{"Bibliographic":{"Title":"Program of research and monitoring for early detection of stratospheric ozone change : report to Congress of findings for 1982-1983","Authors":"","Publication date":"1984","Publisher":""},"Administrative":{"Date created":"08-16-2023","Language":"English","Rights":"CC 0","Size":"0000086210"},"Pages":["QC\n879.7\n.U5\n1982/\n1983\nProgram of Research\nDEPARTMENT\nOF\nCOMMUNITY\nand Monitoring for\n*\nEarly Detection of\nAvenue\nStratospheric Ozone Change\nSTATES OF\nReport to Congress of Findings for 1982-1983\nWashington, D.C.\nJanuary 1984\nU.S. DEPARTMENT OF COMMERCE\nNational Oceanic and Atmospheric Administration","QC\n879.7\nu5\n1982/83\nATMOSPHERIC\nProgram of Research\nAND\n\"and Monitoring for\nNOAA\nEarly Detection of\nStratospheric Ozone Change\nOF\nReport to Congress of Findings for 1982-1983\nWashington, D.C.\nJanuary 1984\nU.S. DEPARTMENT OF COMMERCE\nMalcolm Baldrige, Secretary\n,UnitedStates,\nNational Oceanic and Atmospheric Administration\nJohn V. Byrne, Administrator","","CONTENTS\nPage\nPREFACE\nV\nINTRODUCTION\n1\nSUMMARY OF FINDINGS\n3\nAERONOMY LABORATORY\n5\nI. Model Calculations\n5\nII.\nIn-Situ Stratospheric Composition Measurements\n6\nIII.\nLaboratory Kinetics Measurements\n6\nIV. Optical Measurements\n7\nV. Atmospheric Dynamics\n8\nVI. References\n8\nAIR RESOURCES LABORATORY\n11\nI. Ozone Monitoring\n11\nA.\nVariations in Ozone\n11\nTrend in Upper Stratospheric Umkehr Ozone Profile Data\n14\nB.\nC.\nDobson Spectrophotometer Ozone Monitoring\n14\n16\nII.\nStratospheric Temperature Monitoring\nIII.\nWater Vapor Monitoring\n18\nIV. Nitrous Oxide and Freon-11 and - 12 Monitoring\n18\nV. Ultraviolet Radiation Monitoring\n23\nVI. References\n23\nGEOPHYSICAL FLUID DYNAMICS LABORATORY\n24\nI. Three-Dimensional Modeling of Trace Constituent Behavior\n24\nAtmospheric N20 Experiments\n24\nA.\nReactive Nitrogen in the Troposphere\nB.\n25\nC. Examination of the Classical Theory for\nTropospheric Ozone\n26\nD.\nTropospheric Ozone Photochemistry\n27\nDevelopment of a Self-Consistent Two-Dimensional\nE.\nTransport Model\n27\niii","Page\nII. Modeling of the Troposphere - Stratosphere - Mesosphere\n27\nSystem\n28\nAnnual Mean Medium-Resolution Experiment\nA.\nAnalysis of Equatorial Waves in the SKYHI General\nB.\n28\nCirculation Model\nGeneration and Dispersion of Equatorial Disturbances\n29\nC.\n29\nSeasonal Cycle Medium-Resolution Experiment\nD.\n29\nE. Evaluation of Satellite Sampling of the Stratosphere\n30\nPhysical Processes in the Middle Atmosphere\nII.\n30\nRadiative Transfer\nA.\n30\nB.\nOzone Photochemistry\nSeasonal March of Radiative-Photochemical Temperature\n30\nC.\n31\nIV. References\nNATIONAL ENVIRONMENTAL SATELLITE, DATA, AND INFORMATION SERVICE\n33\n33\nI. TIROS Operational Vertical Sounder Total Ozone\nDevelopment and Implementation of Operational Solar\nII.\n34\nBackscatter Ultraviolet Instruments\n34\nIII. Reference\n35\nNATIONAL WEATHER SERVICE, CLIMATE ANALYSIS CENTER\nOperational Stratospheric Modeling\n35\nI.\n35\nII. Examination of Ozone Data for Trends\n37\nIII. References\niv","PREFACE\nSection 126 (on Ozone Protection) of P.L. 95-95, Clean Air Act Amendments\nof 1977, states that \"The Administrator of the National Oceanic and\nAtmospheric Administration shall establish a continuing program of research\nand monitoring of the stratosphere for the purpose of early detection and\nchanges in the stratosphere and climatic effects of such changes. Such\nAdministrator shall on or before January 1, 1978, and biennially thereafter,\ntransmit a report to the Administrator [of EPA] and the Congress on the\nfindings of such research and monitoring.\"\nAs part of its mission in Upper Atmospheric and Space Research, Global\nMonitoring of Climate Change, Basic Weather Analysis, and Environmental\nModeling, NOAA and its predecessors have conducted programs of research and\nmonitoring of the stratosphere for several decades. These programs were\nintensified and became significant components of the mandated program when\nnational concern developed about the possible effects of chlorofluorocarbons\nand other pollutants on stratospheric ozone.\nNOAA's stratospheric research and monitoring activities are conducted in\nsix centers: the Aeronomy Laboratory; the Air Resources Laboratory; the\nGeophysical Fluid Dynamics Laboratory; the Office of Research and Applications\nand the Satellite Data Services Division of the National Environmental\nSatellite, Data, and Information Service (NESDIS); and the Climate Analysis\nCenter of the National Weather Service.\nThe Aeronomy Laboratory conducts stratospheric composition measurements,\nlaboratory reaction kinetics measurements, model calculations, and atmospheric\ndynamics measurements.\nThe Air Resources Laboratory monitors stratospheric ozone, water vapor,\nand temperature variations, measures erythemal ultraviolet radiation at the\nground, and operates the U.S. portion of the World Meteorological\nOrganization Global Ozone Research and Monitoring Network.\nThe Geophysical Fluid Dynamics Laboratory conducts mathematical modeling\nof the dynamical, radiative, and chemical processes of the troposphere,\nstratosphere, and mesosphere, giving particular attention to the effects of\natmospheric and oceanic changes on global climate.\nThe NESDIS Office of Research and Applications develops and evaluates\nNOAA programs for operational satellite measurements of stratospheric\nproperties. The Satellite Data Services Division of the NESDIS National\nClimatic Data Center archives the data from the operational satellites, and\nprovides data to users and researchers upon request.\nThe Climate Analysis Center of the National Weather Service conducts\nanalysis of stratospheric meteorological and ozone data from both ground-based\nand satellite measurement systems, utilizing data provided by all\nparticipating United States agencies.\nV","Program of Research and Monitoring for\nEarly Detection of Stratospheric Ozone Change\n1982 - 1983\nINTRODUCTION\nThe problem of predicting stratospheric ozone concentrations involves\nalmost every aspect of atmospheric physics and chemistry. Ozone is formed\nprimarily by the energy of solar ultraviolet radiation dissociating molecular\noxygen, O2, into its component atoms in the high stratosphere, followed by\nrapid reactions of the 0 atoms with O2 to form ozone, 03. The ozone diffuses\ndown to the lower stratosphere under the influence of atmospheric turbulence,\nwaves, and wind fields. Ozone concentration is determined by a balance be-\ntween the classic source processes and various catalytic processes, involving\nprincipally the oxides of nitrogen, chlorine, and hydrogen (NO C10x, HO in\nwhich 0 and 03 are converted back to O2.\nThe chief importance of ozone relative to the surface environment is its\nability to absorb the potentially lethal ultraviolet radiation of the sun;\nthis same absorption provides the major source of heat for the stratosphere.\nDifferential heating in turn drives the wind systems of the stratosphere,\nwhich redistribute the ozone around the world and influence the tropospheric\nwind systems.\nFor many years, NOAA monitoring and research studies have been concerned\nwith virtually every aspect of this giant global cycle. Direct in situ sam-\npling and remote-sensing measurements are being made from balloons,\nsatellites, aircraft, and ground-based platforms, and the necessary instru-\nmentation developed within NOAA Laboratories. The data obtained are compared\nwith predictions of various atmospheric models. Laboratory chemical reaction\nrates and atmospheric transport parameters together with observational data,\nare then applied to develop and improve the models iteratively.\nThe National Oceanic and Atmospheric Administration and its predecessor\norganizations began systematic measurements of atmospheric ozone in the late\n1950's. Total ozone measurements were included in the regular work of the\nfour NOAA baseline stations, beginning in the early 1960's at Mauna Loa\n(Hawaii) and South Pole, and in the mid-1970's at Barrow (Alaska) and Tutuila\n(American Samoa). A network of stations for the specific purpose of\nmonitoring ozone was established in 1963 in Bismarck, N.D., Caribou, Maine,\nand Nashville, Tenn., to which was added Boulder, Colo., in 1967. (Three\nother stations were started which are no longer operated.) In addition, NOAA\nbegan in the early 1970's the coordination and processing of ozone\nmeasurements made by the National Aeronautics and Space Administration at\nWallops Island, Va., the Army at White Sands, N. Mex., Florida State\nUniversity at Tallahassee, Fla., and a cooperative station operated by the\nPeruvian Government at Huancayo, Peru.\nA realistic assessment of the long-term effects of chlorofluorocarbons\nand other anthropogenic emissions on stratospheric ozone has proved to be a\n1","considerably more elusive goal than was originally visualized. The principal\nreason for the prevailing uncertainty is the lack of precise knowledge of (1)\nthe reaction rates and products of some of the important chemical reactions\nand (2) the properties of several key \"reservoir\" species. The latest\ncalculations, made by NOAA and the National Center for Atmospheric Research in\ncollaboration, indicate that ozone depletion is likely to be a highly\nnonlinear function of added stratospheric chlorine. That is, the ozone\ndepletion may be small, or even slightly negative, for small chlorine\nincreases, but will increase dramatically once the chlorine exceeds a\n\"threshold\" range. If the calculations are correct, the prospect for early\ndetection of ozone trends is less encouraging than was thought originally.\n2","SUMMARY OF FINDINGS\nThe NOAA program of research and monitoring for stratospheric ozone\nchange involves remote and in situ sampling of ozone and other key trace\natmospheric species, stratospheric temperature, and stratospheric water vapor.\nThe data obtained are used to estimate global changes. Model calculations\nexplore the coupled radiative, chemical, and dynamic processes of the\natmosphere. Laboratory investigations, undertaken to specify rate reactions,\ncross sections, primary yields, product distributions, and temperature\ndependencies, lead to iterative model calculations.\nThe results of monitoring of ozone are summarized here. Full\ndescriptions of all the monitoring and research activities and their findings\nduring the 2-year period of this report are presented in the main sections of\nthis report, organized by Laboratory.\nVariations in Total Ozone\nTotal ozone data are being obtained and analyzed on a routine basis from\nthe World Meteorological Organization's Global Ozone Monitoring Network. The\nnetwork consists of ground-based instruments that compare the solar radiation\nin two adjacent wavelengths, in one of which ozone absorbs the ultraviolet\nradiation. These data are analyzed in terms of variation from the means of\nyear-average total ozone for each hemisphere and for the world, in each case\nover the period of record, 1958 through 1982. The analyses show little\nevidence of a long-term downward trend.\nVariations in Ozone Amounts in Different Layers of the Atmosphere\nObservations of changes in the intensity of solar radiation (in adjacent\nwavelengths) scattered from the zenith sky as the sun rises and sets (the\nUmkehr technique) from about 15 stations provide average ozone data for\nvarious layers in the atmosphere. Photochemical models predict that the\nlargest percentage decrease of ozone due to anthropogenic emissions will occur\nnear the 40 km level, with possible increases in ozone in the upper\ntroposphere and lower stratosphere.\nIn the 32-48 km layer of Umkehr measurements in the Northern Hemisphere\n(few Umkehr observation sites exist outside the Northern Hemisphere) there is\nevidence of a 2% - 3% decrease in ozone in this layer since 1970. (The\neffects of volcanic aerosols on the Umkehr technique, after large volcanic\neruptions, have been taken into account in this finding.)\nThe near invariance of total ozone together with the slight decrease in\nstratospheric ozone implies an increase in tropospheric ozone, and there is\nevidence from ozonesonde data that such an increase has occurred.\nAnalyses of the long-term (22 years) record of Umkehr vertical ozone\nprofile from the 13 highest quality observation sites indicates a\nstatistically significant relation between Umkehr measurement effects and\nstratospheric aerosols in the upper Umkehr layers, and further, a\n3","statistically significant negative trend of ozone in those layers after the\nUmkehr measurements have been corrected. The ozone changes detected by this\nanalysis are consistent with recent theoretical photochemical model\npredictions and represent the first directly observed, statistically\nsignificant evidence of a downward trend in stratospheric ozone. The amount\nfor Umkehr level 8 (38-43 km) is a change per year between 1970 and 1980 of\n-0.3%\n4","AERONOMY LABORATORY\nBoulder, Colorado\nI. Model Calculations\nThe Aeronomy Laboratory has continued its leadership in atmospheric\nchemical modeling, using both one-dimensional models that consider only ver-\ntical transport and two-dimensional models that also include the effects of\nmeridional transport. Collaboration with the Geophysical Fluid Dynamics\nLaboratory (GFDL) has also continued, with the objective of including chemical\neffects in a self-consistent way in the framework of the GFDL three-\ndimensional model, which represents the closest approach to the real atmos-\nphere and will ultimately lead to a fuller understanding of the influence of\nozone changes on global climate.\nThe problem of the origin of non-urban tropospheric ozone has also been\npursued, both through modeling and through ground-based measurements of ozone\nand its chemical precursors at a site in the Colorado Rockies, northwest of\nDenver. Tropospheric ozone contributes significantly to the total vertical\nozone column, so that its behavior needs to be understood and predicted if the\nfull environmental impact of ozone change is to be assessed. It now appears\nthat most tropospheric ozone has its origin in photochemical reactions within\nthe troposphere (Liu et al., 1980; 1983), rather than in direct intrusion from\nthe stratosphere. The chief precursor is NO originating in a variety of\nsources, including the upper troposphere (Noxon, 1981), lightning (Liu et al.,\n1983; Noxon, 1976), and urban pollution.\nA new two-dimensional model has been developed in collaboration with the\nNational Center for Atmospheric Research (Garcia and Solomon, 1983) and has\nbeen used in studies relating to the photochemistry and transport of strato-\nspheric ozone. In particular, the model has successfully explained the ob-\nserved global features of stratospheric NO2 for the first time (Solomon and\nGarcia, 1983), including the steep \"cliff\" between middle-latitude and polar-\nregion measurements.\nThe model has also been used to study the influence of the 11-year solar\ncycle on stratospheric composition, including the effects of variations in\nenergetic-particle precipitation and in solar radiation. The results suggest\nthat downward coupling from the thermosphere may increase stratospheric ozone\nat high latitudes.\nCollaboration with scientists from the University of Colorado has led to\nparticipation in the highly successful Solar Mesosphere Explorer satellite\nproject. The satellite, which was launched in October 1981, was instrumented\nto measure a wide variety of atmospheric constituents including ozone.\nSeveral solar-proton events occurred during the two years covered by this re-\nport, and the mesospheric ozone depletions caused by these events were clearly\ndetected by instruments on the satellite. Aeronomy Laboratory model predic-\ntions based on particle data provided by the Space Environment Laboratory\nshowed excellent agreement with the satellite observations (Solomon et al.,\n1983). Although these mesospheric ozone depletions have an insignificant\n5","effect on the total ozone column, they provide a unique opportunity to test\nour understanding of the basic photochemistry of ozone, so the agreement is\nvery encouraging.\nII. In-Situ Stratospheric Composition Measurements\nThe photochemistry of stratospheric ozone is exceedingly complex, and is\ncontrolled by a large number of minor atmospheric constituents. Water vapor\nand its chemical by-products have major parts in the complex chemical cycle\nthat leads to loss of stratospheric ozone. The odd-nitrogen (NO ) and odd-\nhydrogen (HO_, compounds are especially influential, and the Aeronomy\nLaboratory has for several years had a major program aimed at developing in-\nstrumentation to measure these constituents and their precursors and\ngathering data on a global basis using balloon and aircraft platforms.\nAn ultraviolet-photodissociation water-vapor instrument, developed by the\nAeronomy Laboratory (Kley et al., 1979), and flown on many occasions, has pro-\nvided information on stratospheric H2O concentrations with a precision and\nheight resolution never before achieved. Analysis of data from 11 flights\nover Panama on the NASA U-2 aircraft has been completed (Kley et al., 1982),\nand the results clearly show the vital role of tropical convective storms in\ninjecting water vapor into the stratosphere. Certain localized regions of the\ntropics probably have a major role because of the characteristic intensity of\ntheir convective activity. Chief among these is thought to be the western\nPacific, and Aeronomy Laboratory scientists are participating in planning an\ninternational experiment in that region. Data from the water vapor instrument\nhave also shown the existence of fine structure in the height profile of H20,\nwith corresponding fine structure in the ozone profile. The cause probably\nlies in changes in air trajectories with height rather than in photochemical\nchange. Further study is under way.\nAn instrument that measures the concentrations of NO and NO2 has been\nbuilt and successfully flown in collaboration with the National Center for\nAtmospheric Research. Four balloon flights have been made from Palestine,\nTex., and Gimli, Manitoba, and produced the first in situ measurements of NO2\nin the stratosphere. NO and NO2 play vital roles in the photochemistry of\nstratospheric ozone.\nA new instrument for in situ measurement of stratospheric ozone using a\ndual-beam ultraviolet absorption technique has been built and successfully\nflown. Flight data have revealed the fine structure in 03 profiles mentioned\nabove. The instrument participated in the NASA-sponsored balloon ozone\nintercomparison experiment in the summer of 1983.\nA triple-beam instrument is being developed that should be able to make\naccurate ozone measurements at the 40-km altitude where the maximum anthropo-\ngenic depletion is predicted.\nIII. Laboratory Kinetics Measurements\nFuture trends in stratospheric ozone concentrations are assessed through\nmodel calculations. The success of the models depends to a very high degree\non knowledge of the rates of the chemical reactions that take place in the\n6","stratosphere, and these chemical reaction rates can be determined only by\nlaboratory measurements. The Aeronomy Laboratory has for several years\nmaintained a laboratory kinetics program that has achieved a position of\ninternational leadership through measurement of several of the key reactions\nthat influence stratospheric ozone.\nThe principal technique used for neutral reaction studies is that of\nlaser magnetic resonance (LMR), first developed in the Boulder Laboratories of\nthe National Bureau of Standards. Ion-molecule reactions are studied with the\nflowing-afterglow and flow-drift techniques pioneered by Aeronomy Laboratory\nscientists.\nResults obtained within the 2-year period of this report include low-\npressure measurements of the reaction between HO2 radicals,\nHO2 + HO2 H2O2 + O2\nIn the atmosphere, the reaction is a source of hydrogen peroxide, H2O2, which\nplays an important role in stratospheric photochemistry. Work has also been\ncarried out on the chemistry of the gaseous chlorine species themselves (Lee\nand Howard, 1982; Lee et al., 1982), which cause ozone depletion, and on the\natmospheric chemistry of sodium, with the objective of determining the in-\nfluence of metallic species of meteoric origin on stratospheric ozone. A\nstudy of the chemistry of NO 3 an important intermediate species in the\nstratospheric nitrogen cycle, is also under way.\nIV. Optical Measurements\nThe use of optical (photometric and spectroscopic) remote sensing tech-\nniques for measuring atmospheric composition is an important part of the\nAeronomy Laboratory program. The basic technique for stratospheric applica-\ntions is very simple. It consists of measuring the intensity of sunlight or\nmoonlight in a spectral region containing a known absorption feature of a\nstratospheric constituent, and comparing the intensity with that in a neigh-\nboring spectral region outside the absorption feature. The difference gives a\nmeasure of the line-of-sight column density of the constituent. the technique\nwas first applied to NO2 and gave the first global measurements of the\nstratospheric NO2 column (Noxon, 1979, 1981; Noxon et al., 1979), delineating\nthe prominent \"cliff\"--sharp gradient--in the winter hemisphere measurements.\nThe same technique was applied to NO 3 (Noxon et al., 1978) and gave the\nfirst measurements of this transient species, which plays a key role in\nstratospheric photochemistry. The study yielded some results that were con-\ntrary to theory. The molecule appears to be attacked by some unknown\nscavenger in the troposphere, and the unraveling of the anomalous behavior\nshould yield fresh insight into the complexities of the atmospheric nitrogen\ncycle, with a direct bearing on the photochemistry of ozone.\nA similar technique has been applied to measurements of the vertical\ncolumn of the OH radical, and the long-term variation of the OH column. The\nresults have shown some unexpected features, including a highly significant\npositive correlation with the sunspot cycle (Burnett and Burnett, 1981, 1982).\nThe measurements and their analysis are continuing.\n7","Collaboration with a University of Colorado group led to the inclusion of\nan optical NO2 detector in the instrument payload of the Solar Mesosphere\nExplorer (SME) satellite, launched in October 1981. Analysis of data is now\nproceeding, and has revealed the possibility of studying global circulation\npatterns in the stratosphere by using NO2 as a tracer.\nThe El Chichon volcanic explosion of April 1982 gave rise to unexpected\nchanges in stratospheric composition, but unfortunately rendered the SME\ninstrument temporarily incapable of measuring NO2 The original ground-based\ntechniques, however, showed large decreases in NO2 associated with certain\nregions of the volcanic cloud. There were corresponding small increases in\nthe column abundance of stratospheric ozone, and changes in the stratospheric\nOH column. Analysis of these observations has begun.\nV. Atmospheric Dynamics\nThe problem of stratospheric ozone involves photochemistry, radiation,\nand dynamics. Ozone is formed photochemically mainly in the middle and upper\nstratosphere, and diffuses down into the lower stratosphere through the action\nof turbulence and wave motions. Its strong absorption coefficient for solar\nultraviolet radiation then provides the principal heat source that drives the\ngeneral circulation of the stratosphere.\nThe Aeronomy Laboratory has been investigating stratospheric dynamics for\nseveral years. The chief experimental tool has been the VHF Doppler radar\n(Gage and Balsley, 1978), which can measure horizontal and vertical motions\nover a wide range of heights. With the support of the National Science\nFoundation, the Laboratory constructed and is operating at Poker Flat, Alaska,\nthe world's largest radar dedicated to clear-air studies.\nThe Laboratory is making important contributions to knowledge of atmos-\npheric waves (VanZandt, 1982; Ecklund et al., 1981, 1982), turbulence,\n(Balsley and Carter, 1982; Larson et al., 1982) and circulation (Nastrom et\nal., 1982; Reid and Gage, 1981). Atmospheric motions on the scales of all of\nthese influence the transport of minor constituents in the stratosphere, and\nmust be included in the models used to assess trends in stratospheric ozone\nconcentrations\nVI. References\nBalsley, B. B., , and D. A. Carter, 1982. The spectrum of atmospheric velocity\nfluctuations at 8 km and 86 km. Geophys. Res. Lett., 9, 465.\nBurnett, C. R. and E. B. Burnett, 1981. Spectroscopic measurements of the\nvertical column abundance of hydroxyl (OH) in the earth's atmosphere.\nJ. Geophys Res., 86; 5185.\nBurnett, C. R., and E. B. Burnett, 1982. Vertical column abundance of\natmospheric OH at solar maximum from Fritz Peak, Colorado. Geophys.\nRes. Lett., 9, 708.\nCicerone, R. J., S. Walters, and S. C. Liu, 1983. Nonlinear response of\nstratospheric ozone column to chlorine injections. J. Geophys. Res., 88,\n3647.\n8","Ecklund, W. L., K. S. Gage, B. B. Balsley, R. G. Strauch, and J. L. Green,\n1982. Vertical wind variability observed by VHF radar in the lee of\nthe Colorado Rockies. Mon. Wea. Rev. , 110, 1451.\nEcklund, W. L., K. S. Gage, and A. C. Riddle, 1981. Gravity wave activity\nin vertical winds observed by the Poker Flat MST radar. Geophys Res.\nLett., 8, 285.\nGage, K. S., and B. B. Balsley, 1978. Doppler radar probing of the clear\natmosphere. Bull. Amer. Meteor. Soc., 59, 1074.\nGarcia, R. R., and S. Solomon, 1983. A numerical model of the zonally\naveraged dynamical and chemical structure of the middle atmosphere.\nJ. Geophys. Res., 88, 1379.\nKley, D. E. J. Stone, W. R. Henderson, J. W. Drummond, W. J. Harrop, A. L.\nSchmeltekopf, and T. L. Thompson, 1979. In-situ measurements of the\nmixing ratio of water vapor in the stratosphere. J. Atmos. Sci., 36,\n2513.\nKley, D., A. L. Schmeltekopf, K. Kelly, R. H. Winkler, T. L. Thompson, and\nM. McFarland, 1982. Transport of water vapor through the tropical\ntropopause. Geophys. Res. Lett., 9, 617.\nLarsen, M. F., M. C. Kelley, and K. S. Gage, 1982. Turbulence spectra in the\nupper troposphere and lower stratosphere at periods between 2 hours and\n40 days. J. Atmos. Sci., 39, 1035.\nLee, Y. P., and C. J. Howard, 1982. Temperature dependence of the rate\nconstant and the branching ratio for the reaction C1 + HO2 J. Chem.\nPhys., 77, 756.\nLee, Y. P., R. M. Stimpfle, R. A. Perry, J. A. Mucha, K. M. Evenson,\nD. A. Jennings, and C. J. Howard, 1982. Laser magnetic resonance\nspectroscopy of C10 and kinetic studies of the reactions of C10 with NO\nand NO2. Int. J. Chem. Kinet. , 14, 711.\nLiu, S. C., D. Kley, M. McFarland, J. D. Mahlman, and H. Levy, 1980. On the\norigin of tropospheric ozone. J. Geophys. Res., 85, 7546.\nLiu, S. C., M. McFarland, D. Kley, 0. Zafiriou, and B. Huebert, 1983.\nTropospheric NO and O3 budgets in the equatorial Pacific. J.\nGeophys. Res., 88, 1360.\nNastrom, G. D., B. B. Balsley, and D. A. Carter, 1982. Mean meridional\nwinds in the mid- and high-latitude summer mesosphere. Geophys. Res.\nLett., 9, 139.\nNoxon, J. F., 1976. Atmospheric nitrogen fixation by lightning. Geophys.\nRes. Lett., 3, 463.\nNoxon, J. F., 1979. Stratospheric NO2: II. Global behavior. J. Geophys.\nRes., 84, 5067.\n9","Noxon, J. F., 1981. NOX in the mid-Pacific troposphere. Geophys. Res. Lett.,\n8, 1223.\nNoxon, J. F., R. B. Norton, and W. R. Henderson, 1978. Observation of\natmospheric NO3. Geophys. Res. Lett., , 5, 675.\nNoxon, J. F., E. C. Whipple, and R. S. Hyde, 1979. Stratospheric NO2:\nI. Observational method and behavior at mid-latitude. J. Geophys. Res. ,\n84, 5047.\nReid, G. C. and K. S. Gage, 1981. On the annual variation in height of the\ntropical tropopause. J. Atmos. Sci., 38, 1928.\nSolomon, S. , and R. R. Garcia, 1983. Simulation of NO partitioning along\nisobaric parcel trajectories. J. Geophys. Res., , 88, 5497.\nSolomon, S., G. C. Reid, D. W. Rusch, and R. J. Thomas, 1983. Mesospheric\nozone depletion during the solar proton event of July 13, 1982. Part II.\nComparison between theory and measurements. Geophys. Res. Lett. 10,\n257.\nVan Zandt, T. E., 1982. A universal spectrum of buoyancy waves in the\natmosphere. Geophys. Res. Lett., 9, 575.\n10","AIR RESOURCES LABORATORY\nRockville, Maryland\nI. Ozone Monitoring\nResearch and development activities have so progressed over the past sev-\neral years that we now have a fairly well-defined strategy for monitoring trends\nin the total global ozone budget and trends in upper stratospheric ozone con-\ncentrations where the greatest percentages of depletions are expected to occur.\nMoreover, a global monitoring system composed of operational satellite in-\nstruments and ground-based instruments, having the necessary reliability for\nmaking the required long-term measurements, has been developed to maturity.\nAdvantages of the satellite system include global coverage with a single\ninstrument and real-time data acquisition. The ground-based Dobson ozone\nnetwork and the rocket and balloon ozonesonde networks continue to be needed\nfor verification and calibration of the satellite measurements.\nParts of the system are already in use, and the key satellite monitoring\ninstrument, the solar backscatter ultraviolet ozone monitor, will be deployed\non NOAA's TIROS-N by the end of 1984. Research teams of highly competent\nscientists from government, universities, and private industry have been\norganized at NASA and NOAA to oversee operations of the ozone-monitoring\nsystem and, with the new data products, verify past scientific findings and\nmake firmer assessments of future deleterious changes in the ozone layer.\nA. Variations in Ozone\n1. Variations in total ozone\nIt is important to monitor total ozone (the total amount of ozone in\na vertical column above a point on the earth's surface) because the variations\nin this quantity affect the amount of solar ultraviolet radiation reaching the\nground; an increase in ultraviolet radiation resulting from a decrease in\ntotal ozone could be deleterious to humans and plants. Total ozone data are\nbeing obtained on a routine basis from the World Meteorological Organization\nGlobal Ozone Monitoring Network (70 stations in the Northern Hemisphere and 20\nstations in the Southern Hemisphere). Ground-based instruments are used; they\ncompare the solar radiation in two adjacent wavelengths, in one of which ozone\nabsorbs the ultraviolet radiation.\nFigure 1 shows the variation in year-average total ozone for both\nhemispheres and for the world from 1958 through 1982, as estimated from the\nground station data (Angell and Korshover, 1983). There is more uncertainty\nin the Southern Hemisphere values (greater lengths of the vertical bars)\nbecause fewer stations are represented. The data show little evidence of\na long-term trend in total ozone in either hemisphere, or in the world as a\nwhole, although the 1982 Southern Hemisphere value is the second lowest of\n11","6\n4\nI\n2\nNorthern\n0\nHemisphere\n-2\n-4\n6\n4\n2\nSouthern\n0\nHemisphere\n-2\n-4\n4\n2\nWorld\n0\n-2\n-4\n-6\n1985\n1965\n1970\n1975\n1980\n1960\nFigure 1. Variation in year-average total ozone for the hemispheres and the\nworld, expressed as percentages of deviation from the mean. There is about\na 70% chance that the true value of the annual mean lies within the limits\nindicated by the vertical bars.\nrecord. Ozone amounts tended to be above average in 1958, 1968-70, and 1979,\nnear times of sunspot maxima, but it is too early to claim a relationship.\n2. Variations in ozone amounts in different layers of the atmosphere\nIt is important to monitor ozone variations in different layers of the\natmosphere because photochemical models predict that the largest percentage\ndecrease of ozone due to human activity will occur near the 40-km level, with\npossible increases in ozone in the troposphere and low stratosphere, up to a\nheight of about 20 km. That is, there could be a change in ozone profile,\nwith perhaps serious climatic effects, without a change in the quantity of\ntotal ozone.\nFigure 2 shows the variations in year-average ozone in north temperate\nlatitudes from 1961 through 1982, as estimated from Umkehr observations and\n12","12\n8\n4\n32-48 km\n0\nUmkehr\n-4\nFuego\n-8\nChichon\n8\nAgung\n4\n24-32 km\n0\nUmkehr\n-4\n4\n24-32 km\n0\nOzonesonde\n-4\n-8\n8\n4\n16-24 km\n0\nUmkehr\n-4\n8\n4\n16-24 km\n0\nOzonesonde\n-4\n-8\n12\n1960\n1965\n1970\n1975\n1980\n1985\nFigure 2. Variation in year-average ozone in stratospheric layers of north\ntemperate latitudes, from Umkehr and ozonesonde measurements.\nozonesonde measurements. Umkehr observations were made by about 15 stations\nin the ground network and involve observations of changes in the intensity of\nradiation (in adjacent wavelengths) scattered from the zenith sky as the sun\nrises and sets. (Results are presented only for the north temperate zone\nbecause most of the Umkehr observations are in this zone.)\nIt is apparent that in the 32-48 km layer the ozone amount estimated\nby the Umkehr method has been relatively low at or following the volcanic\n13","eruptions of Agung (Indonesia) in 1963, Fuego (Guatemala) in 1974, and E1\nChichon (Mexico) in 1982. These relatively low ozone values are believed to\nbe mostly fictitious, and due to the influence volcanic aerosols in the\nstratosphere have on the Umkehr observations. Determination of the ozone\ntrend in the 32-48 km layer is accordingly difficult when there are large\nvolcanic eruptions. Even so, there is evidence of a 2%-3% decrease in\nozone in this layer since 1970. It is not know at this time whether the\ncause of this indicated ozone decrease is natural or anthropogenic.\nUmkehr data for the 24-32 and 16-24 km layers suggest only about a 1%\ndecrease in ozone in these layers since 1970. However, ozonesonde (balloon-\nborne instruments making in situ measurements of ozone) data obtained from\nabout 15 stations for 1967-1982 suggest an ozone decrease of several percent\nin these layers. Thus, the available evidence suggests a small ozone\ndecrease since 1970 through most of the north temperate stratosphere. The\nnear invariance of total ozone (Fig. 1) together with the slight decrease in\nstratospheric ozone (Fig. 2) implies an increase in tropospheric ozone, and\nthere is evidence from ozonesonde data that such an increase has indeed\noccurred.\nB. Upper Stratospheric Umkehr Ozone Profile Data:\nEvidence of an Apparent Downward Trend\nA team of scientists from U.S. universities, the Canadian government,\nNASA, and NOAA investigated the heretofore neglected effect of stratospheric\ndust on long-term Umkehr observations of stratospheric ozone and found an\napparent downward trend in ozone concentration between 35 and 45 km. Reinsel\net al. (1984) analyzed the long-term (22 years) Umkehr vertical ozone profile\nrecord from 13 stations, together with the Mauna Loa atmospheric transmission\ndata, to examine the ozone record for stratospheric dust effects. Their\nanalysis indicates a statistically significant relation between Umkehr-\nmeasurement effects and stratospheric aerosols (originating from volcanic\ninjections) in the upper Umkehr layers (Table 1), and further, a statistically\nsignificant negative trend of ozone in those layers after the Umkehr\nmeasurements have been corrected. Although the cause or causes of the\nestimated trend cannot be unambiguously determined by statistical\ninvestigation, the ozone changes detected by the analysis are consistent with\nrecent theoretical photochemical model predictions (Weubbles et al., 1983),\nand represent the first directly observed evidence of a downward trend in\nstratospheric ozone. (See also National Weather Service, sec. II.)\nFor verification of the trend, it is essential that the Umkehr data be\nclosely monitored in the future to assess whether the detected trend persists.\nIt is equally important to improve the quality and quantity of Umkehr\nmeasurements and to obtain regular stratospheric aerosol measurements on a\nmore extensive geographic basis. This will allow for even more accurate\nadjustments for aerosol effects on the Umkehr data.\nC. Dobson Spectrophotometer Ozone Monitoring\nDuring 1982 and 1983, the Air Resources Laboratories continued to\nmonitor total ozone at ten of twelve Dobson instrument stations (Table 2).\n14","Table 1. Ozone change between 1970 and 1980, estimated from Umkehr vertical\nozone profiles corrected for the effects of atmospheric dust\n95% Confidence\nChange\nUmkehr\nInterval\nPer Year\nLayer\n(%)\n(altitude)\n9\n+0.39\n(43-48 km)\n-0.29\n8\n-0.30*\n+0.16\n(38-43 km)\n7\n+0.17\n(34-38 km)\n-0.22\n6\n+0.11\n(29-34 km)\n-0.00\n5\n+0.14\n-0.04\n(24-29 km)\n*This is consistent with the Weubbles et al. (1983) updated\ntheoretical predictions of ozone depletion rate.\nTable 2. 1983 U.S. Dobson ozone spectrophotometer station network\nInstrument\nPeriod of Record\nNumber\nAgency\nStation\nNOAA\n1 Jan. 63-present\n33\nBismarck, N. Dak.\n34\nNOAA\n1 Jan. 63-present\nCaribou, Maine\n42\nNOAA\n19 Dec. 75-present\nTutuila Is. , Samoa\nNOAA\n2 Jan. 64-present\n63\nMauna Loa, Hawaii\nNOAA/NASA\n1 Jul. 67-present\n38\nWallops Is., , Va.\nNOAA\n2 Aug. 73-8 Oct. 82\n76\nBarrow, Alaska\nNOAA\n1 Jan. 63-present\n79\nNashville, Tenn.\nNOAA\n1 Sep. 66-present\n82\nBoulder, Colo.\n5 Jan. 72-29 Jan. 82\n86\nNOAA/Army\nWhite Sands, N.Mex.\nNOAA/Florida\n2 Jun. 73-31 May 79\n58\nTallahassee, Fla.\nState U.\n5 Oct. 81-present\nNOAA/Huancayo Obs.\n14 Feb. 64-present\n87\nHuancayo, Peru\n80\nNOAA\n5 Dec. 63-present\nAmundsen-Scott,\nAntarctica\n15","Observations at Pt. Barrow, Alaska were discontinued in October 1982 in\nanticipation of relocating that station to Poker Flat, Alaska. Observations\nat White Sands, N. Mex., were terminated in January 1982 when the U.S.\nDepartment of the Army could no longer support the program.\nFunding was obtained in 1982 from the U.S. Environmental Protection\nAgency, the Chemical Manufacturers Association, the WMO Voluntary Coopera-\ntion Program, and NOAA for automating six Dobson spectrophotometers and\nestablishing them in a global network for long-term Umkehr measurements of\npossible ozone changes at 40 km altitude due to the effects of anthropogenic\npollutants. As of 31 December 1983, five of the instruments, as well as\nAsh-Dome shelters for the instruments, had been automated. Five of the\ninstruments were installed and are operational at Haute Provence, France;\nPoker Flat, Alaska; Mauna Loa, Hawaii; Perth, Australia; and Boulder Colo.\nThe remaining two instruments are awaiting host-nation clearances for\nHuancayo, Peru, and Pretoria, South Africa. The automated Dobson instrument\nat Boulder has been operational since early in 1983.\nFollowing the eruption of El Chichon volcano in April 1982, a program was\nimplemented at Mauna Loa Observatory to study the effects of stratospheric\naerosols on Umkehr observations. Initial measurements confirmed previous\nobservations and theoretical work indicating that the accuracy of ozone\nmeasurements near 45-km altitudes would be adversely affected. When the\nstratosphere was heavily loaded with aerosols in May 1982, conventional Umkehr\nmeasurements yielded erroneous negative ozone values near 45 km. As the\naerosol layer became progressively thinner, the Umkehr measurements reverted\nto near-normal values by the end of 1982.\nIn 1981, seven standard lamp units were built and calibrated in the\nLaboratory. These were sent to the seven WMO regions of the globe for\nchecking Dobson instrument calibrations at 5 to 19 stations in each region.\nResults from the majority (77) of the stations have been received, and show\nthat 36% of the instruments require recalibration.\nII. Stratospheric Temperature Monitoring\nStratospheric temperature changes affect the rates of photochemical\nchanges that are relevant to the ozone balance. Monitoring of stratospheric\ntemperature is also important because of the cooling of the stratosphere\nassociated with an increase in carbon dioxide (CO2). Since the CO2-induced\nstratospheric cooling should be considerably greater than the CO2-induced\ntropospheric warming, it is the stratosphere that should provide the earliest\nwarning of a CO2 effect.\nIn the Northern Hemisphere, stratospheric temperatures are being\nmonitored from both rocketsonde and radiosonde data. Figure 3 shows\nvariations in year-average temperature, as estimated from rocketsonde or\nradiosonde data (Angell and Korshover, 1983, a,b).\n16","6\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\nRocketsonde\n-1\n-2\n2\n1\n26-35 km\n0\nRocketsonde\n1\n-2\n1\nT\n16-24 km\n0\nRadiosonde\n1\n-2\nChichon\nAgung\n-3\n1960\n1965\n1970\n1975\n1980\n1985\nFigure 3. Variation in year-average temperature in stratospheric layers of\nthe Northern Hemisphere. Temperatures for 46-55, 36-45, and 26-35 km\nlayers were estimated from rocketsonde data through 1982, obtained\nmostly in the western quadrant of the Northern Hemisphere. Temperatures\nfor the 16-24 km layers were estimated from radiosonde observations\nthrough 1982, throughout the Northern Hemisphere. The vertical bars\nrepresent 70% confidence limits. That is, there is about a 70% chance that\nthe true value of the yearly mean temperature lies between the top and\nbottom limits. Arrows labeled SS MAX indicate years of maximum sunspot\nactivity.\n17","The radiosonde data for the 16-24 km layer show that there was a warming\nof the low stratosphere following the volcanic eruptions of Agung (Indonesia)\nin 1963 and El Chichon (Mexico) in 1982, but there is little evidence of a\nlong-term trend in temperature in this layer. The rocketsonde data, however,\nsuggest a large temperature decrease between 1970 and 1976 but little\ntemperature change thereafter. The indicated cooling between 1970 and 1976 is\nmuch too large to be associated, in its entirety, with a CO2 effect, and the\nreason for this large decrease is unknown. There is evidence from the\nrocketsonde data of relative temperature maxima near the times of sunspot\nmaxima in 1969 and 1979, but it is too early to claim a relationship.\nIII. Water Vapor Monitoring\nThe radiative and photochemical properties of water vapor in the strato-\nsphere and the role of water vapor as a tracer of exchange between the tropo-\nsphere and the stratosphere are the subject of continued research. Regular\nsoundings from Boulder are combined with earlier data from Washington, D.C.,\nto support studies of stratospheric water vapor distribution and variations.\n(See also Aeronomy Laboratory, sec. II)\nBelow 15 km (120 mb) in the upper troposphere and lower stratosphere,\nseasonal fluctuations in the tropopause produce a marked annual variation\nin water vapor mass mixing ratio. Around 20 km (50 mb) altitude, the seasonal\nvariations are small, rendering this region advantageous for studying\nvariations on longer time scales. A curve fitted to the individual\nmeasurements provides evidence of a prominent quasi-biennial oscillation\n(QBO). This QBO suggests a modulation of the poleward transport of Hadley\nCell circulation by tropical stratosphere zonal winds. A quadratic trend\nline fitted to the water vapor data at 20 km shows that the earlier upward\ntrend through the 1960's became negative during the late 1970's, so that\ncurrent values approximate those observed in the early 1960's.\nIV. Monitoring of Freon-11 and -12, and Nitrous Oxide\nFreon-11(CC13F) and Freon-12 (CC12F2), both anthropogenic, are decom-\nposed in the stratosphere by photolysis, causing catalytic destruction of\nstratospheric ozone by released chlorine atoms. Nitrous oxide (N20) also en-\nters into stratospheric photochemical reactions (involving NO ) as a\nsignificant precursor to the catalytic destruction of ozone. Nitrous oxide\nis\nemitted from land by bacte- rial denitrification of fixed nitrogen, as well as\nfrom combustion of fossil fuels.\nThe Air Resources Laboratory has been monitoring F-11, F-12, and N20\nsince 1977. Data obtained at Pt. Barrow, Alaska; Niwot Ridge, Colorado; Mauna\nLoa, Hawaii; American Samoa, South Pacific; and South Pole, Antarctica, are\nshown in Figures 4-6. Results of linear regression trend analyses of the\nmeasurement data are shown in Tables 3 and 4.\n18","BRW\nNWR\nMLO\nSMO\nSPO\n80\n79\n81\n78\n82\n77\nFigure 4. Freon-11 data obtained at the Air Resources Laboratory baseline\nobservatories. (Outlying points have been removed.)\n19","BRW\nNWR\nMLO\nSMO\nSPO\n80\n81\n79\n82\n78\n77\nFigure 5. Freon-12 data obtained at the Air Resources Laboratory baseline\nobservatories. (Outlying points have been removed.)\n20","BRW\nNWR\nMLO\nSMO\nSPO\n80\n79\n81\n82\n78\n77\nFigure 6. Nitrous oxide data obtained at the Air Resources Laboratory\nbaseline observatories. (Outlying points have been removed.)\n21","Table 3. Summary of CCl3F (Freon-11) and\nCCl2F2 (Freon-12) measurement results\n1977-1982\n1 Jan 1977\n1982 Mean\nGrowth Rate\nMixing Ratio\nMixing Ratio\n(pptv)*\n(pptv\n(pptv)\nStation\nCC13F\n154.1+0.40\n11.12+0.11\n214.9\nBarrow\n10.93+0.12\n150.1+0.43\nNiwot Ridge\n210.5\n145.3+0.41\n11.32+0.11\n206.3\nMauna Loa\n12.10.0.11\n134.740.37\n202.2\nSamoa\n134.6+1.96\n12.70.0.57\n214.9\nSouth Pole\nCC12F2\n16.73.0.26\n270.0+0.97\n362.9\nBarrow\n14.15+0.32\n276.7#1.23\n356.8\nNiwot Ridge\n15.67+0.28\n268.5#1.03\n358.8\nMauna Loa\n241.8+0.76\n18.39.0.22\n345.8\nSamoa\n22.34+0.74\n225.7+2.67\n364.5\nSouth Pole\n*Indicated uncertainties are 95% confidence internal standard errors.\nTable 4. Summary of N2O measurement results\n1977-1982\n1 Jan 1977\n1982 Mean\nGrowth Rate\nMixing Ratio\nMixing Ratio\n(ppbv\n(ppbv)*\n(ppbv)\nStation\n0.6140.05\n300.140.20\n303.8\nBarrow\n0.99+0.06\n299.120.23\n304.8\nNiwot Ridge\n0.99+0.07\n298.340.25\n304.0\nMauna Loa\n1.59+0.09\n299.140.31\n309.3\nSamoa\n0.01+0.09\n297.5#0.32\n302.2\nSouth Pole\n*Indicated uncertainties are 95% confidence internal standard errors.\n22","V. Ultraviolet Radiation Monitoring\nUltraviolet radiation has been monitored since 1974 by the worldwide\nnetwork of Robertson-Berger (RB) meter sites. During the 1982-83 period,\n32 instruments were in operation, 18 of which were located in the contiguous\nUnited States. Nine of the U.S. group have continuous 10-year records, and\nnine have been in operation 3 to 5 years. The non-U. - S. stations have\nperiods ranging from 1 to 9 years. The network was originally established\nin response to perceived threats to the ultraviolet-absorbing stratospheric\nozone layer through the introduction of certain anthropogenic chemicals into\nthe environment. Any subsequent increase of ultraviolet radiation is anti-\ncipated to induce increasingly harmful biological effects such as higher human\nskin cancer rates.\nThe RB meters are operated continuously. They provide half-hourly\nintegrals of UV radiation, which are recorded in arbitrary rather than\nabsolute energy units. The instrument has proved to be stable and very rugged\nin operation, yielding data recovery rates in excess of 90% at nearly every\nsite. Further, 13 of the U.S. locations are National Weather Service\nstations, which provide concomitant meteorological observations.\nAdditionally, two stations, Bismarck and Tallahassee, also have daily total\nozone measurements available for comparison purposes. In 1983, an Air\nResources Laboratory scientist compared the RB meter with a double slit\nmonochromator, establishing a method by which the RB unit of measurement may\nbe converted to energy units.\nVI. References\nAngell, J. K., , and J. Korshover, 1983a. Global temperature variations in\nthe troposphere and stratosphere, 1958-1982. Mon. Wea. Rev. , 111,\n901-921.\nAngell, J. K. , and J. Korshover, 1983b. Global variation in total ozone\nand layer-mean ozone: An update through 1981. J. Climate and Appl.\nMeteor. , 11, 1611-1627.\nReinsel, G. C. , G. C. Tiao, J. J. DeLuisi, C. L. Mateer, A. J. Miller,\nJ. E. Frederick, 1984. Analysis of upper stratospheric Umkehr ozone\nprofile data for trends and the effects of stratospheric aeorosols.\nJ. Geophys. Res., , 89, 4833-4840.\nWeubbles, D. J., 1983. A theoretical analysis of the past variations in\nglobal atmospheric composition and temperature structure. Lawrence\nLivermore Laboratory Report UCRL-53423, 161 pp.\n23","GEOPHYSICAL FLUID DYNAMICS LABORATORY\nPrinceton, New Jersey\nChanges in atmospheric trace constituents and the climatic effect of such\nchanges cannot be adequately predicted or understood without a firm knowledge\nof the processes that maintain or alter the normal state. Research to improve\nsimulation and understanding of the atmosphere (including the stratosphere)\nhas been under way at the Geophysical Fluid Dynamics Laboratory (GFDL) for\nmore than 25 years. The middle atmosphere research effort was accelerated in\n1970 when a commitment was made to investigate the chemistry, radiation, and\ndynamics of the stratosphere. Stratospheric research performed at GFDL since\nJanuary 1982 builds on the considerable research base established earlier.\nI. Three-Dimensional Modeling of Trace\nConstituent Behavior\nSince 1979, GFDL has explored problems relating to transport and chemistry\nof trace constituents, using one of the GFDL global three-dimensional (3-D)\ngeneral circulation models (GCM) (e.g., Manabe et al., 1974; Manabe and\nMahlman, 1976). This model provides self-consistent, time-dependent winds as\ninput to a separate model to study many aspects of trace constituent transport\nand chemistry (for model details, see Mahlman and Moxim, 1978; Levy et al.,\n1982).\nA. Atmospheric N2O Experiments\nNitrous oxide (N20) is well recognized to be the most important\nprecursor gas controlling the ozone amount in the atmosphere. This gas has\nmainly biological sources at the earth's surface, is essentially inert in\nthe troposphere and lower stratosphere, and is destroyed photochemically in\nthe middle stratosphere. A small but important part of that photochemical\ndestruction leads to the formation of \"reactive nitrogen\" in the form of\nnitric oxide (NO). This gas and its photochemical companion, NO2, form the\nmajor catalytic ozone destruction cycle in the lower and middle stratosphere.\nThus, a firm quantitative understanding of N20 is essential for a thorough\nunderstanding of ozone and its change.\nAnalysis has been completed on a number of 3-D model experiments\nexploring the structure and variability of N20 from various surface sources.\nIn addition to the previously reported results, predictions are offered on\nthe real behavior of tropospheric N20, which await observational testing: (1)\na significant (~1%) excess of N20 in the Southern Hemisphere middle\ntroposphere (assuming no significant anthropogenic sources); (2) magnitudes of\nspatial and temporal variability of N20 in and away from the boundary layer;\nand (3) conditions under which the empirical \"Junge rule\" should be\ninapplicable (Levy et al., 1982).\nWork has also been completed on a series of experiments designed to\ntest various photodestruction hypotheses. The results strongly suggest that\nmore photochemical destruction of N20 is required than the model allows\n24","through use of current absorption cross section data. (Recent measurement\nwork [Frederick and Mentall, 1982] showing reduced O2 cross sections indicates\nthat a portion of the difference may be identified.) Especially useful is the\nfinding that properly calculated global-average 1-D eddy diffusion\ncoefficients should be applicable to a wide range of long-lived trace gases.\nThe analysis also predicts that all horizontal maps of the vertical \"topo-\ngraphy\" of time-mean mixing ratio surfaces will be essentially the same for a\nrather wide class of long-lived trace constituents.\nThis relationship is predicted to hold as long as the stratospheric\nchemical destruction time scale is long compared with an appropriate meridional\ntransport time scale. It has allowed development of a simple theory that\npredicts the temporal tracer variability in terms of time-mean spatial\ngradients and non-conservative effects (Mahlman et al., 1984). These two\npredictions will be tested against available observational data.\nB. Reactive Nitrogen in the Troposphere\nIn recent years it has been recognized that understanding of tropospheric\nozone requires a quantitative understanding of the tropospheric budget of\nreactive nitrogen (e.g., Liu et al., 1980; Kley et al., 1981). However,\nsources of tropospheric reactive nitrogen include stratospheric injection\n(Levy et al., 1980), surface combustion, and possibly lightning and surface\nbiological activity.\nGFDL has completed a set of 3-D model experiments designed to investigate\nthe possible effect of the U.S. combustion source on the global tropospheric\nbudget of reactive nitrogen. In all experiments the combustion nitrogen is\nassumed to be immediately converted to HNO3, which is rapidly removed by\nboth precipitation and contact at the earth's surface. This assumption\nshould produce a lower-limit estimate of the contribution of combustion\nnitrogen to the global distribution of reactive nitrogen.\nA series of 2-month integrations showed that even very rapid rainout (a\nglobal lifetime of ~2 days in the lower troposphere) is not sufficient to\nproduce an HNO3 profile in the upper troposphere that drops off with altitude\nas fast as or faster than that of H20, another very efficiently removed\ntrace gas. Adding another mechanism, the selective filtering of water\nsoluble trace gases in rising air, produced a more appropriate HNO profile.\nHowever, the fundamental uncertainty in quantifying the removal processes\nremains a very significant barrier to complete understanding of reactive\nnitrogen, and thus, of ozone.\nThe experiment that included filtering of rising air, as well as wet\nand dry removal, has been integrated from January through August. The model\nindicates that there is no significant transport into the Southern Hemisphere,\nand stratospheric injection dominates down to 500 mb almost everywhere. How-\never, there is significant transport of U.S. HNO 3 to Canada and Latin America,\nand episodic events carry it over the North Atlantic to Europe, up to the\nArctic, and out over the eastern equatorial Pacific. Extratropical cyclones\nare the major mechanism for lifting combustion HNO3 out of the boundary layer\nto the middle and upper troposphere where long-range transport can take over.\n25","It is also found that the effective source to the atmosphere is sig-\nnificantly less than the surface emission rate for a substance such as HNO\nthat is easily removed by surface destruction. The amount depends on both the\nemission height and the intensity of boundary layer mixing processes.\nWork is continuing on quantifying removal. More carefully posed model\nexperiments are being planned for multiple subspecies of the reactive nitrogen\ngroup, particularly interactive NO (NO+NO2) and HNO.\nC. Examination of the Classical Theory for Tropospheric Ozone\nIn polluted boundary layer air, ozone is clearly under strong photo-\nchemical influence; however, ozone in the \"unpolluted\" troposphere may or may\nnot be, depending on the amount of reactive nitrogen present (see sec. I.B).\nThe 3-D GFDL global tracer model has been used to explore one possibility:\nTropospheric ozone might be explained by the \"classical\" mechanism (i.e.,\ntransport of ozone from the stratosphere, balanced by contact removal at the\nsurface). This would be reasonable, simply because the classical processes\nmust be present, even if an active tropospheric ozone chemistry is also\ninvolved.\nThe calculations use the stratospheric ozone chemistry described by\nMahlman et al. (1980). The uncertainty in modeling surface removal rates is\naddressed by performing two separate numerical experiments, using \"upper\nlimit\" and \"lower limit\" removal efficiencies.\nOutside the continental boundary layer, the results of the calculations\nusing upper- and lower-limit surface removal rates bracket the observed\ndata. The model's interhemispheric and meridional gradients agree well with\nobservations, except for the northern high latitudes, where the model shows\na much stronger gradient than is suggested by the few observations available.\nA detailed analysis of model-generated local vertical ozone profiles and\ncomparison with available observations show good qualitative agreement in\nboth profile means and variances. In general, the model seasonal variations\nalso show reasonable agreement with observations. An exception in Northern\nHemisphere middle latitudes might be explained by a model transport defi-\nciency.\nThe results are much less certain in the boundary layer, particularly\nover land. Over land, the model surface ozone values show too steep a\nvertical gradient, too high a variability, and no summer maximum. These\ndeficiencies may be the result of excluding photochemistry, but they may\nalso be due to too strong mixing in the bottom layer of the model, too weak\nmixing in the boundary layer as a whole, or no seasonal structure in the\nmodel surface removal efficiencies (Levy et al., 1984).\nMeasurement and modeling studies are needed to resolve discrepancies.\nThe study has clearly demonstrated, however, that classical mechanisms are\nessential in any complete model of tropospheric ozone.\n26","D. Tropospheric Ozone Photochemistry\nThe studies discussed have indicated that a detailed understanding of\nozone photochemistry (in the presence of atmospheric transport) is essential.\nTherefore, a detailed ozone photochemical model has been developed. To test\nsome of the previous concepts, model results, and observations, experiments\nwith a detailed diurnal ozone photochemical model have been carried out at\n500 mb for summer and winter conditions at 15° and 45° latitude (ozone, and\ncarbon monoxide and water vapor mixing ratios are specified; methane chemistry\nis neglected; NO mixing ratios are varied systematically from 10 pptv to 1\nX\nppbv).\nThe results, combined with those of the classical ozone study (sec.\nI.C), suggest that net photochemical destruction of ozone may take place in\nsummer high latitudes, while some net production may occur in summer middle\nlatitudes. These conclusions are critically dependent upon highly uncertain\nassumptions about the amount of NO present in the atmosphere (see sec.\nX\nI.B.).\nE. Development of a Self-Consistent Two-Dimensional\nTransport Model\nSeveral atmospheric chemistry and transport problems have been profitably\nattacked through use of economical zonally averaged 2-D transport models.\nYet it has been recognized for some time (e.g., Mahlman, 1975; Plumb, 1979)\nthat the usual 2-D models are formulated in a manner consistent with con-\ntemporary understanding of atmospheric dynamics.\nTo see if fundamental improvements can be made, statistics from the 3-D\ntracer transport model are being used to evaluate the scientific feasibility\nof a self-consistent 2-D transport model. In principle, two well-posed 3-D\ntracer experiments provide all the transport coefficients and advective\nvelocities required to satisfy the constraints of recent \"generalized diffusion\ntensor\" theories (Matsuno, 1980; Danielsen, 1981). Work on this problem is\nin the preliminary stage.\nII. Modeling of the Troposphere-Stratosphere-\nMesosphere System\nFor the past 8 years, GFDL has been developing a comprehensive, 3-D\ngeneral circulation model of the radiative-chemical-dynamical structure of the\natmosphere from the earth's surface to the mesopause (e.g., Fels et al.,\n1980). (This model is hereafter referred to as SKYHI. ) A major goal has been\nto develop an internally consistent capability for simulating ozone amount and\nits changes. This involves a careful and accurate coupling of the chemistry\nwith a self-consistent realistic transport and radiative transfer. As the\nmodel capability evolves, progressively more realistic experiments will be\nconducted. Recent experiments with SKYHI have been designed (and new\ntechniques have been developed) to evaluate model performance in various\naspects of circulation and transport dynamics.\n27","A. Annual Mean, Medium-Resolution Experiment\nThis SKYHI experiment uses annual mean solar radiation (no seasonal\ncycle) and medium resolution (40 levels in the vertical and a 5° latitude\nhorizontal grid) to evaluate aspects of the model's dynamics and associated\ntransport. The analysis, using newly developed \"Eliassen-Palm\" diagnostics,\nshows that wave disturbances reduce the mean speed of the westerlies. The\neffect is particularly large in the upper mesosphere where the wave-induced\nzonal flow decelerative forces are large enough to \"close off\" the polar\nnight jet at about 65 km. Another dramatic result is the effect of dis-\nturbances on the middle-latitude tropospheric westerlies: the mean tropo-\nspheric westerly wind shear is reduced by about 2 m S 1 km 1 day ¹\nThe analysis also indicates wave-induced acceleration of westerly winds\nat heights of about 28 and 60 km over the equator, associated with\nlocal westerly wind maxima. A separate analysis has shown that the required\nmomentum deposition at 28 km is accomplished by \"traditional\" equatorial\nKelvin waves. On the other hand, at 60 km the momentum is mainly due to\n\"fast\" Kelvin waves with eastward phase speeds of about 80 m s ¹\nFor middle latitudes, the conclusion of the new diagnostics about the\nforce exerted by eddies on the zonal flow is qualitatively opposite to that\nprovided by traditional methods. The new diagnostic conclusion was tested\nthrough a companion model experiment in which all eddy quantities were virtu-\nally removed from the stratosphere. The new diagnostics provided a far better\nprediction of the subsequent change in mean flow than do the traditional ap-\nproaches (Andrews et al., 1983). The new diagnostics also give improved in-\nsights into mechanisms responsible for transport of ozone and other trace con-\nstituents. Such approaches have already stimulated new developments of SKYHI,\nwhich have yielded improved quantitative modeling of stratospheric transport.\nB. Analysis of Equatorial Waves in SKIHI\nA space-time spectral analysis of equatorial middle-atmosphere Kelvin\nand gravity waves, as simulated by the SKYHI annual mean insolation model\n(sec. II.A), produced some remarkable findings related to stratospheric\ndynamics and associated transport.\nThe model Kelvin waves are associated with zonal wavenumbers 1-2, have\nan eastward phase velocity, and tilt eastward with height. The lower-\nstratosphere \"traditional\" Kelvin wave has periods of 10 to 30 days and a\nvertical wavelength of 10 km, in agreement with many observational results.\nThe upper stratospheric Kelvin waves (periods of 5 to 7 days and a vertical\nwavelength of 20 km) are as observed a few years ago by Hirota (1979). The\nmesospheric Kelvin waves have periods of 3 to 4 days and a vertical wave-\nlength of about 40 km. These correspond closely to the wave discovered very\nrecently by Salby et al. (1984). All these Kelvin waves transport eastward\nmomentum upward.\nSKYHI gravity waves of zonal wavenumbers 1-15 and periods ~0.5 to\n2 days long are prevalent in the equatorial mesosphere. Their eastward- and\nwestward-moving components transport eastward and westward momentum upward\nand contribute to the mesospheric zonal momentum balance as much as or even\nmore than do Kelvin waves.\n28","C. Generation and Dispersion of Equatorial Disturbances\nA series of calculations has been undertaken to understand the mechanism\nproducing the middle-atmosphere tropical disturbances observed by satellite\nand in SKYHI (sec. II.B). In particular, transient responses to localized,\nimpulsive tropical latent heat releases are being investigated by an initial-\nvalue approach, which includes the effects of wave absorption and refraction.\nThe results show the presence of a \"spectrum\" of equatorially trapped,\nvertically propagating Kelvin and gravity waves centered about a vertical\nwavelength twice the depth of the imposed heating. Selective absorption of\nthe slower, shorter vertical wavelength components of the wave spectrum\nappears to be responsible for the predominance of higher frequency distur-\nbances at upper levels in the SKYHI simulations and in observations (Hirota,\n1979; Salby et al., 1984).\nThe second result corresponds to a spectrum of normal modes with an\nequivalent barotropic character. These waves are vertically trapped, but\nthey disperse energy toward higher latitudes. Accordingly, they may prove to\nbe important in the dynamics of the middle-latitude troposphere as well.\nD. Seasonal Cycle Medium.Resolution Experiment\nThe medium-resolution SKYHI general circulation model described in sec.\nII.A has been run for a couple of years with an annual cycle of solar\nradiation. The analysis includes a comparison of the simulation against\nobservations (Mahlman and Umscheid, 1984). Successful simulations include the\ncold equatorial tropopause, the middle-latitude warm belts of the winter lower\nstratosphere, clear separation between the subtropical and polar night jet\nstreams, reversed meridional temperature gradients in the winter mesosphere\n(and closed-off polar night jet), stratospheric summer easterlies of the\nproper magnitude and depth, a strong sudden warming in the model lower\nmesosphere, and a pronounced equatorial semi-annual oscillation.\nThe model's sudden warming event exhibits many features of observed\nwarmings that do not penetrate downward into the middle stratosphere. In\nthe lower mesosphere, the polar cap warms by more than 43° in 15 days. The\nhigher temperatures increase the polar cap diabatic cooling rates to more than\n15°C day Accompanying the warming is a deceleration of the mesospheric jet\nby more than 80 m S 1. This sudden warming was initiated by a large increase\nin the vertical component of Eliassen-Palm flux emanating from the troposphere\n(Andrews and McIntyre, 1976). That flux leads to flux divergences exceeding\n-40 m S -1 day -1 just above the stratopause. Such a level of model forcing is\nsufficient to induce the large deceleration (and its associated warming). The\nprocess appears to have been facilitated by an onset of easterly winds in the\nNorthern Hemisphere subtropics of the upper stratosphere.\nE. Evaluation of Satellite Sampling of the Stratosphere\nA major source of data on the structure, chemistry, and dynamics of the\nstratosphere comes from nadir-viewing, polar-orbiting satellites. To determine\nthe types and magnitudes of errors to be expected in satellite sampling of\nthe middle atmosphere, the SKYHI seasonal cycle experiment (sec. II.D) is\n29","employed as a sample data set in which all variables are \"perfectly\" known.\nThis model data set is sampled in a way similar to that in which polar-\norbiting satellites sample the actual atmosphere.\nAlthough the research is in a comparatively early stage, it has been\ndetermined that sampling can provide fairly accurate temperature spatial\naverages (the basic variable). However, quantities that require derivatives\nof the temperature field become significantly worse as the order of dif-\nferentiation is increased. Thus, errors in quantities such as wind speed\nare noticeable, but acceptable, but quantities such as vorticity become\nunacceptably distorted. It is useful to know that in virtually all instances,\nthe sampling errors are considerably larger in lower latitudes.\nIII. Physical Processes in the Middle Atmosphere\nA. Radiative Transfer\nFor nearly a decade, GFDL has been developing a detailed and accurate\nradiative transfer model for use with SKYHI (e.g., Fels and Schwarzkopf,\n1981). In the past two years, several physical processes have been added:\nimproved CO2 transmission functions; the (H20)n continuum; and the effects of\nbreakdown of local thermodynamical equilibrium (important above 75 km).\nTo better understand the effect of radiative damping on the dynamics of\ndisturbances, a comprehensive calculation of scale-dependent radiative\ndamping on waves in the mesosphere was undertaken, extending previous work\n(Fels, 1982) to shorter wavelengths and greater altitudes. The effects of\nthe breakdown of local thermodynamic equilibrium were intentionally included.\nThe results are complicated in detail, but yield damping times of about 1.5\ndays for disturbances with vertical wavelength of 6 km in the mesosphere.\nSimple scaling laws were derived, allowing easy extension of the results to\nother CO2 mixing ratios. A doubling of the present CO2 loading in the\nmesosphere will typically lead to an increase of 40% in damping rates.\nB. Ozone Photochemistry\nFor the past several years, GFDL has collaborated with the Aeronomy\nLaboratory in an effort to combine a detailed ozone photochemistry model in\na self-consistent way with the radiation and dynamics in the GFDL SKYHI model\n(sec. II.A). The photochemical code has now been developed so that either\ndiurnal or diurnally averaged chemistry can be calculated. This allows far\nmore economical 3-D model calculations, while maintaining self-consistency\nwith the strongly diurnal character of stratospheric photochemistry.\nC. Seasonal March of Radiative-Photochemical Temperature\nThe radiation transfer and photochemistry models have been combined to\ninvestigate behavior of the middle atmosphere. The model has been applied\nto problems that require a completely self-consistently determined ozone and\ntemperature.\n30","To determine the joint radiative-photochemical equilibrium of the middle\natmosphere, the combined model has been run for 2 years at each of 20\nlatitudes. The solar insolation and surface temperature are specified as a\nfunction of season.\nThe results show generally good agreement with the comparable radiation-\nonly results obtained earlier by using specified ozone distribution. This\nagreement suggests that joint radiative-chemical-dynamical calculations may\nnow be planned with some confidence. Such calculations will allow a deter-\nmination of the degree to which dynamics and transport are involved in\nmaintaining the observed structure of ozone and temperature in the strato-\nsphere.\nIV. References\nAndrews, D. G., , J. D. Mahlman, and R. W. Sinclair, 1983. Eliassen-Palm\ndiagnostics of wave, mean-flow interaction in the GFDL \"SKYHI\"\ngeneral circulation model. J. Atmos. Sci., 40, 2768-2784.\nAndrews, D. G., , and M. E. McIntyre, 1976. Planetary waves in horizontal\nand vertical shear: The generalized Eliassen-Palm relation and the mean\nzonal acceleration. J. Atmos. Sci., 33, 2031-2048.\nDanielsen, E. F., , 1981. An objective method for determining the generalized\ntransport tensor for two-dimensional Eulerian models. J. Atmos.\nSci., 38, 1319-1339.\nFels, S. B., 1982. A parameterization of scale-dependent radiative\ndamping rates in the middle atmosphere. J. Atmos. Sci., , 39, 1141-\n1152.\nFels, S. B., M. D. Schwarzkopf, 1981. An efficient, accurate algorithm for\ncalculating CO2 15 um band cooling rates. J. Geophys. Res., 86,\n1205-1232.\nFels, S. B. , J. D. Mahlman, M. D. Schwarzkopf, and R. W. Sinclair, 1980.\nStratospheric sensitivity to perturbations in ozone and carbon dioxide:\nRadiative and dynamical response. J. Atmos. Sci., 37, 2265-2297.\nFrederick, J. E. , and J. E. Mentall, 1982. Solar irradiance in the strato-\nsphere: Implications for the Herzberg continuum absorption of 02.\nGeophys. Res. Lett., 9, 461-464.\nHirota, I., 1979. Kelvin waves in the equatorial middle atmosphere\nobserved by the Nimbus 5 SCR. J. Atmos. Sci., 36, 217-222.\nKley, D. , J. W. Drummond, M. McFarland, and S. C. Liu, 1981. Tropospheric\nprofiles of NO J. Geophys. Res., 86, 3153-3161.\nLevy II, H. J. D. Mahlman, and W. J. Moxim, 1980. A stratospheric source\nof reactive nitrogen in the unpolluted troposphere. Geophys. Res.\nLett., 7, 441-444.\n31","Levy II, H., J. D. Mahlman, and W. J. Moxim, 1982: Tropospheric N20 vari-\nability, J. Geophys. Res., 87, 3061-3080.\nLevy II, H., , J. D. Mahlman, S. C. Liu, and W. J. Moxim, 1984. Tropospheric\nozone: The role of transport. J. Geophys. Res. (to be submitted).\nLiu, S. C., D. Kley, M. McFarland, J. D. Mahlman, and H. Levy II, 1980.\nOn the origin of tropospheric ozone. J. Geophys. Res., , 85, 7546-7552.\nMahlman, J. D., 1975. Some fundamental limitations of simplified transport\nmodels as implied by results from a three-dimensional general-\ncirculation/tracer model. Proc. Fourth Conf. on CIAP (T. M. Hard and\nA. J. Broderick, eds.), DOT-TSC-OST-75-38 (NTIS AD-A068982) 132-146.\nMahlman, J. D., and W. J. Moxim, 1978. Tracer simulation using a global\ngeneral circulation model: Results from a midlatitude instantaneous\nsource experiment. J. Atmos. Sci., 35, 1340-1374.\nMahlman, J. D., and R. W. Sinclair, 1980. Recent results from the GFDL\ntroposphere-stratosphere-mesosphere general circulation model. Proc.\nIntl. Union Geodesy Geophys. (IUGG) Symposium 18, Twenty-Seventh IUGG\nGeneral Assembly, Dec. 1979, Canberra, Australia. NCAR, Boulder, Colo.,\npp. 11-18.\nMahlman, J. D., and L. J. Umscheid, 1984. Dynamics of the middle atmosphere:\nSuccesses and problems of the GFDL \"SKYHI\" general circulation model.\nProc. U.S.-Japan Seminar on Middle Atmosphere Dynamics. Terra Scientific\nPublishing Co., Tokyo (in press).\nMahlman, J. D., H. Levy II, and W. J. Moxim, 1980. Three-dimensional tracer\nstructure as simulated in two ozone precursor experiments.\nJ. Atmos. Sci., 37, 655-685.\nMahlman, J. D., H. Levy II, and W. J. Moxim, 1984. Three-dimensional\nsimulations of stratospheric N20: Predictions for other trace con-\nstituents. J. Geophys. Res. (to be submitted).\nManabe, S. and J. D. Mahlman, 1976. Simulation of seasonal and inter-\nhemispheric variations in the stratospheric circulation. J. Atmos. Sci.,\n33, 2185-2217.\nManabe, S., D. G. Hahn, and J. L. Holloway, Jr., 1974. The seasonal\nvariation of the tropical circulation as simulated by a global model\nof the atmosphere. J. Atmos. Sci., 31, 43-83.\nMatsuno, T., 1980. Lagrangian motion of air parcels in the stratosphere in\nthe presence of planetary waves. Pure Appl. Geophys., 118, 189-216.\nPlumb, R. A., 1979: Eddy fluxes of conserved quantities by small-amplitude\nwaves. J. Atmos. Sci., 36, 1699-1704.\nSalby, M. L., D. L. Hartmann, P. L. Bailey, and J. C. Gille, 1984. Evidence\nfor equatorial Kelvin modes in NIMBUS-7 LIMS. J. Atmos. Sci., 41 (in\npress)\n32","NATIONAL ENVIRONMENTAL SATELLITE, DATA,\nAND INFORMATION SERVICE\nBoulder, Colorado\nI. TIROS Operational Vertical Sounder Total Ozone\nTotal ozone amounts continue to be derived from radiance measurements\nobtained with the TIROS Operational Vertical Sounder (TOVS) on NOAA\noperational satellites. The satellites have provided ozone data for these\nperiods:\nTIROS-N: May 1979 - January 1981 (demise)\nNOAA 6: November 1979 - June 1983 (demise)\nNOAA 7: August 1981 - Present\nNOAA 8: August 1983 - Present\nThe data set of globally averaged total ozone amounts covers the period May\n1979 - March 1983. Analysis of this time series for trends has just begun.\nDuring routine evaluation of TOVS radiances, it was noted that processing\nof the channel sensitive to the 9.6-um ozone radiance introduced an error.\nAdjustments for limb darkening (i.e., the effect of increased atmospheric\nabsorption when the earth is observed at angles away from the nadir) were\nincorrect. A method of properly correcting for limb darkening has been\ndeveloped and is being evaluated for implementation by the operational\nprocessing system. In the meantime, radiances measured in the nadir view\nonly have been assembled, and total ozone amounts have been determined from\nthese. These data are archived and available from the NESDIS Satellite Data\nServices Division. The analyses discussed below are based on the corrected\nvalues.\nEvaluation of the data set for the period May 1979 to November 1982 is\ncurrently available. Total ozone amounts derived from TOVS data are compared\nwith those from Dobson and solar backscatter ultraviolet (SBUV) observations.\nComparison with a global, independent set of Dobson determinations on a\nmonthly basis yields correlation coefficients above 0.7 and generally between\n0.8 and 0.95. Standard deviations of the differences between TOVS and Dobson\ndeterminations vary between 5% and 8% for the same data set. Comparisons of a\nset of monthly global average total ozone with similar determinations from\nSBUV measurements show a bias of about 8.7% (TOVS being higher). This is\nconsistent with independent comparisons of SBUV and Dobson determinations done\non a sounding-by-sounding basis (Fleig et al., 1982) which showed an\nSBUV-Dobson bias of 8.3% (SBUV being higher). As TOVS-derived ozone amounts\nare based on Dobson measurements through the regression retrieval algorithm,\nthis result is expected. Figure 7 shows, for each instrument, the monthly\naverage total ozone amounts for the 0° -60°N zone (the correction for the\nSBUV-Dobson bias has been incorporated.\nWith the continuation of the globally averaged satellite data set into\n1983, the trend analysis will be extended and compared with trend analyses\nof data from other sources, particularly the Dobson network.\n33","320\n310\n300\n290\n280\nM J J A S O N D\nFigure 7. Total ozone determined by TOVS and SBUV for May-December\n1979. Values are monthly averages over the zone 0°-60°N. Solid curve is\nTOVS; dashed curve is SBUV corrected by a - 8.7 bias (SBUV minus\nDobson).\nII. Development and Implementation of Operational\nSolar Backscatter Ultraviolet Instruments\nThe first instrument for operational use has been delivered by the\ncontractor and is being installed on the NOAA-F spacecraft, which is due to\nbe launched about November 1984. SBUV sensors will be flown on only the\nmid-afternoon satellites (i.e., 2:20 p.m. local time equator crossing). These\nsatellites will also carry the Stratospheric Sounding Unit (SSU) capable of\nindependently deriving upper-stratospheric ozone profiles.\nDevelopment of the software system for operational retrieval has\nbegun. The system is based on the NASA Nimbus-7 SBUV retrieval algorithm,\nwhich will be modified to operate on NOAA computer facilities and to accept\nTIROS ancillary data needed in the retrieval algorithm. At present, the\noperational plan calls for satellite quick-look data products to be avail-\nable 2 months after launch of the NOAA-F spacecraft.\nIII. Reference\nFleig, A. J., , K. F. . Klenk, P. K. Bhartia, D. Gordon, and W. H. Schneider,\n1982. User's Guide for the SBUV Instrument First-Year Data Set, NASA\nReference Publication 1095, 72 pp.\n34","NATIONAL WEATHER SERVICE\nClimate Analysis Center\nCamp Springs, Maryland\nDuring 1982-1983, efforts of the Climate Analysis Center, Analysis and\nInformation Branch (AIB), have been concentrated on two main areas: (1)\noperational stratospheric monitoring of temperature, pressure heights, and\nozone and (2) analysis of available data for trends.\nI. Operational Stratospheric Monitoring\nDaily (1200 GMT) global meteorological analyses of height and temperature\nat 70, 50, 30, 10, 5, 2, 1, and 0.4 mb (20-55 km) continue to be constructed.\nDuring the last 2 years we have modified the analysis procedure to include\nsatellite data in the lower stratosphere and also have implemented a rocket-\nsonde-analysis comparison program to provide for long-term calibration\n(Gelman et al., 1983).\nIn addition to the archive of the analyses themselves, we have estab-\nlished an archive of several derived parameters. These include the zonal\naverage values of wind, temperature, kinetic energy, and eddy transports of\nsensible heat and momentum. Daily and monthly values are being determined for\nall levels being analyzed (e.g., Geller et al., 1983).\nDaily (1200 GMT) global analyses from the TIROS operational Vertical\nSounder (TOVS) continue to be constructed. The results for the period May\n1979 to November 1982, integrated over the data domain 60°N-60°S, indicate a\nmarked decrease of about 3% during this period. This trend is under\nevaluation.\nPlanning was begun for the data flow and verification techniques to be\nimplemented with the launch of the SBUV-2 instrument on NOAA-F in November\n1984. This instrument is an operational version of the Nimbus-7 SBUV and will\nprovide the basic ozone data set required for the early detection of change.\nII. Examination of Ozone Data for Trends\nMonthly average global synoptic analyses of total ozone and ozone\nmixing ratio at 30, 10, 5, 2, and 1 mb for the period April 1970 to December\n1976 from Nimbus-4 BUV data have been archived at the National Space Science\nData Center. An examination of the temporal variation found no significant\ntrend in total ozone in the Northern Hemisphere during this period (Miller et\nal., 1982).\nDaily and monthly average global synoptic analyses of total ozone and\nozone mixing ratio at 30, 10, 5, 2, 1, and 0.4 mb for the period November\n1978 to October 1980 from Nimbus-7 SBUV data have been archived at the\nNational Space Science Data Center. Analyses for the third and fourth years\nare in preparation.\n35","LYR\nMB\n9\nI-2\n8\n2-4\n7\n4-8\n(1983)\nREINSEL ET AL\n6\n8-16\nWUEBBLES\nWUEBBLES ET AL\n5\n16-32\n-6\n-5\n-4\n-3\n-2\n-1\nO\n%\nFigure 8. Ozone decadal trend, 1970-1980.\nAs part of the overall effort to determine not only the observed\nstratospheric changes but a delineation of the causes of the changes, a\nprogram was initiated to use the ozone and meteorological analyses to compute\nozone transports and ozone-temperature associations (Miller et al. , 1983;\nNagatani and Miller, 1984). These first results are very encouraging in that\nthey show general agreement with numerical model calculations. This program\nwill be continued.\nTo evaluate global trends of ozone at stratospheric levels, connection\nbetween BUV data ('70- 76) and SBUV data ('78-present) must be made through\nthe ground-based Umkehr network. In cooperation with Professors George Tiao\n(University of Chicago) and Gregory Reinsel (University of Wisconsin), John\nFrederick (NASA), , John DeLuisi (NOAA), and Carl Mateer (AES, Canada), we have\nexamined these data as the first step in achieving a total, consistent data\nset. Utilizing a statistical technique that includes effects for\nstratospheric aerosol impact on the Umkehr data, trends (1970-1980) were\ndetermined and compared with numerical model calculations of Wuebbles et al.\n(1983) and Wuebbles (1983). The results, published by Reinsel et al. (1984),\nare depicted in Figure 8. There is good agreement between observation and\ntheory. This is the first such documented observational indication of a\npossible anthropogenic impact on the ozone layer. Considerable effort remains\nto compare these results with the global satellite data.\n36","Currently, the Solar Backscatter Ultraviolet data analysis technique is\nlimited at the lower level by our ability to consider single versus multiple\nscattering in the retrieval algorithm. Consequently, a statistical regression\ntechnique has been developed to derive ozone profile information in the lower\nstratosphere and upper troposphere. The ozone amount in the lower\nstratosphere - upper troposphere is deduced from the difference between the\nmeasured total ozone and that measured above 30 mb. The vertical variation\nwithin the lower stratosphere - upper troposphere region is determined by\nregression against an historical set of ozone balloon profiles. A report is\nin preparation.\nIII. References\nGelman, M. E., A. J. Miller, R. M. Nagatani, and H. D. Bowan II, 1983.\nMean zonal wind and temperature structure during the PMP-1 winter\nperiods. Adv. Space Res., 2, 159-162.\nGeller, M. A., Mao-Fou Wu, and M. E. Gelman, 1983. Troposphere-stratosphere\n(surface - 55 km) monthly winter general circulation statistics for the\nNorthern Hemisphere - four year averages. J. Atmos. Sci., 40, 1334-1352.\nHeath, D. F., A. J. Fleig, A. J. Miller, T. G. Rogers, R. M. Nagatani, H. D.\nBowman II, V. G. Kaueeshwar, K. F. Klenk, P. K. Bhartia, and K. D. Lee,\n1982. Ozone Climatology Series, Volume 1, Atlas of Total Ozone: April\n1970 - December 1976. NASA Reference Publication 1098, 163 pp.\nMiller, A. J., R. M. Nagatani, T. G. Rogers, A. J. Fleig, and D. F. Heath,\n1982. Total ozone variations 1970 - 1974 using background ultraviolet\n(BUV) and ground-based observations. J. Appl. Meteor., 21, 621-630.\nMiller, A. J. R. M. Nagatani, and M. E. Gelman, 1983. Meteorological\ninfluences on ozone distribution during the stratospheric warming of\nJanuary-February 1979 - Part II. Paper presented at 4th Conference on\nthe Meteorology of the Upper Atmosphere, Boston, Mass., March 22-25,\n1983, American Meteorological Society.\nNagatani, R. M., and A. J. Miller, 1984. Stratospheric ozone changes during\nthe first year of SBUV observations. J. Geophys. Res., 89, 5191-5198.\nReinsel, G. C., G. C. Tiao, J. J. DeLuisi, C. L. Mateer, A. J. Miller, and\nJ. E. Frederick, 1984. Analysis of upper stratospheric Umkehr ozone\nprofile data for trends and effects of stratospheric aerosols. J.\nGeophys. Res., 89, 4833-4840.\nWuebbles, D. J,, F. M. Luther, and J. E. Penner, 1983. Effect of coupled\nanthropogenic perturbations on stratospheric ozone. J. Geophys. Res., 88,\n1444-1456.\nWuebbles, D. J., 1983. A theoretical analysis of the past variations in global\natmospheric composition and temperature structure. Lawrence Livermore\nLaboratory Report UCRL-53423, 161 pp.\n37"]}