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Published April 27, 2016 | Published + Supplemental Material
Journal Article Open

Wet scavenging of soluble gases in DC3 deep convective storms using WRF-Chem simulations and aircraft observations

Abstract

We examine wet scavenging of soluble trace gases in storms observed during the Deep Convective Clouds and Chemistry (DC3) field campaign. We conduct high-resolution simulations with the Weather Research and Forecasting model with Chemistry (WRF-Chem) of a severe storm in Oklahoma. The model represents well the storm location, size, and structure as compared with Next Generation Weather Radar reflectivity, and simulated CO transport is consistent with aircraft observations. Scavenging efficiencies (SEs) between inflow and outflow of soluble species are calculated from aircraft measurements and model simulations. Using a simple wet scavenging scheme, we simulate the SE of each soluble species within the error bars of the observations. The simulated SEs of all species except nitric acid (HNO_3) are highly sensitive to the values specified for the fractions retained in ice when cloud water freezes. To reproduce the observations, we must assume zero ice retention for formaldehyde (CH_2O) and hydrogen peroxide (H_2O_2) and complete retention for methyl hydrogen peroxide (CH_3OOH) and sulfur dioxide (SO_2), likely to compensate for the lack of aqueous chemistry in the model. We then compare scavenging efficiencies among storms that formed in Alabama and northeast Colorado and the Oklahoma storm. Significant differences in SEs are seen among storms and species. More scavenging of HNO_3 and less removal of CH_3OOH are seen in storms with higher maximum flash rates, an indication of more graupel mass. Graupel is associated with mixed-phase scavenging and lightning production of nitrogen oxides (NO_x), processes that may explain the observed differences in HNO_3 and CH_3OOH scavenging.

Additional Information

© 2016 American Geophysical Union. Received 8 DEC 2015; Accepted 26 MAR 2016; Accepted article online 2 APR 2016; Published online 21 APR 2016. We express our appreciation to the following researchers for the aircraft observations: T. Ryerson and the NOAA NO_yO_3 team; Andrew Weinheimer; Mark Zondlo, Josh DiGangi, and Anthony O'Brien for the VCSEL hygrometer water vapor measurements on the GV; and P. Lawson and S. Woods from SPEC Inc. We also thank A. Weinheimer and M. Zondlo for their helpful feedback on this manuscript. M.M. Bela and O.B. Toon were supported by NASA ACCDAM-NNX14AR56G. The National Center for Atmospheric Research is sponsored by the National Science Foundation. A. Fried was supported by NSF and NASA under grants AGS-1261559 and NNX12AMO8G, respectively. C. Homeyer was funded by NSF grant AGS-1522910. The University of Maryland co-authors were supported under NSF grants 1063479 and 1522551. Q. Yang was supported by the Office of Science of the U.S. Department of Energy as part of the Atmospheric System Research Program (ASR). P.O. Wennberg, J.D. Crounse, A.P. Teng, and J.M. St. Clair thank NASA for supporting their contribution to this study (NNX12AC06G and NNX14AP46G-ACCDAM). D. O'Sullivan thanks NSF for support from grant ATM1063467. L.G. Huey, D. Chen, and X. Liu were funded by NASA grant NNX12AB77G. DC3 measurements by N. Blake and D. Blake were supported by NASA award NNX12AB76G. We would like to thank Earth Networks for providing the ENTLN lightning data for research purposes. The data used in this study can be downloaded from the following websites: 1 s data merges from the NASA Langley DC3 Merged Aircraft Dataset Archive (http://www-air.larc.nasa.gov/cgi-bin/ArcView/dc3); NEXRAD data for individual radars from the National Climatic Data Center (NCDC; http://has.ncdc.noaa.gov/pls/plhas/has.dsselect); NSSL-MGAUS sounding data (http://data.eol.ucar.edu/codiac/dss/id=353.105); NCEP Stage IV precipitation analysis (http://www.emc.ncep.noaa.gov/mmb/ylin/pcpanl/stage4/); and NAM-ANL (http://nomads.ncdc.noaa.gov/data/namanl/). The WRF-Chem code and land surface data are available for download from NCAR/MMM (http://www.mmm.ucar.edu/wrf/users/download/get_sources_wps_geog.html). WRF-Chem model output is available upon request to M.M. Bela (megan.bela@colorado.edu).

Attached Files

Published - Bela_et_al-2016-Journal_of_Geophysical_Research__Atmospheres.pdf

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Supplemental Material - jgrd52886-sup-0009-supinfo.tex

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Created:
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Modified:
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