between 60 and 90\ndegrees. The short Umkehr requires about one-third of the\nobserving time needed for the conventional Umkehr.\nThis reduced observing time gives the short Umkehr at least\nthree distinct advantages over the conventional Umkehr. First,\nthere is less chance that significant changes in the ozone\nprofile will occur during the course of the observation; second,\nthere is a better chance that the zenith sky will remain clear,\nand third, it costs less per Umkehr observation in terms of\nobserver time.\nA computer program for short Umkehr ozone profile data\nreduction builds upon the earlier work done on the conventional\nC-pair evaluation program with the addition of the optimum or\nmaximum likelihood inversion method. This method uses a priori\nozone profile information obtained from rocket and balloon\nozonesondes. The short Umkehr computer program has been\ncompleted and preliminarily tested using ozonesonde observations\ntaken concurrently with short Umkehr observation. It is\navailable for routine reduction of Umkehr measurements submitted\nto the World Ozone Data Center at Toronto. Comparisons between\nsatellite and Umkehr observations of ozone in the upper\nstratosphere suggest that the Umkehr may be a reliable ground-\nbased system for validating satellite measurements.\nF. Aerosol Errors in Umkehr Ozone Profile Measurements\nErrors in Umkehr ozone profiles caused by aerosol\nscattering and absorption are most strongly related to optical\ndepth, and to a much lesser extent to aerosol refractive index,\nsize distribution, and vertical profile in the troposphere.\nStratospheric aerosols cause considerably greater error than\ntropospheric aerosols. Because the aerosol error in ozone\nprofiles is mainly related to aerosol optical depth and in a\nsystematic and linear way, it is feasible to make a correction to\nthe ozone profile if tropospheric and stratospheric optical depth\nare known. Tropospheric optical depth is commonly obtained by\n- 37 -","sunphotometer measurements, but stratospheric aerosol optical\ndepth requires more sophisticated means for its measurement; some\npossible methods are lidar and satellite (SAGE) measurements or\ntransmission measurements from a remote mountaintop observatory\nsuch as Mauna Loa. Finally, the short Umkehr method seems to be\nless sensitive to atmospheric aerosols, as compared to the\nstandard method by nearly a factor of 2. The reasons are thought\nto be due to the shorter range of sun angle change needed for the\nshort Umkehr measurement, and curtailment of the measurement at\n89° solar zenith angle. Corrections to longterm series of Umkehr\nobservation affected by stratospheric aerosol have been\nestimated. These corrections show that the sudden decrease in\nupper stratospheric ozone following the eruptions of Agung and\nFuego were likely due to the effect of aerosols on the Dobson\nspectrophotometer measurements. Corrections are important when\nstratospheric aerosols are increased by volcanic eruptions.\nIII. MONITORING ERYTHEMAL ULTRAVIOLET RADIATION AT THE GROUND\nWith financial support by the Environmental Protection\nAgency, NOAA has maintained a network of Robertson-Berger meters\nto measure ultraviolet radiation from the sun during the past\neight years in collaboration with the Temple University Medical\nSchool. The current stations in the network appear in Table 3.\nThe instrument responds to sunlight in approximately the same\nwavelength range that human skin sunburns which, in turn, is\nthought to be similar to the wavelength range associated with\nskin cancer production. In addition, special Dobson\nspectrophotometers (the instruments used to measure total ozone)\nwere modified to respond to erythemal solar radiation, and were\noperated at Bismarck, ND, and Tallahassee, FL from 6-73 to 2-75.\nAn analysis of the response of the network sensors with the\nmodified Dobson instruments confirms the dependence of the ratio\nof their readings upon the elevation of the sun above the\nhorizon.\nClimatological maps of ultraviolet radiation (UV) for the\ncontiguous US were prepared and sent to the National Eye\nInstitute, NIH and the Ames Research Center, NASA. The maps were\nconstructed from regression equations which related monthly\naverages of R-B UV-B radiation to global. solar radiation and\ntotal ozone. The equations were used to generate climatological\nUV amounts from the climatological record of solar radiation\n(1952-1976) and ozone (1958-1978).\n- 38 -","TABLE 3\nSTATIONS REPORTING ERYTHEMAL UV RADIATION\n1980-1981\nU.S.\nAlbuquerque, NM\nMinneapolis, MN\nAtlanta, GA\nNew Orleans, LA\nBismarck, ND\nOakland, CA\nDes Moines, IA\nPhiladelphia, PA\nDetroit, MI\n(Two Recorders)\nEl Paso, TX\nPt. Barrow, AK\nFt. Worth, TX\nRockville, MD\nGainesville, FL\nSalt Lake City, UT\nHoneybrook, PA\nSeattle, WA\nHouston, TX\nTallahassee, FL\nLa Jolla, CA\nTucson, AZ\nMauna Loa, HI\nNon-U.S.\nBasel, SWIZ\nHamburg, GER\nBelsk, POL\nHamilton, NZL\nBrisbane, AUS\nMelbourne, AUS\nDavos, SWIZ\nPanama, PAN\n- 39 -","The response of the Robertson-Berger sunburn meter is\ncalibrated empirically against the exposure of human skin to\nsolar ultraviolet radiation. The absolute uv energy of a sunburn\nunit in the human erythema band was not measured until the\npresent investigation. In an in-depth analysis, data from a\nRobertson-Berger (RB) erythema flux meter were compared with\nconcurrent measurements obtained with an ultraviolet\nspectroradiometer. It was found that at a solar zenith angle of\n30° one sunburn unit (SU) is equivalent to 35+4mJ-cm-2, and_at a\nsolar zenith angle of 69° one SU is equivalent to\n(relative to a wavelength of 297 nm), where the rate of change is\nnonlinear. The difference is due to the RB-meter's imperfect\nsimulation of the response of human skin to the incident\nultraviolet solar spectrum. Moreover, the rate of growth of the\ndeviation with increasing solar zenith angle was found to be 1.2%\nper degree between solar zenith angles 30° to 50° and 2.3% per\ndegree between solar zenith angles 50° to 70°. These deviations\nof response with solar zenith angle were found to be consistent\nwith reported RB-meter characteristics. The work now makes it\npossible to further utilize Robertson-Berger meter measurements\nin other fields of biological research, and in addition, chemical\nengineering involved with degradation of materials exposed to\nsolar ultraviolet radiation.\nIV. GROUND-BASED MONITORING OF CHLOROFLUOROCARBONS (CC13F AND\nCC12F2) AND NITROUS OXIDE (N20)\nChlorofluorocarbons are decomposed in the stratosphere by\nphotolysis, causing catalytic destruction of stratospheric ozone\nby released chlorine atoms. The major chlorofluorocarbons\nemissions are CC13F and CC12F2 from various human activities.\nNitrous oxide (N20) also enters into stratospheric photochemical\nreactions (involving NOX ) that lead to catalytic destruction of\nozone. Nitrous oxide is emitted from land by bacterial\ndenitrification of fixed nitrogen, as well as from combustion of\nfossil fuels for energy and heat.\nThe Air Resources Laboratories have been monitoring CC13F,\nCC12F2 and No since 1977. Data are obtained at Barrow (BRW),\nAlaska; Niwot Ridge (NWR), Colorado; Mauna Loa (MLO), Hawaii;\nAmerican Samoa (SMO), , South Pacific; and South Pole (SPO),\nAntarctica. Results of linear regression trend analyses of the\nmeasurement data are shown in Tables 4 and 5.\nNote the significant growth rates observed for CC13 and\nCC12F2. Minimum atmospheric lifetimes tentatively calculated for\nCC13F and CC12F2 are 41 and 65 years respectively. N2O also\nappears to be increasing at all stations.\n- 40 -","Mixing Ratio\n95% S.E.\n+0.51\n+0.65\n+0.52\n+0.49\n+2.54\n+1.09\n+1.26\n+1.16\n+0.68\n+1.72\nMixing Ratio\n172.9\n168.6\n163.8\n155.3\n157.0\n298.6\n295.9\n295.0\n273.1\n264.7\nPPTV\n4. Summary of CC13F and CC12F2 Measurement Results\nGrowth Rate\n95% S.E.\n+0.62\n+0.72\n+0.64\n+0.57\n+2.77\n+1.39\n+1.46\n+1.54\n+0.81\n+1.96\nGrowth Rate\nPPTV/Yr\n12.10\n10.78\n12.84\n12.35\n11.17\n15.10\n18.24\n18.97\n17.48\n17.93\n- 41 -\nObs.\nNo.\n133\n130\n128\n136\n42\n112\n58\n112\n118\n32\nStation\nBRW\nNWR\nMLO\nSMO\nSPO\nBRW\nNWR\nMLO\nSMO\nSPO\nTable\nStarting\n9/7/78\n(3 Yr)\n9/7/78\n(3 Yr)\nDate\nCC12F2\nTrace\nCC13F\nGas","Mixing Ratio\n95% S.E.\n+0.21\n+0.25\n+0.28\n+0.29\n+0.33\nN.H. - S.H. Conc.*: 301.1 - 299.4 = 1.9 PPBV\nMixing Ratio\n301.50\n301.78\n300.66\n303.17\n299.44\nPPBV\nGrowth Rate\n95% S.E.\nSummary of N2O Measurement Results\n+0.25\n+0.30\n+0.32\n+0.36\n+0.36\n- 42 -\nGrowth Rate\nPPBV/Yr\n0.43\n0.90\n0.88\n1.44\n0.44\nNo.\nObs\n143\n121\n136\n144\n63\nMean Growth Rate: 0.82 PPBV/Yr\nTable 5.\nStation\nBRW\nNWR\nMLO\nSMO\nSPO\n*Excluding SMO\nStarting\n7/1/79\n(3 Yr)\nDate","REFERENCES\nDave, J. V., C. L. Mateer, and J. J. DeLuisi, 1980: An\n1.\nexamination of the effect of haze on the short Umkehr\nmethod for deducing the vertical distribution of ozone,\nProceed. of the Quadrennial Internat. Ozone Symp.,\nBoulder, CO, 4-9 August 1980.\n2. DeLuisi, J. J. 1979: Shortened version of the Umkehr method\nfor observing the vertical distribution of ozone, Appl.\nOptics, 18, 3190-3196.\n3. DeLuisi, J. J., 1980: Disparities in the determination of\natmospheric ozone from solar ultraviolet transmission\nmeasurements 298.1 - 319.5 nm, Geophys. Res. Lett., 7,\n1102-1104.\n4. DeLuisi, J. J. and J. M. Harris, 1981: Characteristics of\nultraviolet radiation in the human erythema band\nmeasured with a Robertson-Berger meter and a double\nmonochromator, NOAA Tech Memo, ERL ARL-99, 43 pp.\nKomhyr, W. D. (1980), \"Dobson Spectrophtometer Systematic\n5.\nTotal Ozone Measurement Error\", Geophysical Research\nLetters, 7, No. 2, 161-163\n6. Komhyr, W. D., and R. D. Evans (1980), \"Dobson\nSpectrophotometer Total Ozone Measurement Errors Caused\nby Interfering Absorbing Species in Polluted Air, Such\nas SO2 and NO2, and Photochemically Produced 03\",\nGeophysical Research Letters, 7, No. 2, 175-160.\n7. Komhyr, W. D. (1980), \"Operations Handbook-Ozone\nObservations with a Dobson Spectrophotometer\", WMO\nGlobal Ozone Research and Monitoring Project, WMO\nReport No. 6, 125 pp.\n8. Mateer, C. L. and J. J. DeLuisi; 1980: The estimation of\nthe vertical distribution of ozone by the short Umkehr\nmethod, Proceed. of the Quadrennial Internat. Ozone\nSymp., Boulder, CO, 4-9 August 1980.\nMateer, C. L. and J. J. DeLuisi, 1980: The short Umkehr\n9.\nmethod, Part I: Standard ozone profiles for use in the\nestimation of ozone profiles by the inversion of short\nUmkehr observations, NOAA Tech Memo, ERL, ARL-86, 20\npp.\n- 43 -","10. Komhyr, W. D. , R. D. Grass and R. K. Leonard (1981), \"WMO\n1977 International Comparison of Dobson Ozone\nSpectrophotometers\", in Proceedings of the Quadrennial\nInternational Ozone Symposium, Boulder, Colarado, 4-9\nAugust 1980, Julius London, Editor, Vol. I, pp 27-32\n11. Komhyr, W. D. , R. D. Grass, R. D. Evans and R. K. Leonard\n(1981), \"Dobson Spectrophotometer Calibrations,\nPossible Errors in Ozone Absorption Coefficients, and\nErrors Due to Interfering Pollutant Gases\", in\nProceedings of the Quadrennial International Ozone\nSymposium, Boulder, Colarado, 4-9 August 1980, Julius\nLondon, Editor, Vol. I, pp 230-235.\n12. Oltmans, S. J. (1981), \"Surface Ozone Measurements in Clean\nAir\", J. Geophys. Res. 86, 1174-1180.\n13. Komhyr, W. D. , R. D. Grass, E. G. Dutton and R. K. Leonard\n(1981), \"Trend Determinations from Provisional and\nCorrected 1963-1979 Bismarck Total Ozone Data\", in\nProceedings of the Quadrennial International Ozone\nSymposium, Boulder, Colarado, 4-9 August 1980, Julius\nLondon, Editor, Vol, I, pp 371-377.\n14. Oltmans, S. J. , and J. London (1981), \"The Quasi-Biennial\nOscilation (QBO) in Atmospheric Ozone\", in Proceedings\nof the Quadrennial International Ozone Symposium,\nBoulder Colarado, 4-9 August 1980, Julius London,\nEditor, Vol. I, pp 397-405.\n15. Komhyr, W. D. T. M. Thompson, and E. G. Dutton (1981),\n\"Chlorofluorocarbon -11, -12, and Nitrous Oxide\nMeasurements at the U.S. GMCC Baseline Stations (16\nSeptember 1973 to 31 December 1979)\" approved for\npublication as a NOAA Technical Report.\n- 44 -","GEOPHYSICAL FLUID DYNAMICS LABORATORY (GFDL)\nPrinceton, New Jersey\nChanges in atmospheric trace constituents and the climatic\neffect of such changes cannot be detected or understood without a\nfirm knowledge of the processes which maintain and alter the\nnormal state. Although such detailed knowledge is gradually\naccumulating, a number of important gaps and deficiencies remain\nat the end of 1981. Further progress requires continued\nintensive research efforts for a number of years to come.\nBasic research conducted to improve the understanding of the\ngeneral circulation of the atmosphere, including the\nstratosphere, has been underway at GFDL for over 20 years. The\nmiddle atmosphere research effort was accelerated in 1970 when a\ncommitment was made to concentrate specificially on the\nstratosphere. The summary of stratospheric research performed at\nGFDL since January 1980 builds on the considerable base\nconstructed prior to that date.\nListed below are summaries of the 1980-1981 progress in\nvarious GFDL research activities related to the atmospheric ozone\nproblem and its potential climatic impact.\nI.\nTHREE-DIMENSIONAL MODELING OF TRACE CONSTITUENT BEHAVIOR\nA number of problems have been explored since 1979 dealing\nwith the transport and chemistry of trace constituents, using one\nof the GFDL global 3-D general circulation models (GCM) (e.g.,\nManabe, Hahn, and Holloway, 1974; Manabe and Mahlman, 1976) to\nprovide self-consistent, time dependent winds.\nA. Atmospheric N2O Experiments\nAnalysis has continued on a number of 3-D experiments\nsimulating the behavior of atmospheric N 0. The first experiment\nassumed the surface emission of N2 O to be horizontally uniform.\nIn the second experiment the surface source is removed completely\n(\"No Source\") . In a third experiment the surface source is\nallowed to emanate only from land areas with rainy climates\n(\"Swamp Source\"). Here the global source strength is the same as\nin the first experiment.\nResults from the \"No Source\" N20 experiment show indirectly\nthat the lower tropospheric variability is strongly influenced by\nthe local intensity of the surface source, while the downward\nflux of smaller values of N2O from the stratosphere plays a\nlesser role. For the \"Swamp Source\" experiment, the surface\nlayer concentrations and variabilities are strongly influenced by\nthe locations of the source regions. This result provides a\n- 45 -","powerful tool for determination of the source locations and\nstrengths in the actual atmosphere. Details are given in Levy\nand Mahlman (1980).\nThrough further analysis, it was determined that, while\nspatial variability in the boundary layer is strongly dependent\non the surface structure, spatial variability in the middle\ntroposphere and above is controlled by large-scale vertical\ntransport. The results of this work also apply to most long-\nlived trace gases (see Levy, Mahlman, and Moxim, 1981).\nIn addition, a series of experiments investigating the\nsensitivity of the stratospheric N2O distribution to various\ndestruction hypotheses is underway. These experiments have\nindicated a remaining deficiency in the current state of\nquantitative modeling of stratospheric N O: the use of currently\naccepted, slower N 2 0 destruction rates in the model does not\nproduce the best agreement with observations. Faster\nstratospheric destruction rates are required. Preliminary\nresults from this research are available in Levy, Mahlman, and\nMoxim (1980b).\nB. Reactive Nitrogen in the Troposphere\nOne of the problems in tropospheric chemistry receiving\nattention is that of the budget of reactive nitrogen. This\nquantity is produced by anthropogenic processes at the ground\n(combustion) and aloft (aircraft) as well by the stratospheric\ndestruction of N20. Reactive nitrogen is destroyed primarily\nthrough heterogeneous removal in the form of nitric acid.\nTo explore the possible role of the stratospheric reactive\nnitrogen source, the results of a previous tracer experiment by\nMa hl ma n, Levy, and Moxim (1980) were scaled by using the N 2 O\nfields calculated in the above experiments. The analysis\nindicates that the stratospheric reactive nitrogen dominates the\nupper troposphere, and may be significant in regions of the lower\ntroposphere far removed from pollution sources. (Levy, Mahlman,\nand Moxim (1980a).\nA series of model experiments has been started which examine\nthe large-scale spreading and deposition of reactive nitrogen\nproduced by surface combustion (the nitric acid contribution to\n\"acid rain\"). These experiments also examine the impact of the\nU.S. combustion source on the global nitrogen budget. During\nFY81, a series of short exploratory experiments were run to\nexamine the effects of both rainout removal and surface\ndeposition on the global influence of the U.S. source.\nPreliminary results indicate that, while combustion nitrogen is\ndistributed throughout the Northern Hemisphere, the stratospheric\nsource still dominates above 500 mb. The relative contributions\nof the stratospheric source and the combustion source below 500\nmb remain uncertain.\n- 46 -","C.\nA Revised Hypothesis for the Origin of Tropospheric\nOzone\nThe results from the above N 2 O and reactive nitrogen\nexperiments, combined with recent nitric oxide measurements\nconducted by members of the Aeronomy Laboratory, have led to\na\nstrongly altered view of the behavior of ozone in the\ntroposphere. Tropospheric ozone has previously been thought to\nbe either transport-controlled by flux from the stratosphere or\nphoto-chemically controlled by ozone sources and sinks near the\nsurface. The new view, which arose out of a collaboration with\nscientists from the Aeronomy Laboratory, seems to explain\ndifficulties with both previous views. Calculations indicate\nthat photochemical ozone production, initiated by reactive\nnitrogen transported downward from the stratosphere, can produce\nas much or more ozone than is provided by the direct ozone\nflux. The added sink of ozone required is found in the lower\ntroposphere by way of a water vapor related destruction path.\nDetails may be found in Liu, et al. (1980).\nOne implication of this work is that significant ozone\nproduction due to subsonic aircraft emissions of reactive\nnitrogen could occur. Interestingly, analysis by Air Resources\nLaboratory members of available ozonesonde records (mostly from\nother countries) indicate an upper tropospheric ozone increase\nwhich is not inconsistent with those calculated.\nFurther research in this area is imperative because of the\ndirect climatic effect of increased tropospheric ozone due to\nenhancement of the \"greenhouse\" blocking of tropospheric infrared\nradiation.\nD.\nExamination of the Classical Theory for Tropospheric\nOzone\nThe above work has led to an intensified interest in\nthe understanding of tropospheric ozone. Because of the\ndifficult and controversial nature of the subject, it was decided\nthat a more basic understanding of the various components of the\ntropospheric ozone budget is required. Accordingly, an effort\nwas made to examine the classical hypothesis that ozone brought\ndown from the stratosphere is chemically inert and is removed\nfrom the atmosphere by contact with the earth's surface. The\nlimits of remaining uncertainty in surface ozone removal have\nbeen explored through use in the model of high and low extremes\nin the surface removal rates. Interestingly, the results show\nthat available observations are well bracketed by these\nexperiments. Whether this means a reduced role for in situ ozone\nchemistry in the troposphere remains to be determined.\n- 47 -","E. Review of Stratospheric Trace Constituent Transport\nAs part of a commitment to the Middle Atmosphere\nProgram (MAP), a comprehensive review has been written for the\nfirst time on the problem of transport of trace constituents in\nthe stratosphere. The review covers: the history of various\nviewpoints, relevant observations, a unified theoretical\nframework, available methodologies, parameterized transport\nhypotheses and future research requirements (MAP Study Group 2,\n1981).\nF. \"Maximum Insight\" Tracer Experiments\nIn recent years, there has been a growing interest in\nLagrangian-oriented transport analysis methods as possible keys\nto clarify understanding of transport phenomena. In response to\nthis, an effort is underway to formulate tracer experiments and\nanalyses that seek to maximize physical understanding. For\nexample, insights into some transport problems can be simplified\nif viewed in isentropic coordinates. To exploit the isentropic\ncoordinate analysis techniques developed in FY81, two simplified\ntracer experiments have been designed. The first is initialized\nwith the chemically inert tracer mixing ratio set equal to the\npotential temperature, the second with the tracer prescribed as a\nconstant plus the latitude.\nThese experiments have revealed, in a very simple way, the\nessential features responsible for the pronounced downward slope\nof mixing ratio isolines toward the pole in the stratosphere.\nIn\nparticular, the equilibrium tracer slope appears as a balance\nbetween (1) the slope-steepening diabatic circulation, moving\nmass downward (upward) through the isentropic surfaces in high\n(low) latitudes, and (2) the direct effect of disturbances\npropagating into the stratosphere, producing slope-flattening\ndown-gradient mixing along isentropic surfaces.\nStratospheric Aircraft Pollution Experiment\nG.\nAn experiment was begun in FY77 in an attempt to\nsimulate the 3-D dispersion of gaseous effluents from an\nidealized fleet of stratospheric supersonic aircraft. Although\nthe experiment has been run on a low-priority basis only since\nFY77, it has now been integrated out to equilibrium. Analysis of\nthe results has begun.\nII. MODELING OF THE TROPOSPHERE-STRATOSPHERE-MESOSPHERE SYSTEM\nFor the past 6 years, an effort has been underway to develop\na comprehensive, three-dimensional general circulation model\n(GCM) of the radiative-chemical-dynamical structure of the\n- 48 -","atmosphere from the earth's surface to the me sopause. A major\ngoal of this research is to develop an internally consistent\ncapability for simulating ozone and its changes. Activities\nunder this program since 1979 are summarized below.\nLow Resolution (N10) Annual Cycle Experiment\nA.\nThe low resolution (N10, (9° lat. by 10°long.) GCM has been\nrun out to 3 years. The indication of a semiannual oscillation\n(SAO) reported previously has been sustained. This SAO appears\nto be quite realistic in the upper stratosphere. The basic model\nmechanisms for this SAO are as follows. The westerly phase is\ngenerated more or less continuously by momentum deposition from\nupward and eastward propagating equatorial Kelvin waves, the\nlargest deposition of westerly momentum just below the maximum of\nthe westerly wind. The \"maximum entropy\" technique used to\nobtain this result also has revealed the presence of so-called\n\"fast\" Kelvin waves near the model equatorial stratopause. The\nsource of these waves has yet to be determined, but such waves\nhave not been identified below 30 km in the model or in\nobservations.\nThe westerly flow produced by that mechanism is interrupted\ntwice a year by strong cross-equatorial flow producing advection\nof easterly momentum from the summer hemisphere. The cross-\nequatorial flow is excited by the unbalanced pressure gradient\nproduced by differential heating between the summer and winter\nhemisphere. These results are described in Mahlman and Sinclair\n(1980).\nFor purposes of evaluating the climatic sensitivity of the\nstratosphere, it is of interest to know whether the inclusion of\nthe annual cycle is essential. The annual average statistics\nfrom this experiment have been compared against the statistics\nfrom this annual-mean-insolation experiment of Fels, et al.\n(1980). The results show the two sets of statistics to be very\nsimilar. This suggests that stratospheric climate sensitivity\nexperiments might be run successfully using the simpler annual-\nmean-insolation models.\n\"Low Diffusion\" Medium Resolution (N18) Experiment\nB.\nAnalysis of previous experiments with this model, as\nwell as comparisons with other finite difference and spectral\nmodels, led to the inference that low resolution finite\ndifference models were unnecessarily diffusive. As a way of\nexploring this conjecture, the horizontal non-linear diffusion\ncoefficient has been altered by reducing the multiplicative\nconstant by a factor of three, while increasing the scale\nselectivity of the horizontal deformation operator. This change\nwas applied to the N18 annual me an control model.\n- 49 -","The alteration has had a number of significant effects. The\ntropospheric subtropical jets are significantly stronger, while\nthe tropical upper tropospheric winds are much less westerly. An\neasterly acceleration is induced in the tropical middle\nstratosphere. The most dramatic effect, however, is that the\nmid-latitude mesospheric jets are reduced in magnitude and become\ncompletely closed of £ near their proper altitude. This behavior\nis related to an increased mesospheric mechanical dissipation\nresulting from the decreased horizontal diffusion. In this \"low\ndiffusion\" experiment, increased wave activity is allowed to\nleave the troposphere and propagate upwards. The larger wave\namplitudes lead to an increased excitation of the model's low\nRichardson number turbulent dissipation in the mesosphere. The\ndissipating disturbances force the marked deceleration of the\nmesospheric zonal flow.\nC.\nModel Analysis Technique Development\nRecently, significant effort has been expended to\nformulate model analysis packages which provide exact and more\nphenomenologically oriented balance analyses (Andrews, Mahlman,\nand Sinclair, 1981). Utilization of these packages has led to\nthe diagnosis of a small code error which otherwise would have\ngone undetected. In addition, the new analysis procedures have\nproduced a clearer identification of the types of aliasing and\nsampling problems which result from analysis of model data taken\nat relatively infrequent time intervals.\nDuring FY81, an effort has also been underway to develop a\nmore accurate technique to analyze model transport and wave\ndynamics in isentropic coordinates. The technique development\nphase is nearing completion\nD.\nSimpler Models for the Interaction Between Waves and\nFlows\nThe effects of tidal motions on the general circulation\nof the middle atmosphere have been investigated. The heat and\nmomentum fluxes associated with the diurnal tide were computed\nusing separable tidal theory. These fluxes were used in turn to\nforce a simple axisymmetric model of the stratosphere,\nmesosphere, and lower ermosphere. The results showed that the\ntide may induce significant me an zonal winds ( 10-20 m/sec) in\nthe vicinity of the equatorial stratopause. In the lower\nthermosphere (80-90 km), the diurnal tide forces strong\neasterlies in the tropics and westerlies in mid-latitudes, in\napparent agreement with the observed zonal winds in this region\n(Hamilton, 1981).\n- 50 -","The simple, one-dimensional model of the quasi-biennial\noscillation (QBO) of the tropical lower stratosphere originally\ndevised by Holton and Lindzen has been investigated in some\ndetail. It was found that the behavior of this model is very\nsensitive to the details of the spectrum of waves which are used\nto force it and to the upper boundary condition employed. In\nparticular it is possible for the me an flow evolution in the\nmodel to be dominated by very long period ( >10 years)\noscillations if waves with phase speeds of 35 m/sec or greater\nare included.\nA two-dimensional quasi-biennial oscillation model has been\nconstructed which allows expansion of the above results. Unlike\nprevious mechanistic models, which have considered only the\nmeridionally averaged equations, the present version allows\ninvestigation of the latitudinal structure of the me an flow and\nof the waves which force the QBO.\nA number of integrations have been performed with this\nmodel. The results indicate the following conclusions: (1) A\nvertically propagating Kelvin wave with the observed wavenumber,\nphase speed and amplitude tends to force a westerly jet which has\na much narrower meridional scale than the observed westerly phase\nof the QBO. This problem can be alleviated by including a rather\nmodest amount of horizontal momentum diffusion in the me an flow\nequations. (2) When the Rossby-gravity wave is damped with only\nradiative cooling, the induced easterly accelerations are\ncentered off the equator in a very unrealistic manner. If\nmechanical dissiption of the wave is included, the accelerations\nbecome equatorially centered. However, inclusion of excessive\nmechanical dissipation (relative to the radiative dissipation)\ncauses the production of an unrealistically narrow easterly jet.\n(3) With appropriate parameters for the waves and me an flow, a\nsingle Kelvin wave and a single Rossby-gravity wave can produce\nalternating easterly and westerly regimes in the me an flow model.\nIII. MODELING OF RADIATIVE AND CHEMICAL PROCESSES\nA.\nComputation of Infrared Cooling Rates\nAn algorithm for computing accurate CO 2 15 micrometer\nband cooling rates has been completed, including the publication\nof detailed tranmission function tables (Fels and Schwarzkopf,\n1981).\nAn investigation of the effect of non-Lorentzian shape on\nthe CO 2 15 micrometer bands was begun, with two objectives: a)\nto assess the sensitivity of transmission functions to such\neffects; b) to discover the best empirical line shape by\ncomparison with high quality laboratory data.\n- 51 -","The comparison of line-by-line and suitable random model\nresults shows that the latter provide a fast way of assessing the\neffects of altered line shape on transmitivities. It has been\nfound that variation in line profile cutoff between 1 cm and 30\ncm alters the total CO 2 absorption by up to 5%.\nThe availability of excellent laboratory spectra at a large\nnumber of pressures and path lengths hasimade it possible to\ndetermine an effective cutoff, (3 cm ) which fits the bulk of\nthe data very well. With this value, calculated broad band\nintegrated absorptions agree with the measured values to within\n0.5% in most cases.\nB.\nrameterization of Scale-Dependent Radiative Damping\nRadiative transfer is not only important because it\ndrives atmospheric circulations, but also because it plays a\ncentral role in the damping of atmospheric temperature\ndisturbances due to infrared thermal emissions. The quantitative\ndescription of circulation, temperature, transport, and trace\nconstituent structure in the atmosphere are all strongly affected\nby such damping processes.\nGFDL general circulation models have traditionally\nincorporated sophisticated radiative transfer computations in\nwhich the infrared cooling rate at a given level depends on the\ntemperature not only at that level, but at all others as well.\nOn the other hand, the much simpler linear or mechanistic\ndynamical models generally use the so-called \"Newtonian cooling\"\napproximation. This approach makes radiative transfer\ncalculations trivial by assuming that the cooling rate depends\nlinearly on only the local temperature.\nDuring FY81, a method has been developed which allows the\neffects of radiative non-locality to be included easily in a wide\nclass of wave-dynamical problems (Fels, 1981). The manner in\nwhich a slowly modulated sinusoidal temperature perturbation is\naffected by radiative damping provides a way to define a scale-\ndependent generalization of the conventional Newtonian relaxation\ntime.\nWith the use of the accurate radiative transfer algorithms\ndeveloped previously (Fels, 1979; Fels and Schwarzkopf, 1981),\ncareful calculations of scale-dependent damping times have been\ncarried out for both the 15 micrometer bands due to CO 2 and the\n9.6 micrometer band due to O3. The results indicate that the\neffects of non-locality can be of great dynamical importance.\nFor example, a disturbance with a vertical wavelength of 10 km\nhas a purely radiative decay rate which is more than three times\nas large as that which would be calculated in the local Newtonian\ncooling approximation.\n- 52 -","C. Incorporation of Ozone Chemistry in the Global\nCirculation Model (GCM)\nThe collaborative effort with NOAA Aeronomy Laboratory\nscientists has now reached an advanced stage of development. The\nchemical code has been properly calculated in the GCM vertical\ncoordinate, including self-consistant temperature and density\neffects. The photochemically determined, implied shortwave\nheating rates are now very similar to those determined\nindependently from the GCM short-wave heating algorithm.\nThe codes now have the capability of calculating both\ndiurnal and diurnally averaged chemical equations. In addition,\nsteady-state or time-marching techniques are optional, depending\nupon the nature of the problem. This chemical model has been\nsuccessfully integrated with an off-line version of the GCM\nradiative transfer code.\nD.\nRadiative-Photochemical Interaction\nAlthough GFDL models have traditionally made use of\npre-specified ozone amounts in radiative calculations, the\ndetermination of ozone distributions from first principles\nremains an important long-range goal. A first step in this\ndirection is to gain an understanding of the coupling of\nphotochemistry and radiation in the absence of dynamical\nprocesses ( i.e., the determination of joint radiative-\nphotochemical equilibrium).\nIn collaboration with scientists of the Aeronomy Laboratory,\na model which combines that group's photochemistry (see Section 3\nabove) with the GFDL radiation code has been constructed. This\nmodel has been used to calculate radiative-photochemical\nequilibria in the middle atmosphere, as well as to investigate\nthe relaxation of ozone and temperature perturbations toward\nequilibrium. The results of these perturbation decay experiments\nsuggest that the photochemical enhancement of radiative damping\nmay be less important than scale-dependent radiation (see Section\n2 above) in damping middle atmospheric waves.\n- 53 -","REFERENCES\nAndrews, D. G. , J. D. Mahlman, and R. W. Sinclair, 1981:\n1.\nThe use of the Eliassen-Palm flux as a diagnostic of\nwave, mean-flow interaction in a general circulation\nmodel. Handbook for MAP, Vol. 2, Proceedings of the\nInternational Symposium on Middle Atmosphere Dynamics\nand Transport, 28 July - August 1980, Urbana, II, pp.\n99-100.\nFels, S. B., 1979: Simple strategies for inclusion of\n2.\nVoight effects in infrared cooling rate calculations.\nApplied Optics, 18, 2634-2637.\nFels, S. B. , 1981: A parameterization of scale-dependent\n3.\nradiative damping in the middle atmosphere. Submitted\nto J. Atmos. Sci.\nFels, S. B. , J. D. Mahlman, M. D. Schwarzkopf, and R. W.\n4.\nSinclair, 1980: Stratospheric sensitivity to\nperturbations in ozone and carbon dioxide: Radiative\nand dynamical response. J. Atmos. Sci., , 37, 2265-2297.\nFels, S. B. , and M. D. Schwarzkopf, 1981: An efficient\n5.\nalgorithm for calculating CO2 15 um band cooling\nrates. J. Geophys. Res., 86 (C2), 1205-1232.\nHamilton, K., 1981: Effects of atmospheric tides on the\n6.\ngeneral circulation of the stratosphere, mesosphere,\nand lower thermosphere. Handbook for MAP, Vol. 2.,\nProceedings of the International Symposium on Middle\nAtmosphere Dynamics and Transport, 28 July - August\n1980, pp. 246-255.\nLevy, H., II, and J. D. Mahlman, 1980: Modeling tropspheric\n7.\nN2O. Proceedings of the NATO Study Institute on\nAtmospheric Ozone: Its Variation and Human Influences,\n1-3 October 1979, Algarve, Portugal, A. C. Aiken (ed.),\nFFA-EE-80-20, pp. 893-907.\nLevy, H. II. , J. D. Mahlman, and W. J. Moxim, 1980a:\n8.\nStratospheric source of reactive nitrogen in the\nunpolluted troposphere. Geophys. Res. Lett., , 7, 441- -\n444.\n9. Levy, H. II., , J. D. Mahlman and W. J. Moxim, 1980b: A three\ndimensional numerical model of atmospheric N2O.\nProceedings of the Quadrennial International Ozone\nSymposium, Vol. II, 4-9 August 1980, Boulder, CO.\nInternational Ozone Commission (IOC), pp. 943-947\n- 54 -","10. Levy, H. II., J. D. Mahlman, and W. J. Moxim, 1982:\nTropospheric N2O variability. J. Geophys. Res., 87 (In\npress).\n11. Liu, S. C., D. Kley, M. McFarland, J. D. Mahlam, and\nH. Levy II, 1980: On the origin of tropospheric ozone.\nJ. Geophys. Res., , 85 (C12), 7546-7552.\n12. Mahlman, J. D. , Levy II, and W. J. Moxim, 1980: Three-\ndimensional tracer structure and behavior as simulated\nin two ozone precursor experiments. J. Atmos. Sci.,\n37, 655-685.\n13. Mahlman, J. D. , and R. W. Sinclair, 1980: Recent results\nfrom the GFDL troposphere-stratosphere-mesosphere\ngeneral circulation model. Proceedings of the\nInternational Union of Geodesy and Geophysics (IUGG)\nSymposium 18, Twenty-Seventh IUGG General Assembly,\nDecember 1979, Canberra, Australia, NCAR, Boulder, CO.,\n,\npp. 11-18.\n14. Manabe, S., D. G. Hahn, and J. L. Holloway, Jr., , 1974: The\nseasonal variation of the tropical circulation as\nsimulated by a global model of the atmosphere. J.\nAtmos. Sci. , 3, 43-83.\n15. Manabe, S. and J. D. Mahlman, 1976: Simulation of seasonal\nand interhemispheric variations in the stratospheric\ncirculation. J. Atmos. Sci, 3, 2185-2217.\n16. MAP Study Group 2 (J. D. Mahlman, Chairman) 1981:\nTransport of trace constituents in the stratosphere.\nHandbook for MAP, Vol.3 , C. F. Sechrist (ed.), pp. 15-\n44.\n- 55 -","SPACE ENVIRONMENT LABORATORY\nBoulder, CO.\nMONITORING SOLAR ULTRAVIOLET RADIATION FROM SATELLITE-AND\nI.\nGROUND-BASED INSTRUMENTS.\nThe Space Environment Laboratory (SEL) and the Air Resource\nLaboratories (ARL) began in FY 1980 a program to determine the\nnatural variability of solar ultraviolet radiation, one key\ndriving force in the climate of the earth. The Space Environment\nLaboratory project is being conducted in cooperation with NASA to\nmonitor solar ultraviolet radiation from satellite-based Solar\nBa ackscatter Ultraviolet ozone monitoring instruments (SBUV-2) now\nbeing built under a joint NOAA-NASA contract for flights on the\noperational NOAA (Tiros-N) satellites beginning with a NOAA G\nlaunch in 1985. The Air Resources Laboratories conduct ground-\nbased measurements to monitor the longer wave-length solar\nultraviolet radiation as well as optical and infrared solar\nradiation to provide ground - truth for the satellite\nmeasurements. ARL is already conducting research to improve\nunderstanding of the atmospheric effects of solar UV variability\nand to improve the precision and accuracy of the measurement\nsystems. Other ARL objectives include: to corroborate satellite\nmeasurements of the solar constant (a key factor in both the\nprecision of the Dobson ozone spectrophotomete measurements\nworld-wide and the earth's climate), to determine solar\nvariability as a function of wavelength, and to conduct research\nto understand the effects of solar UV variability, particularly\nin the portion of the spectrum involved in sunburning (erythemal)\neffects.\nThe objectives of the SEL project are to determine the\nvariability of solar ultraviolet radiation over time scales of\nmonths, years and decades; an understanding of why the solar UV\nflux varies and whether the variations can be predicted; and to\ndetermine the atmospheric reactions to solar ultraviolet\nvariations and the extent to which these reactions contribute to\nclimate variations.\nDuring 1980-1981, the SEL project has determined the\nwavelength dependence of olar-rotation variations (approximately\n27 days) of the solar UV flux in collaboration with NASA using\nNimbus 7 SBUV data. The Space Environment Laboratory in\ncooperation with the Cooperative Institute for Research in the\nEnvironmental Sciences of the University of Colorado has\ndeveloped models to explain these variations in terms of solar\nactive region structure and spatial location on the sun. The\nunderstanding of these short-term variations is necessary in\norder to interpret any long-term series of measurements from\nrocket or shuttle flights as well as the operational\n- 56 -","satellites. Also they help to interpret the solar ultraviolet\nvarriations over a solar cycle caused by the build-up of active\nregions on the sun and the chromospheric network. The long-term\nvarriations (years) recently observed by Nimbus 7 instrumentation\nare large enough to cause stratospheric changes, but\ncorroborating measurements and further study are necessary to\nverify that these are real solar variations and not due to\ninstrumentation problems. A program for developing a higher\naccuracy solar ultraviolet instrument for rocket flight\nmeasurements has been initiated. Rocket flight measurements of\nsolar UV radiation are needed to recalibrate the satellite\nmeasurements and to permit intercomparison of measurements from\nsatellites (Nimbus 7, Solar Mesosphere Explorer, and NOAA\noperational Tiros N SBUV-2) launched several year apart.\nThe Air Resources Laboratories portion of this program\nincluded a contract with the Institute for Atmospheric Physics\nand the Optical Sciences Center of the University of Arizona to\nconduct studies leading to improvements in the atmospheric\ncorrections for ground-based solar flux measurements and to\ndevelop improved instruments and a ground-based solar flux\nmonitoring program. Also the ARL is studying correlations of\nclimate variations in the United States with variations in solar\nflux to determine the degree of significance of such\ncorrelations.\n- 57 -","NATIONAL EARTH SATELLITE SERVICE\nSuitland, MD\nTHE TIROS OPERATIONAL SATELLITE VERTICAL SOUNDER\n1.\nCurrently, the NOAA operational TIROS-N type spacecraft are\nequipped with the TIROS Operational Vertical Sounder (TOVS). The\nTOVS sounders continue to obtain atmospheric radiance data for\nsubsequent inversion and derivation of total ozone amounts\nglobally. The sequence of NOAA satellites and their periods of\ncoverage are:\nTIROS-N: April 15, 1979 - January 25, 1981 (demise)\nNOAA 6:\nNovember 1, 1979 - Present\nNOAA 7 : August 15, 1981 - Present\nThe total column ozone monitoring capability of TOVS was\ndesigned not as a primary data source, but as a correction input\nto the temperature profiling subsystem. (The small influence of\nozone on several of the TOVS channels is large enough to require\ncorrection and an on-board measurement capability was designed\nfor this purpose.) However, the accuracy required for these on\nboard corrections is less than desired for a primary global ozone\nsatellite monitoring system. In addition, the present\noperational capability to derive total ozone data only does not\nprovide ozone profile data necessary for early warning purposes.\nII. DEVELOPMENT AND OPERATIONAL IMPLEMENTATION OF THE SATELLITE-\nBORNE SOLAR BACKSCATTER ULTRAVIOLET (SBUV/2) OZONE MONITORING\nSYSTEM\nThe design phase of the SBUV/2 being developed for future\nNASA research operational use is continuing. A major change from\nprevious instruments of this type will be the ability to command,\nin space, rotation of the gratings in order to change the\nwavelengths while in the operating mode. This will enable NOAA\nto insure a uniform wavelength setting on all of the instruments\nif any changes were noted to occur during and after launch.\nThe first SBUV/2 instrument is expected to become\noperational on the NOAA-G satellite currently scheduled for\nlaunch in 1985. (Any schedule of satellite launches is dependent\nupon unknown budget considerations.) It will be operated in\nseveral modes in a planned sequence in order to acquire a variety\nof data. These are:\nEarth view mode - the instrument observes the\n1.\nearth in the nadir position and the wavelength sampling is in the\ndiscrete mode (ie; a sequence of several pre-selected wavelengths\nfor determinations of total ozone and vertical ozone profiles).\n- 58 -","2.\nSun view mode - solar flux is measured after\nreflection off the diffuser for later use in determining the\nozone products and for obtaining data on the solar flux itself.\nThe wavelength sampling is both in the discrete mode and the\nsweep mode (ie. the total wavelength region of the instrument is\ncovered in a continous scan)\n3.\nWavelength calibration mode - the instrument is\ndirectly irradiated by an on-board mercury lamp to periodically\ncheck the instrument wavelength settings.\n4.\nDiffuser calibration mode - the instrument is\nagain irradiated by the mercury lamp but reflected of f the\ndiffuser. This allows for a continuing history of the relative\nspectral behavior of the diffuser.\nThe Preliminary Design Review was held in April 1981. No\nmajor flaws were un covered; however, it was noted that the\nphotomultiplier tube used as the detector exhibited an unexpected\nhysteresis effect. This is being evaluated by contractor and\ngovernment scientists.\nIII. EVALUATION OF THE GLOBAL TOVS TOTAL OZONE DATA\nEvaluation and validation of the TIROS-N data is continuing\nwith comparisons between the satellite-derived total ozone\namounts and those amounts determined by Dobson spectrophotometers\nlocated approximately below at the satellite Nadir at observation\ntime. Comparisons are being made also with the data determined\nby the R&D NASA SBUV instrument on the Nimbus 7 satellite.\nThe National Weather Service's Climate Analysis Center\ninitiated daily global total ozone analyses from the operational\nTOVS data in the spring of 1981, using the ozone values derived\nby NOAA's National Earth Satellite Service. The analyses are\npresently archived by the Climate Analysis Center and are being\ncompared against ground-based and NASA research satellite data\nfrom Nimbus 7. In addition, the data are being examined for\npossible utilization in the future by high-altitude aircraft to\navoid high in-cabin ozone concentrations detrimental to the\npassengers and crew.\n- 59 -","NATIONAL WEATHER SERVICE CLIMATE ANALYSIS CENTER\nCamp Springs, MD\nDuring 1980-1981 the Climate Analysis Center, Analysis and\nInformation Branch (AIB) has focused on two main areas: (1)\nimplementation of an operational stratospheric monitoring program\nand (2) examination of available data for trend analysis. The\nelements of each area are discussed below.\nI.\nOPERATIONAL STRATOSPHERIC MONITORING\n1.\nDaily, global meteorological analyses of height\nand temperature at 70, 50, 30, 10, 5, 2, 1 and 0.4 mb (20-55 km)\ncontinue to be constucted once/day, 1200 GMT. While the daily\nrecord exists back to late 1978, during the last two years\nseveral modifications have been initiated. For example the\noperational NESS retrievals up to 0.4 mb are utilized rather than\nderivations of temperatures from a simple regression scheme, as\npreviously done.\n2. Daily, global total ozone analyses from the\noperational TOVS data were initiated in the Spring of 1981 using\nthe ozone values derived by NESS. These analyses are presently\narchived by CAC and are being compared against ground-based and\nNASA research satellite data (Nimbus 7). In addition, the data\nare being examined for possible utilization by high-altitude\naircraft in order to avoid high ozone concentrations.\n3.\nA draft version of the Federal Plan for\nStratospheric Monitoring has been prepared, by personnel from\nNOAA, NASA, and FAA, with publication scheduled early in 1982.\nThis plan coordinates the monitoring elements of the several\nagencies into a cohesive effort to provide the data necessary for\nprecise trend evaluation.\n4.\nThe Climate Analysis Center has begun\nconsideration of the data flow and archiving of the complete\nstratospheric monitoring data base. The basic parameters will\ninclude data and synoptic analyses of:\n)meteorological fields - pressure height,\ntemperature and wind from 100 to 0.4 mb (16 to 55 km),\nb) total columnar ozone\nc) ozone mixing ratio from 30 to 0.4 mb (25 to 55\nkm) , the full range of the data available from the backscattered\nultraviolet technique employed on Nimbus 4 and 7 and planned for\nthe Tiros N operational SBUV-2 satellite series beginning in\nabout 1985.\n- 60 -","It is anticipated that all operational products will be\narchived at EDIS, Asheville, North Carolina and at NCAR, Boulder\nCO.\nII. EXAMINATION OF AVAILABLE OZONE DATA FOR TREND DETECTION\nMonthly average global synoptic analyses of total\n1.\nozone and ozone mixing ratio at 30, 10, 5, 2, and 1 mb for the\nperiod April 1970 - December 1976, from the Nimbus 4 BUV data,\nhave been accomplished. These analyses have been archived at the\nNational Space Science Data Center, Goddard Space Flight Center\nfor public dissemination on magnetic tape or microfilm. An atlas\nof the ozone charts is in preparation.\n2. The monthly average total ozone values from the\nabove Northern Hemisphere analyses have been examined for trends\nand a paper entitled, \"Total Ozone Variations 1970-74 Using\nBackscattered Ultraviolet (BUV) and Ground-based Observations\" is\nto be published in the Journal of Applied Meteorology.\nAfter consideration of the spatial gaps in the satellite\ndata (utilizing a technique suitable for the Northern Hemisphere)\nand comparison with concurrent Dobson ground-based observations,\nno significant trend was found in the Northern Hemisphere BUV\ndata over the years 1970-74.\n3. Monthly average ozone mixing ratio from the above\ndata, 30 to 0.4 mb, are currently being examined for trends, in\ncooperation with Professors George Tiao and Gregory Reinsel of\nthe University of Wisconsin (supported by the Chemical\nManufacturers Association), John Frederick of NASA Goddard Space\nFlight Center, John Deluisi of the Environmental Research\nLaboratory and Carl Mateer of the Atmospheric Environment\nService, Canada.\nThis multidisciplinary effort was established because there\nare significantly less upper level data available for comparison\nagainst the BUV satellite than is the case for total ozone and\nsignificant questions exist as to the effect of solar variations\nand stratospheric aerosols (e.g. from volcanoes) on the\nmeasurements themselves.\nUltimately, the ozone mixing ratio variations will be\ncompared with current theories on ozone depletion and the trend\ncompared with that recently described by Heath based on the\nlimited data samples from the BUV instruments on Nimbus 7 versus\nNimbus 4.\n4. Satellite ozone profile coverage extends from\nabout 30 to 0.4 mb (25-55 km) since the backscattered\n- 61 -","ultraviolet technique is currently bound at the lower level by\nour ability to consider single versus multiple scattering in the\nozone retrieval algorithm. As the ozone concentration maximum,\nhowever, is below 30 mb and as there is considerable concern\nregarding the possible impact of high altitude aircraft on the\nozone layer and also the health effect of ozone concentrations in\nthe aircraft cabins, the need exists for complete vertical ozone\nprofile information from the upper troposphere to the\nstratosphere.\nConsequently, a technique is being developed to derive ozone\nprofile information in the lower stratosphere and upper\ntroposphere utilizing the SBUV and possibly the TOVS\ninformation. This is, basically, a statistical regression method\nwhereby the average ozone amount in the lower stratosphere -\nupper troposphere is known from the difference between the total\nozone and that integrated from above 30 mb, and the vertical\nvariation within the region is determined via historical\nregression against available ozone balloon profiles. The\npreliminary results are very encouraging. We anticipate that a\nreport will be available by summer of 1982. One operational use\nof such data may be to provide guidance to the aviation industry\nto aid flight planning in order to avoid high ozone\nconcentrations.\n- 62 -","ENVIRONMENTAL DATA AND INFORMATION SERVICE\nI.\nARCHIVING TOVS SOUNDING DATA\nNOAA's National Environmental Satellite Service typically\nproduces 7,000 to 8,000 soundings per day from both NOAA-6 and\nNOAA-7 satellites. These soundings are derived from the three\nTIROS Operational Vertical Sounder (TOVS) sensors (Microwave\nSounding Unit, Stratospheric Sounding Unit, and High Resolution\nInfrared Radiation Sounder) and are archived on magnetic tape on\nwe ekly basis (7 days per tape) by the Satellite Data Services\na\nDivision of the Environmental Data and Information Service's\nNational Climatic Center. Each sounding contains layer me an\ntemperatures, precipitable water amounts, tropopause parameters,\ncloud cover, radiances, and total ozone amounts in Dobson\nunits. The TOVS sounding tapes are available from January 1,\n1979, and may be ordered from the National Climate Center.\n- 63 -"]}