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Wet scavenging of soluble gases in DC3 deep convective storms using WRF‐Chem simulations and aircraft observations
Author(s) -
Bela Megan M.,
Barth Mary C.,
Toon Owen B.,
Fried Alan,
Homeyer Cameron R.,
Morrison Hugh,
Cummings Kristin A.,
Li Yunyao,
Pickering Kenneth E.,
Allen Dale J.,
Yang Qing,
Wennberg Paul O.,
Crounse John D.,
St. Clair Jason M.,
Teng Alex P.,
O'Sullivan Daniel,
Huey L. Gregory,
Chen Dexian,
Liu Xiaoxi,
Blake Donald R.,
Blake Nicola J.,
Apel Eric C.,
Hornbrook Rebecca S.,
Flocke Frank,
Campos Teresa,
Diskin Glenn
Publication year - 2016
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2015jd024623
Subject(s) - scavenging , graupel , storm , chemistry , convective storm detection , lightning (connector) , atmospheric sciences , outflow , nitric acid , meteorology , environmental science , convection , geology , physics , inorganic chemistry , thermodynamics , biochemistry , power (physics) , antioxidant
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 2 O) and hydrogen peroxide (H 2 O 2 ) and complete retention for methyl hydrogen peroxide (CH 3 OOH) 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 3 OOH 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 3 OOH scavenging.