David Fitzjarrald, ASRC Researcher, Receives Department of Energy Grant

David R. Fitzjarrald
Atmospheric Sciences Research Center

Sponsor:     Department of Energy
Dates:         January 1, 2014 – December 31, 2014
Amount:     $127, 491

Bridging Land-Surface Fluxes and Aerosol Concentrations to Triggering Convective Rainfall

The proposed field and numerical studies will provide new data sets and new understanding of organic aerosols influences on cloud formation and rainfall processes. Tethered balloon observations will also provide insights into the distribution of aerosol precursors and aerosols in the atmospheric boundary layer and how these are perturbed by pollution. The generated data sets will permit to determine the influence of anthropogenically influenced secondary organic aerosols in regional climate.

The proposed research explores the life cycle of secondary aerosols in pristine and polluted conditions at the ZF2, T3 and ATTO sites of the GoAmazon2014 project. The investigation spans the biological and physical conditions influencing emissions and reactions of precursors (biogenic and anthropogenic volatile organic compounds, VOCs), formation, transport of aerosols out of the atmospheric boundary layer (ABL) and their role on cloud formation and precipitation triggers. The hypothesis to be evaluated is that in rural environments, secondary organic aerosols principally form as the result of the photo-oxidation of VOCs whereas in polluted environments, aerosols originate from both direct sources and reactions entailing biogenic and anthropogenic VOCs. The outcome of these investigations will be propagated to the larger problem of interaction between land cover and cumulus initiation, with emphasis on how boundary-layer air is injected into the cloud layers. Since aerosols influenced by polluted air masses are more hygroscopic than the ones formed in rural environments, they influence cloud formation processes and rainfall yields.

Field observations are planned at the GOAmazon project sites near Manaus, Amazonas, Brazil during February and September 2014, with data analysis and modeling
work to continue for the following two years.