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37 results on '"Schauffler, S. M."'

1. Hydrogen Radicals, Nitrogen Radicals, and the Production of O$_3$ in the Upper Troposphere

Author

Wennberg, P. O., Hanisco, T. F., Jaeglé, L., Jacob, D. J., Hintsa, E. J., Lanzendorf, E. J., Anderson, J. G., Keim, E. R., Donnelly, S. G., Del Negro, L. A., Fahey, D. W., McKeen, S. A., Salawitch, R. J., Webster, C. R., May, R. D., Herman, R. L., Proffitt, M. H., Margitan, J. J., Atlas, E. L., Schauffler, S. M., Flocke, F., McElroy, C. T., and Bui, T. P.

Published
1998

2. Novel approaches to improve estimates of short-lived halocarbon emissions during summer from the Southern Ocean using airborne observations

Author

National Science Foundation (US), National Aeronautics and Space Administration (US), SCOAP, Asher, E., Hornbrook, Rebecca S., Stephens, B. B., Kinnison, Douglas E., Morgan, E. J., Keeling, R. F., Atlas, Elliot L., Schauffler, S. M., Tilmes, S., Kort, E. A., Hoecker-Martínez, M. S., Long, M .C., Lamarque, Jean-François, Saiz-Lopez, A., McKain, K., Sweeney, C., Hills, Alan J., Apel, E.C., National Science Foundation (US), National Aeronautics and Space Administration (US), SCOAP, Asher, E., Hornbrook, Rebecca S., Stephens, B. B., Kinnison, Douglas E., Morgan, E. J., Keeling, R. F., Atlas, Elliot L., Schauffler, S. M., Tilmes, S., Kort, E. A., Hoecker-Martínez, M. S., Long, M .C., Lamarque, Jean-François, Saiz-Lopez, A., McKain, K., Sweeney, C., Hills, Alan J., and Apel, E.C.

Abstract

Fluxes of halogenated volatile organic compounds (VOCs) over the Southern Ocean remain poorly understood, and few atmospheric measurements exist to constrain modeled emissions of these compounds. We present observations of CHBr, CHBr, CHI, CHClBr, CHBrCl, and CHBr during the O2=N Ratio and CO Airborne Southern Ocean (ORCAS) study and the second Atmospheric Tomography mission (ATom-2) in January and February of 2016 and 2017. Good model-measurement correlations were obtained between these observations and simulations from the Community Earth System Model (CESM) atmospheric component with chemistry (CAM-Chem) for CHBr, CHBr, CHI, and CHClBr but all showed significant differences in model: measurement ratios. The model: measurement comparison for CHBr was satisfactory and for CHBrCl the low levels present precluded us from making a complete assessment. Thereafter, we demonstrate two novel approaches to estimate halogenated VOC fluxes; the first approach takes advantage of the robust relationships that were found between airborne observations of O and CHBr, CHBr, and CHClBr. We use these linear regressions with O and modeled O distributions to infer a biological flux of halogenated VOCs. The second approach uses the Stochastic Time-Inverted Lagrangian Transport (STILT) particle dispersion model to explore the relationships between observed mixing ratios and the product of the upstream surface influence of sea ice, chl a, absorption due to detritus, and downward shortwave radiation at the surface, which in turn relate to various regional hypothesized sources of halogenated VOCs such as marine phytoplankton, phytoplankton in seaice brines, and decomposing organic matter in surface seawater. These relationships can help evaluate the likelihood of particular halogenated VOC sources and in the case of statistically significant correlations, such as was found for CHI, may be used to derive an estimated flux field. Our results are consistent with a biogenic regional source of

Published
2019

3. Stratospheric Injection of Brominated Very Short-Lived Substances: Aircraft Observations in the Western Pacific and Representation in Global Models

Author

National Science Foundation (US), National Aeronautics and Space Administration (US), National Center for Atmospheric Research (US), British Atmospheric Data Centre, Australian Research Council, Australian Antarctic Division, German Climate Computing Center, Federal Ministry of Education and Research (Germany), Wales, P. A., Salawitch, R. J., Nicely, J. M., Anderson, D. C., Canty, T. P., Baidar, S., Dix, B., Koenig, T.K., Volkamer, R., Chen, D., Huey, L.G., Tanner, D. J., Cuevas, Carlos A., Fernández, Rafael P., Kinnison, Douglas E., Lamarque, Jean-François, Saiz-Lopez, A., Atlas, Elliot L., Hall, S.R., Navarro, M. A., Pan, L.L., Schauffler, S. M., Stell, M., Tilmes, S., Ullmann, K., Weinheimer, A. J., Akiyoshi, Hideharu, Chipperfield, M.P., Deushi, Makoto, Dhomse, S. S., Feng, W., Graf, P., Hossaini, R., Jöckel, P., Mancini, E., Michou, M., Morgenstern, O., Oman, L. D., Pitari, G., Plummer, David A., Revell, L. E., Rozanov, E., Saint-Martin, D., Schofield, R., Stenke, A., Stone, K. A., Visioni, D., Yamashita, Y., Zeng, G., National Science Foundation (US), National Aeronautics and Space Administration (US), National Center for Atmospheric Research (US), British Atmospheric Data Centre, Australian Research Council, Australian Antarctic Division, German Climate Computing Center, Federal Ministry of Education and Research (Germany), Wales, P. A., Salawitch, R. J., Nicely, J. M., Anderson, D. C., Canty, T. P., Baidar, S., Dix, B., Koenig, T.K., Volkamer, R., Chen, D., Huey, L.G., Tanner, D. J., Cuevas, Carlos A., Fernández, Rafael P., Kinnison, Douglas E., Lamarque, Jean-François, Saiz-Lopez, A., Atlas, Elliot L., Hall, S.R., Navarro, M. A., Pan, L.L., Schauffler, S. M., Stell, M., Tilmes, S., Ullmann, K., Weinheimer, A. J., Akiyoshi, Hideharu, Chipperfield, M.P., Deushi, Makoto, Dhomse, S. S., Feng, W., Graf, P., Hossaini, R., Jöckel, P., Mancini, E., Michou, M., Morgenstern, O., Oman, L. D., Pitari, G., Plummer, David A., Revell, L. E., Rozanov, E., Saint-Martin, D., Schofield, R., Stenke, A., Stone, K. A., Visioni, D., Yamashita, Y., and Zeng, G.

Abstract

We quantify the stratospheric injection of brominated very short-lived substances (VSLS) based on aircraft observations acquired in winter 2014 above the Tropical Western Pacific during the CONvective TRansport of Active Species in the Tropics (CONTRAST) and the Airborne Tropical TRopopause EXperiment (ATTREX) campaigns. The overall contribution of VSLS to stratospheric bromine was determined to be 5.0 ± 2.1 ppt, in agreement with the 5 ± 3 ppt estimate provided in the 2014 World Meteorological Organization (WMO) Ozone Assessment report (WMO 2014), but with lower uncertainty. Measurements of organic bromine compounds, including VSLS, were analyzed using CFC-11 as a reference stratospheric tracer. From this analysis, 2.9 ± 0.6 ppt of bromine enters the stratosphere via organic source gas injection of VSLS. This value is two times the mean bromine content of VSLS measured at the tropical tropopause, for regions outside of the Tropical Western Pacific, summarized in WMO 2014. A photochemical box model, constrained to CONTRAST observations, was used to estimate inorganic bromine from measurements of BrO collected by two instruments. The analysis indicates that 2.1 ± 2.1 ppt of bromine enters the stratosphere via inorganic product gas injection. We also examine the representation of brominated VSLS within 14 global models that participated in the Chemistry-Climate Model Initiative. The representation of stratospheric bromine in these models generally lies within the range of our empirical estimate. Models that include explicit representations of VSLS compare better with bromine observations in the lower stratosphere than models that utilize longer-lived chemicals as a surrogate for VSLS.

Published
2018

4. In situ measurements of BrO during AASE II

Author

Avallone, L. M, Toohey, D. W, Schauffler, S. M, Pollock, W. H, Heidt, L. E, Atlas, E. L, and Chan, K. R

Subjects
Meteorology And Climatology
Abstract

BrO measured from the NASA ER-2 during Airborne Arctic Stratospheric Expedition (AASE) II exhibited a mean value (for 20-minute averages) of 5.4 +/- 0.3 pptv, with a standard deviation of 3.1 pptv. Ratios of BrO to available inorganic bromine (Br(sub y)) show only slight increases in polar regions relative to midlatitudes. A comparison between observed latitudinal and diurnal variations of this same ratio and that calculated by photochemical models shows reasonable agreement in behavior, but significant discrepancies in magnitude. It is unclear whether this difference is due to errors in measurements, models or both.

Published
1995
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5. Estimates of total organic and inorganic chlorine in the lower stratosphere from in situ and flask measurements during AASE 2

Author

Woodbridge, E. L, Elkins, J. W, Fahey, D. W, Heidt, L. E, Solomon, S, Baring, T. J, Gilpin, T. M, Pollack, W. H, Schauffler, S. M, and Atlas, E. L

Subjects
Environment Pollution
Abstract

Aircraft sampling has provided extensive in situ and flask measurements of organic chlorine species in the lower stratosphere. The recent Airborne Arctic Stratospheric Expedition 2 (AASE 2) included two independent measurements of organic chlorine species using whole air sample and real-time techniques. From the whole air sample measurements we derive directly the burden of total organic chlorine (CCl(y)) in the lower stratosphere. From the more limited real-time measurements we estimate the CCl(y) burden using mixing ratios and growth rates of the principal CCl(y) species in the troposphere in conjunction with results from a two-dimensional photochemical model. Since stratospheric chlorine is tropospheric in origin and tropospheric mixing ratios are increasing, it is necessary to establish the average age of a stratospheric air parcel to assess its total chlorine (Cl(sub Total)) abundance. Total inorganic chlorine (Cl(y)) in the parcel is then estimated by the simple difference, Cl(y) = Cl(sub Total) - CCl(y). The consistency of the results from these two quite different techniques suggests that we can determine the CCl(y) and Cl(y) in the lower stratosphere with confidence. Such estimates of organic and inorganic chlorine are crucial in evaluating the photochemistry controlling chlorine partitioning and hence ozone loss processes in the lower stratosphere.

Published
1995
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6. 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

7. 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, Leub, R. A, and Atlas, E. L

Subjects
Environment Pollution
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 midtroposphere 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

9. Chlorine budget and partitioning during the Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment (SOLVE)

Author

Schauffler, S. M., Schauffler, S. M., Atlas, E. L., Donnelly, S. G., Andrews, A., Montzka, S. A., Elkins, J. W., Hurst, D. F., Romashkin, P. A., Dutton, G. S., Stroud, V., Schauffler, S. M., Schauffler, S. M., Atlas, E. L., Donnelly, S. G., Andrews, A., Montzka, S. A., Elkins, J. W., Hurst, D. F., Romashkin, P. A., Dutton, G. S., and Stroud, V.

Abstract

The amount of chlorine in the stratosphere has a direct influence on the magnitude of chlorine-catalyzed ozone loss. A comprehensive suite of organic source gases of chlorine in the stratosphere was measured during the NASA Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment (SOLVE) campaign in the arctic winter of 2000. Measurements included chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halon 1211, solvents, methyl chloride, N2O, and CH4. Inorganic chlorine contributions from each compound were calculated using the organic chlorine measurements, mean age of air, tropospheric trends, and a method to account for mixing in the stratosphere. Total organic chlorine measured at tropospheric levels of N2O was on the order of 3500 ppt. Total calculated inorganic chlorine at a N2O mixing ratio of 50 ppb (corresponding to a mean age of 5.5 years) was on the order of 3400 ppt. CFCs were the largest contributors to total organic chlorine (55-70%) over the measured N2O range (50-315 ppb), followed by CH3Cl (15%), solvents (5-20%), and HCFCs (5-25%). CH3Cl contribution was consistently about 15% across the organic chlorine range. Contributions to total calculated inorganic chlorine at 50 ppb N2O were 58% from CFCs, 24% from solvents, 16% from CH3Cl, and 2% from HCFCs. Updates to fractional chlorine release values for each compound relative to CFC 11 were calculated from the SOLVE measurements. An average value of 0.58 was calculated for the fractional chlorine release of CFC 11 over the 3-4 year mean age range, which was lower than the previous value of 0.80. The fractional chlorine release values for HCFCs 141b and 142b relative to CFC 11 were significantly lower than previous calculations.

Published
2003

10. Chemical composition of air masses transported from Asia to the U.S. West coast during ITCT 2K2: Fossil fuel combustion versus biomass-burning signatures

Author

de Gouw, J. A., de Gouw, J. A., Cooper, O. R., Warneke, C., Hudson, P. K., Fehsenfeld, F. C., Holloway, J. S., Hübler, G., Nicks, Jr K., Nowak, J. B., Parrish, D. D., Ryerson, T. B., Atlas, E. L., Donnelly, S. G., Schauffler, S. M., Stroud, V., Johnson, K., Carmichael, G. R., Streets, D. G., de Gouw, J. A., de Gouw, J. A., Cooper, O. R., Warneke, C., Hudson, P. K., Fehsenfeld, F. C., Holloway, J. S., Hübler, G., Nicks, Jr K., Nowak, J. B., Parrish, D. D., Ryerson, T. B., Atlas, E. L., Donnelly, S. G., Schauffler, S. M., Stroud, V., Johnson, K., Carmichael, G. R., and Streets, D. G.

Abstract

As part of the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT 2K2), a National Oceanic and Atmospheric Administration (NOAA) WP-3D research aircraft was used to study the long-range transport of Asian air masses toward the west coast of North America. During research flights on 5 and 17 May, strong enhancements of carbon monoxide (CO) and other species were observed in air masses that had been transported from Asia. The hydrocarbon composition of the air masses indicated that the highest CO levels were related to fossil fuel use. During the flights on 5 and 17 May and other days, the levels of several biomass-buming indicators increased with altitude. This was true for acetonitrile (CH3CN), methyl chloride (CH3Cl), the ratio of acetylene (C2H2) to propane (C3H8), and, on May 5, the percentage of particles measured by the particle analysis by laser mass spectrometry (PALMS) instrument that were attributed to biomass burning based on their carbon and potassium content. An ensemble of back-trajectories, calculated from the U.S. west coast over a range of latitudes and altitudes for the entire ITCT 2K2 period, showed that air masses from Southeast Asia and China were generally observed at higher altitudes than air from Japan and Korea. Emission inventories estimate the contribution of biomass burning to the total emissions to be low for Japan and Korea, higher for China, and the highest for Southeast Asia. Combined with the origin of the air masses versus altitude, this qualitatively explains the increase with altitude, averaged over the whole ITCT 2K2 period, of the different biomass-burning indicators. Copyright 2004 by the American Geophysical Union.

Published
2004

11. Characterization of NOx, SO2, ethene, and propene from industrial emission sources in Houston, Texas

Author

Washenfelder, R. A., primary, Trainer, M., additional, Frost, G. J., additional, Ryerson, T. B., additional, Atlas, E. L., additional, de Gouw, J. A., additional, Flocke, F. M., additional, Fried, A., additional, Holloway, J. S., additional, Parrish, D. D., additional, Peischl, J., additional, Richter, D., additional, Schauffler, S. M., additional, Walega, J. G., additional, Warneke, C., additional, Weibring, P., additional, and Zheng, W., additional

Published
2010
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14. Chemical composition of air masses transported from Asia to the U.S. West Coast during ITCT 2K2: Fossil fuel combustion versus biomass‐burning signatures

Author

de Gouw, J. A., primary, Cooper, O. R., additional, Warneke, C., additional, Hudson, P. K., additional, Fehsenfeld, F. C., additional, Holloway, J. S., additional, Hübler, G., additional, Nicks Jr., D. K., additional, Nowak, J. B., additional, Parrish, D. D., additional, Ryerson, T. B., additional, Atlas, E. L., additional, Donnelly, S. G., additional, Schauffler, S. M., additional, Stroud, V., additional, Johnson, K., additional, Carmichael, G. R., additional, and Streets, D. G., additional

Published
2004
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18. Observational evidence for the role of denitrification in Arctic stratospheric ozone loss

Author

Gao, R. S., primary, Richard, E. C., additional, Popp, P. J., additional, Toon, G. C., additional, Hurst, D. F., additional, Newman, P. A., additional, Holecek, J. C., additional, Northway, M. J., additional, Fahey, D. W., additional, Danilin, M. Y., additional, Sen, B., additional, Aikin, K., additional, Romashkin, P. A., additional, Elkins, J. W., additional, Webster, C. R., additional, Schauffler, S. M., additional, Greenblatt, J. B., additional, McElroy, C. T., additional, Lait, L. R., additional, Bui, T. P., additional, and Baumgardner, D., additional

Published
2001
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19. Severe and extensive denitrification in the 1999-2000 Arctic winter stratosphere

Author

Popp, P. J., primary, Northway, M. J., additional, Holecek, J. C., additional, Gao, R. S., additional, Fahey, D. W., additional, Elkins, J. W., additional, Hurst, D. F., additional, Romashkin, P. A., additional, Toon, G. C., additional, Sen, B., additional, Schauffler, S. M., additional, Salawitch, R. J., additional, Webster, C. R., additional, Herman, R. L., additional, Jost, H., additional, Bui, T. P., additional, Newman, P. A., additional, and Lait, L. R., additional

Published
2001
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20. 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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21. The budget and partitioning of stratospheric chlorine during the 1997 Arctic summer

Author

Sen, B., primary, Osterman, G. B., additional, Salawitch, R. J., additional, Toon, G. C., additional, Margitan, J. J., additional, Blavier, J.-F., additional, Chang, A. Y., additional, May, R. D., additional, Webster, C. R., additional, Stimpfle, R. M., additional, Bonne, G. P., additional, Voss, P. B., additional, Perkins, K. K., additional, Anderson, J. G., additional, Cohen, R. C., additional, Elkins, J. W., additional, Dutton, G. S., additional, Hurst, D. F., additional, Romashkin, P. A., additional, Atlas, E. L., additional, Schauffler, S. M., additional, and Loewenstein, M., additional

Published
1999
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26. Hydrogen Radicals, Nitrogen Radicals, and the Production of O 3 in the Upper Troposphere

Author

Wennberg, P. O., primary, Hanisco, T. F., additional, Jaeglé, L., additional, Jacob, D. J., additional, Hintsa, E. J., additional, Lanzendorf, E. J., additional, Anderson, J. G., additional, Gao, R.-S., additional, Keim, E. R., additional, Donnelly, S. G., additional, Negro, L. A. Del, additional, Fahey, D. W., additional, McKeen, S. A., additional, Salawitch, R. J., additional, Webster, C. R., additional, May, R. D., additional, Herman, R. L., additional, Proffitt, M. H., additional, Margitan, J. J., additional, Atlas, E. L., additional, Schauffler, S. M., additional, Flocke, F., additional, McElroy, C. T., additional, and Bui, T. P., additional

Published
1998
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27. Distribution of halon-1211 in the upper troposphere and lower stratosphere and the 1994 total bromine budget

Author

Wamsley, P. R., primary, Elkins, J. W., additional, Fahey, D. W., additional, Dutton, G. S., additional, Volk, C. M., additional, Myers, R. C., additional, Montzka, S. A., additional, Butler, J. H., additional, Clarke, A. D., additional, Fraser, P. J., additional, Steele, L. P., additional, Lucarelli, M. P., additional, Atlas, E. L., additional, Schauffler, S. M., additional, Blake, D. R., additional, Rowland, F. S., additional, Sturges, W. T., additional, Lee, J. M., additional, Penkett, S. A., additional, Engel, A., additional, Stimpfle, R. M., additional, Chan, K. R., additional, Weisenstein, D. K., additional, Ko, M. K. W., additional, and Salawitch, R. J., additional

Published
1998
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30. Estimates of total organic and inorganic chlorine in the lower stratosphere from in situ and flask measurements during AASE II

Author

Woodbridge, E. L., primary, Elkins, J. W., additional, Fahey, D. W., additional, Heidt, L. E., additional, Solomon, S., additional, Baring, T. J., additional, Gilpin, T. M., additional, Pollock, W. H., additional, Schauffler, S. M., additional, Atlas, E. L., additional, Loewenstein, M., additional, Podolske, J. R., additional, Webster, C. R., additional, May, R. D., additional, Gilligan, J. M., additional, Montzka, S. A., additional, Boering, K. A., additional, and Salawitch, R. J., additional

Published
1995
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36. Modeling the transport of very short-lived substances into the tropical upper troposphere and lower stratosphere

Author

Aschmann, J., Björn-Martin Sinnhuber, Atlas, E. L., and Schauffler, S. M.

Subjects
lcsh:Chemistry, lcsh:QD1-999, lcsh:Physics, lcsh:QC1-999
Abstract

The transport of very short-lived substances into the tropical upper troposphere and lower stratosphere is investigated by a three-dimensional chemical transport model using archived convective updraft mass fluxes (or detrainment rates) from the European Centre for Medium-Range Weather Forecast's ERA-Interim reanalysis. Large-scale vertical velocities are calculated from diabatic heating rates. With this approach we explicitly model the large scale subsidence in the tropical troposphere with convection taking place in fast and isolated updraft events. The model calculations agree generally well with observations of bromoform and methyl iodide from aircraft campaigns and with ozone and water vapor from sonde and satellite observations. Using a simplified treatment of dehydration and bromine product gas washout we give a range of 1.6 to 3 ppt for the contribution of bromoform to stratospheric bromine, assuming a uniform source in the boundary layer of 1 ppt. We show that the most effective region for VSLS transport into the stratosphere is the West Pacific, accounting for about 55% of the bromine from bromoform transported into the stratosphere under the supposition of a uniformly distributed source.

37. Role of NOyas a diagnostic of small‐scale mixing in a denitrified polar vortex

Author

Gao, R. S., Popp, P. J., Ray, E. A., Rosenlof, K. H., Northway, M. J., Fahey, D. W., Tuck, A. F., Webster, C. R., Hurst, D. F., Schauffler, S. M., Jost, H., and Bui, T. P.

Abstract

Observations of three stratospheric species (N2O, CH4, and NOy) are examined for their suitability as mixing tracers in the inner Arctic vortex region between late February and mid‐March 2000. NOyis highly inhomogeneous on isentropic surfaces and has little systematic vertical gradient between the 420 and 470 K potential temperature surfaces due to severe and extensive denitrification. Probability distribution functions of NOycalculated from in situ measurements do not show systematic and significant change as a function of time, indicating that mixing was too slow to substantially homogenize NOydistribution and therefore to strongly affect photochemical O3destruction rates during the period. We propose that the NOyinhomogeneity is useful for diagnosing small‐scale, irreversible mixing rates during the measurement period. A simple kinematic model is used to show that the NOystandard deviation on an isentropic level in the vortex has desirable properties for quantifying these rates. A practical method for deriving mixing rates for chemistry and transport models has been proposed for future studies.

Published
2002
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