Total Deposition (TDep) Science Committee

2026 Webinar Series Presents:

Modeling ammonia deposition to sensitive ecosystems: resolution, atmospheric lifetime and bidirectional exchange

RECORDED ON MARCH 3, 2026

AGENDA

Presentation:
Modeling ammonia deposition to sensitive ecosystems: resolution, atmospheric lifetime and bidirectional exchange

Summary: The emissions and fate of ammonia are heterogeneous and can be separated by distances as small as tens to hundreds of meters. Additionally, ammonia is semi-volatile and often exhibits bidirectional exchange depending on the ammonium enrichment of the surface. Here, we will discuss model parametrizations of emissions and the fate of ammonia near emission sources with an emphasis on its atmospheric lifetime and bidirectional exchange.

Presented by:
Dr. Jesse Bash – Norwegian Meteorological Institute

Dr. Jesse Bash is a researcher at the Norwegian Meteorological Institute were he develops biogenic emission and dry deposition parametrizations for the European Monitoring and Evaluation Programme (EMEP) Meteorological Synthesizing Centre-West (MSC-W) chemical transport model. Dr. Bash obtained his Ph.D. at the University of Connecticut where he developed a relaxed eddy accumulation system to measure terrestrial total mercury fluxes. Dr. Bash has worked at the National Oceanic and Atmospheric Administration and the U.S. Environmental Protection Agency where developed mercury and ammonia bidirectional exchange models for the Community Multiscale Air Quality (CMAQ) model. His research interests lie in the development of mechanistic models to connect land use change with the sources, fate, biogeochemical feedbacks, and ecosystem exposure of atmospheric pollutants.

Next webinar:

Amy Christiansen
Thursday April 30, 2026 @ 11:00 ET
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Questions?

For further information contact Kristen Foley at foley.kristen@epa.gov