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1. Emission estimates of HCFCs and HFCs in California from the 2010 CalNex study

Author

Barletta, B, Carreras-Sospedra, M, Cohan, A, Nissenson, P, Dabdub, D, Meinardi, S, Atlas, E, Lueb, R, Holloway, JS, Ryerson, TB, Pederson, J, Vancuren, RA, and Blake, DR

Subjects
Atmospheric Sciences, Physical Geography and Environmental Geoscience
Abstract

The CalNex 2010 (California Research at the Nexus of Air Quality and Climate Change) study was designed to evaluate the chemical composition of air masses over key source regions in California. During May to June 2010, air samples were collected on board a National Oceanic and Atmospheric Administration (NOAA) WP-3D aircraft over the South Coast Air Basin of California (SoCAB) and the Central Valley (CV). This paper analyzes six effective greenhouse gases - chlorodifluoromethane (HCFC-22), 1,1-dichloro-1-fluoroethane (HCFC-141b), 1-chloro-1,1-difluoroethane (HCFC-142b), 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124), 1,1,1,2- tetrafluoroethane (HFC-134a), and 1,1-difluoroethane (HFC-152a) - providing the most comprehensive characterization of chlorofluorocarbon (CFC) replacement compound emissions in California. Concentrations of measured HCFCs and HFCs are enhanced greatly throughout the SoCAB and CV, with highest levels observed in the SoCAB: 310 ± 92 pptv for HCFC-22, 30.7 ± 18.6 pptv for HCFC-141b, 22.9 ± 2.0 pptv for HCFC-142b, 4.86 ± 2.56 pptv for HCFC-124, 109 ± 46.4 pptv for HFC-134a, and 91.2 ± 63.9 pptv for HFC-152a. Annual emission rates are estimated for all six compounds in the SoCAB using the measured halocarbon to carbon monoxide (CO) mixing ratios and CO emissions inventories. Emission rates of 3.05 ± 0.70 Gg for HCFC-22, 0.27 ± 0.07 Gg for HCFC-141b, 0.06 ± 0.01 Gg for HCFC-142b, 0.11 ± 0.03 Gg for HCFC-124, 1.89 ± 0.43 Gg for HFC-134a, and 1.94 ± 0.45 Gg for HFC-152b for the year 2010 are calculated for the SoCAB. These emissions are extrapolated from the SoCAB region to the state of California using population data. Results from this study provide a baseline emission rate that will help future studies determine if HCFC and HFC mitigation strategies are successful. Key PointsHCFC and HFC emissions are calculated for the year 2010 for the SoCABEmissions are extrapolated to the state of CaliforniaEmissions are calculated using CalNex field measurements © 2013. American Geophysical Union. All Rights Reserved.

Published
2013

2. Organic Aerosol Formation Downwind from the Deepwater Horizon Oil Spill

Author

de Gouw, J. A., Middlebrook, A. M., Warneke, C., Ahmadov, R., Atlas, E. L., Bahreini, R., Blake, D. R., Brock, C. A., Brioude, J., Fahey, D. W., Fehsenfeld, F. C., Holloway, J. S., Le Henaff, M., Lueb, R. A., McKeen, S. A., Meagher, J. F., Murphy, D. M., Paris, C., Parrish, D. D., Perring, A. E., Pollack, I. B., Ravishankara, A. R., Robinson, A. L., Ryerson, T. B., Schwarz, J. P., Spackman, J. R., Srinivasan, A., and Watts, L. A.

Published
2011
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3. An Examination of Chemistry and Transport Processes in the Tropical Lower Stratosphere Using Observations of Long-Lived and Short-Lived Compounds Obtained During STRAT and POLARIS

Author

Bui, T, Blake, D, Scott, D, Rosenlof, K, Moyer, E, May, R, Lueb, R, Schauffler, S, Webster, C, Atlas, E, Salawitch, R, Flocke, F, and Herman, R

Abstract

The entrainment time scale in our study is considerably less than the value found by a similar study that focused on observations obtained in the lower stratosphere during 1994.

Published
1998

4. BrO and Bry profiles over the Western Pacific : Relevance of Inorganic Bromine Sources and a Bry Minimum in the Aged Tropical Tropopause Layer

Author

Koenig, T. K., Volkamer, R., Baidar, S., Dix, B., Anderson, D. C., Salawitch, R. J., Wales, P. A., Cuevas, C. A., Fernandez, R. P., Saiz-Lopez, A., Evans, M. J., Sherwen, T., Jacob, D. J., Schmidt, J., Kinnison, D., Lamarque, J.-F., Apel, E. C., Bresch, J. C., Campos, T., Flocke, F. M., Honomichl, S. B., Hornbrook, R., Jensen, J. B., Lueb, R., Montzka, D. D., Pan, L. L., Reeves, J. M., Schauffler, S. M., Ullmann, K., Weinheimer, A. J., Atlas, E. L., Donets, V., Navarro, M. A., Riemer, D., Blake, N. J., Huey, L. G., Tanner, D. J., Hanisco, T. F., Wolfe, G. M., Wang, Siyuan, Chen, Dexien, and Hall, Samuel R.

Subjects
purl.org/becyt/ford/1 [https], BrO and Bry, purl.org/becyt/ford/1.5 [https], CONTRAST, Stratospheric Injection, Meteorología y Ciencias Atmosféricas, CIENCIAS NATURALES Y EXACTAS, VSL Chemistry, Ciencias de la Tierra y relacionadas con el Medio Ambiente
Abstract

We report measurements of bromine monoxide (BrO) and use an observationally constrained chemical box-model to infer total gas phase inorganic bromine (Bry) over the tropical Western Pacific Ocean (tWPO) during the CONTRAST field 40 campaign (January – February 2014). The median tropospheric BrO Vertical Column Density (VCD) over the tWPO was measured as 1.6×1013 molec. cm˗2, compared to model predictions of 0.4×1013 in CAM-Chem, 0.9×1013 in GEOS-Chem, and 2.1×1013 in GEOS-Chem with a sea-salt aerosol (SSA) bromine source. The observed BrO and inferred Bry profiles is found to be C-shaped in the troposphere, with local maxima in the marine boundary layer (MBL) and in the upper free troposphere. Neither global model fully captures this profile shape. Between 6 and 13.5 km, the inferred Bry is highly sensitive to 5 assumptions about the rate of heterogeneous bromine recycling (depends on the surface area of ice/aerosols), and the inclusion of a SSA bromine source. A local Bry maximum of 3.6 ppt (2.3-11.1 ppt, 95% CI) is observed between 9.5 and 13.5 km in air masses influenced by recent convective outflow. Unlike BrO, which increases from the convective TTL to the aged TTL, gas phase Bry decreases from the convective TTL to the aged TTL. Analysis of gas phase Bry against multiple tracers (CFC-11, H2O/O3 ratio, and θ) reveals a Bry minimum of 2.7 ppt (2.4-3.0 ppt, 95% CI) in the aged TTL, which is remarkably insensitive 10 to assumptions about heterogeneous chemistry. Bry increases to 6.3 ppt (5.9-6.7 ppt, 95% CI) in the stratospheric middleworld, and 6.9 ppt (6.7-7.1 ppt, 95% CI) in the stratospheric overworld. The local Bry minimum in the aged TTL is qualitatively (but not quantitatively) captured by CAM-chem, and suggests a more complex partitioning of gas phase and aerosol Bry species than previously recognized. Our data provide corroborating evidence that inorganic bromine sources (e.g., SSA derived gas phase Bry) are needed to explain the gas phase Bry budget in the TTL. They are also consistent with observations of significant 15 bromide in UTLS aerosols. The total Bry budget in the TTL is currently not closed, because of the lack of concurrent quantitative measurements of gas phase Bry species (i.e., BrO, HOBr, HBr, etc.) and aerosol bromide. These simultaneous measurements are needed 1) to quantify SSA derived Bry aloft, 2) to test Bry partitioning, and explain the gas phase Bry minimum in the aged TTL, 3) to constrain heterogeneous reaction rates of bromine, and 4) to account for all of the sources of Bry to the lower stratosphere. Fil: Koenig, Theodore K.. State University of Colorado at Boulder; Estados Unidos. Cooperative Institute for Research in Environmental Sciences; Estados Unidos Fil: Volkamer, Rainer. State University of Colorado at Boulder; Estados Unidos. Cooperative Institute for Research in Environmental Sciences; Estados Unidos Fil: Baidar, Sunil. Cooperative Institute for Research in Environmental Sciences; Estados Unidos. State University of Colorado at Boulder; Estados Unidos Fil: Dix, Barbara. State University of Colorado at Boulder; Estados Unidos Fil: Wang, Siyuan. State University of Colorado at Boulder; Estados Unidos. University of Michigan; Estados Unidos Fil: Anderson, Daniel C.. University of Maryland. Department of Atmospheric and Oceanic Science; Estados Unidos Fil: Salawitch, Ross J.. University of Maryland. Department of Atmospheric and Oceanic Science; Estados Unidos Fil: Wales, Pamela A.. University of Maryland. Department of Atmospheric and Oceanic Science; Estados Unidos Fil: Cuevas, Carlos A.. Consejo Superior de Investigaciones Científicas. Instituto de Química Física; España Fil: Fernandez, Rafael Pedro. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Universidad Tecnologica Nacional. Facultad Regional Mendoza. Secretaría de Ciencia, Tecnología y Postgrado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina Fil: Saiz Lopez, Alfonso. Consejo Superior de Investigaciones Científicas. Instituto de Química Física; España Fil: Evans, Mathew J.. University of York; Reino Unido Fil: Sherwen, Tomás. University of York; Reino Unido Fil: Jacob, Daniel J.. Harvard University; Estados Unidos Fil: Schmidt, Johan. Universidad de Copenhagen; Dinamarca Fil: Kinnison, Douglas. National Center for Atmospheric Research; Estados Unidos Fil: Lamarque, Jean François. National Center for Atmospheric Research; Estados Unidos Fil: Apel, Eric C.. National Center for Atmospheric Research; Estados Unidos Fil: Bresch, James C.. National Center for Atmospheric Research; Estados Unidos Fil: Campos, Teresa. National Center for Atmospheric Research; Estados Unidos Fil: Flocke, Frank M.. National Center for Atmospheric Research; Estados Unidos Fil: Hall, Samuel R.. National Center for Atmospheric Research; Estados Unidos Fil: Honomichl, Shawn B.. National Center for Atmospheric Research; Estados Unidos Fil: Hornbrook, Rebecca. National Center for Atmospheric Research; Estados Unidos Fil: Jensen, Jorgen B.. National Center for Atmospheric Research; Estados Unidos Fil: Lueb, Richard. National Center for Atmospheric Research; Estados Unidos Fil: Montzka, Denise D.. National Center for Atmospheric Research; Estados Unidos Fil: Pan, Laura L.. National Center for Atmospheric Research; Estados Unidos Fil: Reeves, J. Michael. National Center for Atmospheric Research; Estados Unidos Fil: Schauffle, Sue M.. National Center for Atmospheric Research; Estados Unidos Fil: Ullmann, Kirk. National Center for Atmospheric Research; Estados Unidos Fil: Weinheimer, Andrew J.. National Center for Atmospheric Research; Estados Unidos Fil: Atlas, Elliot L.. University of Miami; Estados Unidos Fil: Donets, Valeria. University of Miami; Estados Unidos Fil: Maria A. Navarro. University of Miami; Estados Unidos Fil: Riemer, Daniel. University of Miami; Estados Unidos Fil: Blake, Nicola J.. University of California; Estados Unidos Fil: Chen, Dexien. School of Earth & Atmospheric Sciences; Estados Unidos Fil: Huey, L. Gregory. School of Earth & Atmospheric Sciences; Estados Unidos Fil: Tanner, David J.. School of Earth & Atmospheric Sciences; Estados Unidos Fil: Hanisco, Thomas F.. National Aeronautics and Space Administration; Estados Unidos Fil: Wolfe, Glenn M.. University of Maryland; Estados Unidos. National Aeronautics and Space Administration; Estados Unidos

Published
2017

5. Measurements of halogenated organic compounds near the tropical tropopause

Author

Schauffler, S. M, Heidt, L. E, Pollock, W. H, Gilpin, T. M, Vedder, J. F, Solomon, S, Lueb, R. A, and Atlas, E. L

Subjects
Geophysics
Abstract

The amount of organic chlorine and bromine entering the stratosphere have a direct influence on the magnitude of chlorine and bromine catalyzed ozone losses. Twelve organic chlorine species and five organic bromine species were measured from 12 samples collected near the tropopause between 23.8 deg N and 25.3 deg N during AASE 2. The average mixing ratios of total organic chlorine and total organic bromine were 3.50 +/- 0.06 ppbv and 21.1 +/- 0.8 pptv, respectively. CH3Cl represented 15.1% of the total organic chlorine, with CFC 11 (CCl3F) and CFC 12 (CCl2F2) accounting for 22.6% and 28.2%, respectively, with the remaining 34.1% primarily from CCl4, CH3CCl3, and CFC 113 (CCl2FCClF2). CH3Br represented 54% of the total organic bromine. The 95% confidence intervals of the mixing ratios of all but four of the individual compounds were within the range observed in low and mid-latitude mid-troposphere samples. The four compounds with significantly lower mixing ratios at the tropopause were CHCl3, CH2Cl2, CH2Br2, and CH3CCl3. The lower mixing ratios may be due to entrainment of southern hemisphere air during vertical transport in the tropical region and/or to exchange of air across the tropopause between the lower stratosphere and upper troposphere.

Published
1993

6. On the age of stratospheric air and ozone depletion potentials in polar regions

Author

Pollock, W. H, Heidt, L. E, Lueb, R. A, Vedder, J. F, Mills, M. J, and Solomon, S

Subjects
Geophysics
Abstract

Observations of the nearly inert, man-made chlorofluorocarbon CFC-115 obtained during January 1989 are used to infer the age of air in the lower stratosphere. These observations together with estimated release rates suggest an average age of high-latitude air at pressure altitudes near 17-21 km of about 3 to 5 yr. This information is used together with direct measurements of HCFC-22, HCFC-142b, CH3Br, H-1301, H-1211, and H-2402 to examine the fractional dissociation of these species within the Arctic polar lower stratosphere compared to that of CFC-11 and hence to estimate their local ozone depletion potentials in this region. It is shown that these HCFCs are much less efficiently dissociated within the stratosphere than CFC-11, lowering their ozone depletion potentials to only about 30-40 percent of their chlorine loading potentials. In contrast, the observations of CH3Br and the Halons considered confirm that they are rapidly dissociated within the stratosphere, with important implications for their ozone depletion potentials.

Published
1992

7. BrO and inferred Bry profiles over the western Pacific: Relevance of inorganic bromine sources and a Bry minimum in the aged tropical tropopause layer

Author

Koenig, T.K., Volkamer, R., Baidar, S., Dix, B., Wang, Shanshan, Anderson, D.C., Salawitch, R.J., Wales, P.A., Cuevas, Carlos A., Fernández, Rafael P., Saiz-Lopez, A., Evans, M.J., Sherwen, T., Jacob, Daniel J., Schmidt, J., Kinnison, Douglas E., Lamarque, Jean-François, Apel, E.C., Bresch, J.C., Campos, T., Flocke, F.M., Hall, S.R., Honomichl, S.B., Hornbrook, Rebecca S., Jensen, J.B., Lueb, R., Montzka, D.D., Pan, L.L., Michael Reeves, J., Schauffler, S.M., Ullmann, K., Weinheimer, A.J., Atlas, Elliot L., Donets, V., Navarro, M. A., Riemer, D., Blake, N.J., Chen, D., Gregory Huey, L., Tanner, D.J., Hanisco, T.F., Wolfe, G.M., Koenig, T.K., Volkamer, R., Baidar, S., Dix, B., Wang, Shanshan, Anderson, D.C., Salawitch, R.J., Wales, P.A., Cuevas, Carlos A., Fernández, Rafael P., Saiz-Lopez, A., Evans, M.J., Sherwen, T., Jacob, Daniel J., Schmidt, J., Kinnison, Douglas E., Lamarque, Jean-François, Apel, E.C., Bresch, J.C., Campos, T., Flocke, F.M., Hall, S.R., Honomichl, S.B., Hornbrook, Rebecca S., Jensen, J.B., Lueb, R., Montzka, D.D., Pan, L.L., Michael Reeves, J., Schauffler, S.M., Ullmann, K., Weinheimer, A.J., Atlas, Elliot L., Donets, V., Navarro, M. A., Riemer, D., Blake, N.J., Chen, D., Gregory Huey, L., Tanner, D.J., Hanisco, T.F., and Wolfe, G.M.

Abstract

We report measurements of bromine monoxide (BrO) and use an observationally constrained chemical box model to infer total gas-phase inorganic bromine (Br) over the tropical western Pacific Ocean (tWPO) during the CONTRAST field campaign (January-February 2014). The observed BrO and inferred Br profiles peak in the marine boundary layer (MBL), suggesting the need for a bromine source from sea-salt aerosol (SSA), in addition to organic bromine (CBr). Both profiles are found to be C-shaped with local maxima in the upper free troposphere (FT). The median tropospheric BrO vertical column density (VCD) was measured as 1.6×1013 molec cm-2, compared to model predictions of 0.9×1013 molec cm-2 in GEOS-Chem (CBr but no SSA source), 0.4×1013 molec cm-2 in CAM-Chem (CBr and SSA), and 2.1×1013 molec cm-2 in GEOS-Chem (CBr and SSA). Neither global model fully captures the C-shape of the Br profile. A local Br maximum of 3.6 ppt (2.9-4.4 ppt; 95 % confidence interval, CI) is inferred between 9.5 and 13.5 km in air masses influenced by recent convective outflow. Unlike BrO, which increases from the convective tropical tropopause layer (TTL) to the aged TTL, gas-phase Br decreases from the convective TTL to the aged TTL. Analysis of gas-phase Br against multiple tracers (CFC-11, H2O-O3 ratio, and potential temperature) reveals a Br minimum of 2.7 ppt (2.3-3.1 ppt; 95 % CI) in the aged TTL, which agrees closely with a stratospheric injection of 2.6 ± 0.6 ppt of inorganic Br (estimated from CFC-11 correlations), and is remarkably insensitive to assumptions about heterogeneous chemistry. Br increases to 6.3 ppt (5.6-7.0 ppt; 95 % CI) in the stratospheric >middleworld> and 6.9 ppt (6.5-7.3 ppt; 95 % CI) in the stratospheric >overworld>. The local Br minimum in the aged TTL is qualitatively (but not quantitatively) captured by CAM-Chem, and suggests a more complex partitioning of gas-phase and aerosol Br species than previously recognized. Our data provide corroborating evidence that ino

Published
2017

11. Airborne Measurements of Ethene from Industrial Sources Using Laser Photo-Acoustic Spectroscopy

Author

Gouw, J.A. De, Lintel Hekkert, Sacco te, Mellqvist, J., Warneke, C., Atlas, E.L., Fehsenfeld, F.C., Fried, A., Frost, G.J., Harren, F.J.M., Holloway, J.S., Lefer, B., Lueb, R., Meagher, J.F., Parrish, D.D., Patel, M., Pope, L., Richter, D., Rivera, C., Ryerson, T.B., Samuelsson, J., Walega, J., Washenfelder, R.A., Weibring, P., Zhu, X., Gouw, J.A. De, Lintel Hekkert, Sacco te, Mellqvist, J., Warneke, C., Atlas, E.L., Fehsenfeld, F.C., Fried, A., Frost, G.J., Harren, F.J.M., Holloway, J.S., Lefer, B., Lueb, R., Meagher, J.F., Parrish, D.D., Patel, M., Pope, L., Richter, D., Rivera, C., Ryerson, T.B., Samuelsson, J., Walega, J., Washenfelder, R.A., Weibring, P., and Zhu, X.

Abstract

Contains fulltext : 75227pub.pdf (publisher's version ) (Closed access)

Published
2009

12. Airborne and ground-based observations of a weekend effect in ozone, precursors, and oxidation products in the California South Coast Air Basin

Author

Pollack, I. B., primary, Ryerson, T. B., additional, Trainer, M., additional, Parrish, D. D., additional, Andrews, A. E., additional, Atlas, E. L., additional, Blake, D. R., additional, Brown, S. S., additional, Commane, R., additional, Daube, B. C., additional, de Gouw, J. A., additional, Dubé, W. P., additional, Flynn, J., additional, Frost, G. J., additional, Gilman, J. B., additional, Grossberg, N., additional, Holloway, J. S., additional, Kofler, J., additional, Kort, E. A., additional, Kuster, W. C., additional, Lang, P. M., additional, Lefer, B., additional, Lueb, R. A., additional, Neuman, J. A., additional, Nowak, J. B., additional, Novelli, P. C., additional, Peischl, J., additional, Perring, A. E., additional, Roberts, J. M., additional, Santoni, G., additional, Schwarz, J. P., additional, Spackman, J. R., additional, Wagner, N. L., additional, Warneke, C., additional, Washenfelder, R. A., additional, Wofsy, S. C., additional, and Xiang, B., additional

Published
2012
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13. Atmospheric emissions from the Deepwater Horizon spill constrain air-water partitioning, hydrocarbon fate, and leak rate

Author

Ryerson, T. B., primary, Aikin, K. C., additional, Angevine, W. M., additional, Atlas, E. L., additional, Blake, D. R., additional, Brock, C. A., additional, Fehsenfeld, F. C., additional, Gao, R.-S., additional, de Gouw, J. A., additional, Fahey, D. W., additional, Holloway, J. S., additional, Lack, D. A., additional, Lueb, R. A., additional, Meinardi, S., additional, Middlebrook, A. M., additional, Murphy, D. M., additional, Neuman, J. A., additional, Nowak, J. B., additional, Parrish, D. D., additional, Peischl, J., additional, Perring, A. E., additional, Pollack, I. B., additional, Ravishankara, A. R., additional, Roberts, J. M., additional, Schwarz, J. P., additional, Spackman, J. R., additional, Stark, H., additional, Warneke, C., additional, and Watts, L. A., additional

Published
2011
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14. Airborne Measurements of Ethene from Industrial Sources Using Laser Photo-Acoustic Spectroscopy

Author

de Gouw, J. A., primary, Te Lintel Hekkert, S., additional, Mellqvist, J., additional, Warneke, C., additional, Atlas, E. L., additional, Fehsenfeld, F. C., additional, Fried, A., additional, Frost, G. J., additional, Harren, F. J. M., additional, Holloway, J. S., additional, Lefer, B., additional, Lueb, R., additional, Meagher, J. F., additional, Parrish, D. D., additional, Patel, M., additional, Pope, L., additional, Richter, D., additional, Rivera, C., additional, Ryerson, T. B., additional, Samuelsson, J., additional, Walega, J., additional, Washenfelder, R. A., additional, Weibring, P., additional, and Zhu, X., additional

Published
2009
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15. Trace gases in the Antarctic Atmosphere

Author

Heidt, L. E, Pollock, W. H, Lueb, R. A, Henry, B. E, and Vedder, J. F

Subjects
Geophysics
Abstract

Whole-air samples collected aboard the NASA ER-2 and DC-8 aircraft as part of the Airborne Antarctic Ozone Experiment were analyzed in a field laboratory set up at Punta Arenas, Chile. Mixing ratios obtained from gas chromatographic analyses of these samples are presented for CH4, CO, N2O, CFCl3, CF2Cl2, C2F3Cl3, CH3CCl3, and CCl4. A comparison of CFCl3/N2O mixing ratios from the flights of September 16-29, 1987 provides evidence of sustained subsidence.

Published
1989

16. Concentrations of CH4, CO, CO2, H2, H2O and N2O in the upper stratosphere

Author

Ehhalt, D. H, Heidt, L. E, Lueb, R. H, and Martell, E. A

Subjects
Geophysics
Abstract

On 23 May 1973 a cryogenic air sampler was flown on an Aerobee rocket from White Sands Missile Range. A large air sample was collected between 40 and 50 km altitude and successfully recovered for water vapor and trace gas analysis. The results were as follows: water vapor, 4.0 (+1.3 or - 0.9) ppmV; methane, 0.37 + or - 0.01 ppmV; molecular hydrogen, 0.47 + or - 0.02 ppmV; carbon monoxide, 0.05 + or - 0.01 ppmV; carbon dioxide, 316.2 + or - 2.8 ppmV; and nitrous oxide, 3 + or - 7 ppb.

Published
1975
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19. An examination of chemistry and transport processes in the tropical lower stratosphere using observations of long-lived and short-lived compounds obtained during STRAT and POLARIS

Author

Flocke, F., primary, Herman, R. L., additional, Salawitch, R. J., additional, Atlas, E., additional, Webster, C. R., additional, Schauffler, S. M., additional, Lueb, R. A., additional, May, R. D., additional, Moyer, E. J., additional, Rosenlof, K. H., additional, Scott, D. C., additional, Blake, D. R., additional, and Bui, T. P., additional

Published
1999
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27. Observations of air composition in Brazil between the Equator and 20 degree S during the dry season

Author

Crutzen, P.J., Coffey, M.T., Delany, A.C., Greenberg, J., Haagenson, P., Heidt, L., Lueb, R., Mankin, W.G., Pollock, W., Seiler, W., Wartburg, A., Zimmermann, P., and Publica

Abstract

Field measurement programs in Brazil during the dry season months of August and September in 1979 and 1980 have demonstrated the great importance of the continental tropics in global air chemistry. Especially in the mixed layer, the air composition over land is much different from that over the ocean and the land areas are clearly large scale sources of many important trace gases. During the dry season much biomass burning takes place especially in the cerrado regions leading to substantial emission of air pollutants, such as CO, NOx, N2O, CH4 and other hydrocarbons. Ozone concentrat ions are also enhanced due to photochemical reactions. Biogenic organic emissions from tropical forests play likewise an important role in the photochemistry of the atmosphere. Carbon monoxide was found to be present in high concentrations in the boundary layer of the tropical forest, but ozone concentrations were much lower than in the cerrado. (IFU)

Published
1985

33. East Asian summer monsoon delivers large abundances of very-short-lived organic chlorine substances to the lower stratosphere.

Author

Pan LL, Atlas EL, Honomichl SB, Smith WP, Kinnison DE, Solomon S, Santee ML, Saiz-Lopez A, Laube JC, Wang B, Ueyama R, Bresch JF, Hornbrook RS, Apel EC, Hills AJ, Treadaway V, Smith K, Schauffler S, Donnelly S, Hendershot R, Lueb R, Campos T, Viciani S, D'Amato F, Bianchini G, Barucci M, Podolske JR, Iraci LT, Gurganus C, Bui P, Dean-Day JM, Millán L, Ryoo JM, Barletta B, Koo JH, Kim J, Liang Q, Randel WJ, Thornberry T, and Newman PA

Abstract

Deep convection in the Asian summer monsoon is a significant transport process for lifting pollutants from the planetary boundary layer to the tropopause level. This process enables efficient injection into the stratosphere of reactive species such as chlorinated very-short-lived substances (Cl-VSLSs) that deplete ozone. Past studies of convective transport associated with the Asian summer monsoon have focused mostly on the south Asian summer monsoon. Airborne observations reported in this work identify the East Asian summer monsoon convection as an effective transport pathway that carried record-breaking levels of ozone-depleting Cl-VSLSs (mean organic chlorine from these VSLSs ~500 ppt) to the base of the stratosphere. These unique observations show total organic chlorine from VSLSs in the lower stratosphere over the Asian monsoon tropopause to be more than twice that previously reported over the tropical tropopause. Considering the recently observed increase in Cl-VSLS emissions and the ongoing strengthening of the East Asian summer monsoon under global warming, our results highlight that a reevaluation of the contribution of Cl-VSLS injection via the Asian monsoon to the total stratospheric chlorine budget is warranted., Competing Interests: Competing interests statement:The authors declare no competing interest.

Published
2024
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