The Community Atmosphere Model (CAM), version 5, is now coupled to extensive tropospheric and stratospheric chemistry, called CAM5-chem, and is available in addition to CAM4-chem in the Community Earth System Model (CESM) version 1.2. The main focus of this paper is to compare the performance of configurations with internally derived "free running" (FR) meteorology and "specified dynamics" (SD) against observations from surface, aircraft, and satellite, as well as understand the origin of the identified differences. We focus on the representation of aerosols and chemistry. All model configurations reproduce tropospheric ozone for most regions based on in situ and satellite observations. However, shortcomings exist in the representation of ozone precursors and aerosols. Tropospheric ozone in all model configurations agrees for the most part with ozonesondes and satellite observations in the tropics and the Northern Hemisphere within the variability of the observations. Southern hemispheric tropospheric ozone is consistently underestimated by up to 25 %. Differences in convection and stratosphere to troposphere exchange processes are mostly responsible for differences in ozone in the different model configurations. Carbon monoxide (CO) and other volatile organic compounds are largely underestimated in Northern Hemisphere mid-latitudes based on satellite and aircraft observations. Nitrogen oxides (NOx) are biased low in the free tropical troposphere, whereas peroxyacetyl nitrate (PAN) is overestimated in particular in high northern latitudes. The present-day methane lifetime estimates are compared among the different model configurations. These range between 7.8 years in the SD configuration of CAM5-chem and 8.8 years in the FR configuration of CAM4-chem and are therefore underestimated compared to observational estimations. We find that differences in tropospheric aerosol surface area between CAM4 and CAM5 play an important role in controlling the burden of the tropical tropospheric hydroxyl radical (OH), which causes differences in tropical methane lifetime of about half a year between CAM4-chem and CAM5-chem. In addition, different distributions of NOx from lightning explain about half of the difference between SD and FR model versions in both CAM4-chem and CAM5-chem. Remaining differences in the tropical OH burden are due to enhanced tropical ozone burden in SD configurations compared to the FR versions, which are not only caused by differences in chemical production or loss but also by transport and mixing. For future studies, we recommend the use of CAM5-chem configurations, due to improved aerosol description and inclusion of aerosol-cloud interactions. However, smaller tropospheric surface area density in the current version of CAM5-chem compared to CAM4-chem results in larger oxidizing capacity in the troposphere and therefore a shorter methane lifetime.
Wells, K. C.; Millet, D. B.; Bousserez, N.; Henze, D. K.; Griffis, T. J.; Chaliyakunnel, S.; Dlugokencky, E. J.; Saikawa, E.; Xiang, G.; Prinn, R. G.; O'Doherty, S.; Young, D.; Weiss, R. F.; Dutton, G. S.; Elkins, J. W.; Krummel, P. B.; Langenfelds, R.; Steele, L. P.;
Published Date:
2018
Source:
Atmospheric Chemistry and Physics, 18(2), 735-756.
Description:
We present top-down constraints on global monthly N2O emissions for 2011 from a multi-inversion approach and an ensemble of surface observations. The inversions employ the GEOS-Chem adjoint and an array of aggregation strategies to test how well curr...
Raczka, B.; Biraud, S. C.; Ehleringer, J. R.; Lai, C. T.; Miller, J. B.; Pataki, D. E.; Saleska, S. R.; Torn, M. S.; Vaughn, B. H.; Wehr, R.; Bowling, D. R.;
Published Date:
2017
Source:
Journal of Geophysical Research-Biogeosciences, 122(8), 1969-1987.
Description:
The seasonal pattern of the carbon isotope content (delta C-13) of atmospheric CO2 depends on local and nonlocal land-atmosphere exchange and atmospheric transport. Previous studies suggested that the delta C-13 of the net land-atmosphere CO2 flux (d...
Journal of Geophysical Research-Atmospheres, 123(15), 7950-7973.
Description:
In this study, we analyze a set of agroclimatological indices across West Africa and assess their projected changes for the future. We apply the regional climate model CCLM (COnsortium for Small-scale MOdelling in CLimate Mode) with a high spatial re...
Kenagy, H. S.; Sparks, T. L.; Ebben, C. J.; Wooldrige, P. J.; Lopez-Hilfiker, F. D.; Lee, B. H.; Thornton, J. A.; McDuffie, E. E.; Fibiger, D. L.; Brown, S. S.; Montzka, D. D.; Weinheimer, A. J.; Schroder, J. C.; Campuzano-Jost, P.; Day, D. A.; Jimenez, J. L.; Dibb, J. E.; Campos, T.; Shah, V.; Jaegle, L.; Cohen, R. C.;
Published Date:
2018
Source:
Journal of Geophysical Research-Atmospheres, 123(17), 9813-9827.
Description:
Although urban NOx lifetimes have been examined extensively during summertime conditions, wintertime NOx chemistry has been comparatively less studied. We use measurements of NOx and its oxidation products from the aircraft-based WINTER (Wintertime I...
Jarvinen, E.; Ignatius, K.; Nichman, L.; Kristensen, T. B.; Fuchs, C.; Hoyle, C. R.; Hoppel, N.; Corbin, J. C.; Craven, J.; Duplissy, J.; Ehrhart, S.; El Haddad, I.; Frege, C.; Gordon, H.; Jokinen, T.; Kallinger, P.; Kirkby, J.; Kiselev, A.; Naumann, K. H.; Petaja, T.; Pinterich, T.; Prevot, A. S. H.; Saathoff, H.; Schiebel, T.; Sengupta, K.; Simon, M.; Slowik, J. G.; Trostl, J.; Virtanen, A.; Vochezer, P.; Vogt, S.; Wagner, A. C.; Wagner, R.; Williamson, C.; Winkler, P. M.; Yan, C.; Baltensperger, U.; Donahue, N. M.; Flagan, R. C.; Gallagher, M.; Hansel, A.; Kulmala, M.; Stratmann, F.; Worsnop, D. R.; Mohler, O.; Leisner, T.; Schnaiter, M.;
Published Date:
2016
Source:
Atmospheric Chemistry and Physics, 16(7), 4423-4438.
Description:
Under certain conditions, secondary organic aerosol (SOA) particles can exist in the atmosphere in an amorphous solid or semi-solid state. To determine their relevance to processes such as ice nucleation or chemistry occurring within particles requir...
Butler, R.; Palmer, P. I.; Feng, L.; Andrews, S. J.; Atlas, E. L.; Carpenter, L. J.; Donets, V.; Harris, N. R. P.; Montzka, S. A.; Pan, L. L.; Salawitch, R. J.; Schauffler, S. M.;
Published Date:
2018
Source:
Atmospheric Chemistry and Physics, 18(17), 13135-13153.
Description:
We use the GEOS-Chem global 3-D atmospheric chemistry transport model to interpret atmospheric observations of bromoform (CHBr3) and dibromomethane (CH2Br2) collected during the CAST and CONTRAST aircraft measurement campaigns over the western Pacifi...
Fried, A.; Barth, M. C.; Bela, M.; Weibring, P.; Richter, D.; Walega, J.; Li, Y.; Pickering, K.; Apel, E.; Hornbrook, R.; Hills, A.; Riemer, D. D.; Blake, N.; Blake, D. R.; Schroeder, J. R.; Luo, Z. J.; Crawford, J. H.; Olson, J.; Rutledge, S.; Betten, D.; Biggerstaff, M. I.; Diskin, G. S.; Sachse, G.; Campos, T.; Flocke, F.; Weinheimer, A.; Cantrell, C.; Pollack, I.; Peischl, J.; Froyd, K.; Wisthaler, A.; Mikoviny, T.; Woods, S.;
Published Date:
2016
Source:
Journal of Geophysical Research-Atmospheres, 121(12), 7430-7460.
Description:
We have developed semi-independent methods for determining CH2O scavenging efficiencies (SEs) during strong midlatitude convection over the western, south-central Great Plains, and southeastern regions of the United States during the 2012 Deep Convec...
Janssens-Maenhout, G.; Crippa, M.; Guizzardi, D.; Dentener, F.; Muntean, M.; Pouliot, G.; Keating, T.; Zhang, Q.; Kurokawa, J.; Wankmuller, R.; van der Gon, H. D.; Kuenen, J. J. P.; Klimont, Z.; Frost, G.; Darras, S.; Koffi, B.; Li, M.;
Published Date:
2015
Source:
Atmospheric Chemistry and Physics, 15(19), 11411-11432.
Description:
The mandate of the Task Force Hemispheric Transport of Air Pollution (TF HTAP) under the Convention on Long-Range Transboundary Air Pollution (CLRTAP) is to improve the scientific understanding of the intercontinental air pollution transport, to quan...
Brown, S. S.; Dube, W. P.; Tham, Y. J.; Zha, Q. Z.; Xue, L. K.; Poon, S.; Wang, Z.; Blake, D. R.; Tsui, W.; Parrish, D. D.; Wang, T.;
Published Date:
2016
Source:
Journal of Geophysical Research-Atmospheres, 121(5), 2457-2475.
Description:
Nighttime reactions of nitrogen oxides influence ozone, volatile organic compounds, and aerosol and are thus important to the understanding of regional air quality. Despite large emissions and rapid recent growth of nitrogen oxide concentrations, the...
Kim, J.; Johnson, L. E.; Cifelli, R.; Choi, J.; Chandrasekar, V.;
Published Date:
2018
Source:
Water, 10(7), 21.
Description:
Soil moisture retention (SMR) capacity plays a key role in estimating the direct runoff when a multi-pulse storm event occurs. It is very important to know how much SMR will be recovered during the intervals of no rain of a multi-pulse storm. This st...
Fairall, C. W.; Matrosov, S. Y.; Williams, C. R.; Walsh, E. J.;
Published Date:
2018
Source:
Journal of Atmospheric and Oceanic Technology, 35(3), 593-608.
Description:
The NOAA W-band radar was deployed on a P-3 aircraft during a study of storm fronts off the U.S. West Coast in 2015 in the second CalWater (CalWater-2) field program. This paper presents an analysis of measured equivalent radar reflectivity factor Z(...
A 4-year record of aerosol size and hygroscopic growth factor distributions measured at the Department of Energy's Southern Great Plains (SGP) site in Oklahoma, U.S. were used to estimate supersaturation (S)-dependent cloud condensation nuclei concen...
Mahoney, K.; Swales, D.; Mueller, M. J.; Alexander, M.; Hughes, M.; Malloy, K.;
Published Date:
2018
Source:
Journal of Climate, 31(16), 6281-6297.
Description:
Atmospheric rivers (ARs) are well-known producers of precipitation along the U.S. West Coast. Depending on their intensity, orientation, and location of landfall, some ARs penetrate inland and cause heavy rainfall and flooding hundreds of miles from ...
Dimdore-Miles, O. B.; Palmer, P. I.; Bruhwiler, L. P.;
Published Date:
2018
Source:
Atmospheric Chemistry and Physics, 18(24), 17895-17907.
Description:
We consider the utility of the annual inter-polar difference (IPD) as a metric for changes in Arctic emissions of methane (CH4). The IPD has been previously defined as the difference between weighted annual means of CH4 mole fraction data collected a...
Sea surface temperature anomalies (SSTA) in portions of the extratropics are known to recur from one winter to the next without persisting through the intervening summer. Previous studies identified only a limited number of midlatitude regions where ...
Richardson, K.; Asmutis-Silvia, R.; Drinkwin, J.; Gilardi, K. V. K.; Giskes, I.; Jones, G.; O'Brien, K.; Pragnell-Raasch, H.; Ludwig, L.; Antonelis, K.; Barco, S.; Henry, A.; Knowlton, A.; Landry, S.; Mattila, D.; MacDonald, K.; Moore, M.; Morgan, J.; Robbins, J.; van der Hoop, J.; Hogan, E.;
Published Date:
2019
Source:
Marine Pollution Bulletin, 138, 222-229.
Description:
Abandoned, lost or discarded fishing gear (ALDFG) comprises a significant amount of global marine debris, with diverse impacts to marine environments, wildlife, and the fishing industry. Building evidence on ALDFG is critical to holistically understa...
Smith, M.; Stammerjohn, S.; Persson, O.; Rainville, L.; Liu, G. Q.; Perrie, W.; Robertson, R.; Jackson, J.; Thomson, J.;
Published Date:
2018
Source:
Journal of Geophysical Research-Oceans, 123(5), 3164-3185.
Description:
High-resolution measurements of the air-ice-ocean system during an October 2015 event in the Beaufort Sea demonstrate how stored ocean heat can be released to temporarily reverse seasonal ice advance. Strong on-ice winds over a vast fetch caused mixi...
Chakraborty, A.; Ervens, B.; Gupta, T.; Tripathi, S. N.;
Published Date:
2016
Source:
Journal of Geophysical Research-Atmospheres, 121(8), 4317-4332.
Description:
Size-resolved fog water samples were collected in two consecutive winters at Kanpur, a heavily polluted urban area of India. Samples were analyzed by an aerosol mass spectrometer after drying and directly in other instruments. Residues of fine fog dr...
Kim, P. S.; Jacob, D. J.; Fisher, J. A.; Travis, K.; Yu, K.; Zhu, L.; Yantosca, R. M.; Sulprizio, M. P.; Jimenez, J. L.; Campuzano-Jost, P.; Froyd, K. D.; Liao, J.; Hair, J. W.; Fenn, M. A.; Butler, C. F.; Wagner, N. L.; Gordon, T. D.; Welti, A.; Wennberg, P. O.; Crounse, J. D.; St. Clair, J. M.; Teng, A. P.; Millet, D. B.; Schwarz, J. P.; Markovic, M. Z.; Perring, A. E.;
Heiblum, R. H.; Altaratz, O.; Koren, I.; Feingold, G.; Kostinski, A. B.; Khain, A. P.; Ovchinnikov, M.; Fredj, E.; Dagan, G.; Pinto, L.; Yaish, R.; Chen, Q.;
Published Date:
2016
Source:
Journal of Geophysical Research-Atmospheres, 121(11), 6336-6355.
Description:
We study the evolution of warm convective cloud fields using large eddy simulations of continental and trade cumulus. Individual clouds are tracked a posteriori from formation to dissipation using a 3-D cloud-tracking algorithm, and results are prese...
Rollins, A. W.; Thornberry, T. D.; Watts, L. A.; Yu, P.; Rosenlof, K. H.; Mills, M.; Baumann, E.; Giorgetta, F. R.; Bui, T. V.; Hopfner, M.; Walker, K. A.; Boone, C.; Bernath, P. F.; Colarco, P. R.; Newman, P. A.; Fahey, D. W.; Gao, R. S.;
Published Date:
2017
Source:
Geophysical Research Letters, 44(9), 4280-4286.
Description:
Stratospheric aerosols (SAs) are a variable component of the Earth's albedo that may be intentionally enhanced in the future to offset greenhouse gases (geoengineering). The role of tropospheric-sourced sulfur dioxide (SO2) in maintaining background ...
Solomon, S.; Kinnison, D.; Garcia, R. R.; Bandoro, J.; Mills, M.; Wilka, C.; Neely, R. R.; Schmidt, A.; Barnes, J. E.; Vernier, J. P.; Hopfner, M.;
Published Date:
2016
Source:
Geophysical Research Letters, 43(24), 12624-12633.
Description:
Model simulations presented in this paper suggest that transport processes associated with the summer monsoons bring increased abundances of hydrochloric acid into contact with liquid sulfate aerosols in the cold tropical lowermost stratosphere, lead...