AOSC Seminar by Dr. Mary Barth, 9/28/2023
AOSC Seminar
Dr. Mary Barth
NCAR
Title:
Vertical Transport of Aerosols and Trace Gases in Deep Convection
Abstract:
Convective storms over the central U.S. are often an everyday occurrence during the late spring and summer and have a significant impact on upper troposphere composition affecting water vapor, ozone, and aerosols; constituents that affect the radiative forcing of the climate system. Two important processes in deep convection are vertical transport and removal of constituents by microphysical scavenging. We have calculated scavenging efficiencies of aerosol mass concentrations and soluble trace gases based on observations from the Deep Convective Clouds and Chemistry (DC3) and the Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field experiments combined with process scale modeling. In general, scavenging efficiencies do not change substantially in different types of storms. Key ozone precursors, hydrogen peroxide and formaldehyde, have scavenging efficiencies of >80% and ~50%, while methyl hydroperoxide scavenging efficiencies vary over a wide range and are often greater than that expected by Henry’s Law equilibrium. While sulfate, ammonium, and organic aerosols had ~80% or greater scavenging efficiencies, aerosol nitrate scavenging efficiencies were often smaller. Further analysis shows the role of entrainment and lightning-production of nitrogen oxides in affecting the aerosol nitrate redistribution. These results highlight the complex interactions between dynamics, physics, and chemistry in thunderstorms that all need to be represented well in chemistry transport models.
Bio:
Dr. Mary Barth is a Senior Scientist at NCAR conducting research focused on the interactions between clouds and chemistry. She is using cloud-scale and regional-scale modeling and observations from field experiments to investigate effects of vertical transport, wet scavenging, aqueous-phase chemistry, and lightning in clouds on ozone precursors and aerosol concentrations. She is leading the NCAR System for Integrated Modeling of the Atmosphere (SIMA) cross-disciplinary project to develop a single global-to-local modeling system for addressing a variety of science questions, such as the impact of local convection on the larger scale composition of the upper troposphere. Barth is currently the President of the International Commission on Atmospheric Chemistry and Global Pollution. In 2017 she became a Fellow of the American Meteorological Society.
Contact: Ken Pickering
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AOSC Seminar
Pre-seminar refreshment: N/A
Seminar: 3:30-4:30pm, Room: ATL 2400(only when in-person)
Meet-the-Speaker: 4:30-5:00pm, Room: ATL 3400(only when in-person) [For AOSC Students only]
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