AGS-PRF: The Effects of Aerosols on Cloud Microphysics and Precipitation in the Caribbean

Hosannah Nathan A, New York NY

Investigators

Abstract

The Caribbean is a tropical coastal region formed of islands and continental coasts of more than 40 million inhabitants and a diverse ecosystem. The key to further understanding the Caribbean water cycle is through investigation of the roles aerosols and clouds play in modulating precipitation. The Caribbean lies in the path of the Saharan dust plume, which is theorized to play a crucial role in impacting the seasonal variability of rainfall. Very little is known about the role of aerosols in controlling climate and weather in tropical locations. It is therefore the main objective of this research to improve our understanding of aerosol particle size distribution (PSD) and source effects on cloud processes and precipitation in tropical coastal environments. The study will include observational analyses of several variables (PSD, precipitation rate, total accumulated rainfall totals, wind, etc.) and how these variables relate to one another. The observational analysis will be complemented by a modeling effort using a cloud resolving model to investigate precipitation patterns under different PSD scenarios. When available, PSD data from NASA's AERONET will be coupled with Ceilometer/LIDAR data in order to attain a 3D PSD signature above the region that will be updated as data is available (4D). This data will be processed and ingested directly into a two moment cloud resolving model (that predicts hydrometeor mass mixing ratios and number concentrations) in order to determine the effects of PSD on precipitation. The next phase of the work is to incorporate aerosol chemistry information into the numerical analysis. Computational products resulting from this work will be available to the scientific community via the Coastal Urban Environmental Research Group (CUERG) computational server, resident at City College of New York (CCNY), which will serve as the host institution. The research will be supervised by Professor Jorge Gonzalez of CCNY's Mechanical Engineering Department, who will serve as the sponsoring scientist. This research will also serve to connect researchers from CCNY with scientists from the University of Puerto Rico (UPR) in an effort to learn about local impacts of aerosol at each of UPR's multiple AERONET sites. Intellectual merit: The research advances the discovery and implementation of Caribbean aerosol PSD signatures in cloud resolving models, while increasing understanding of how aerosol impacts on precipitation over the region. At present, PSD data in the Caribbean is scarce and we hope to fill this scientific and practical gap by combining multiple sources of data into a unique repository which will be made available to the scientific community. The research will include unique high resolution precipitation modeling techniques where PSD data will be ingested into the model for the purpose of improving forecasting of weather events. Broader impacts: Understanding and predicting climate/weather in the Caribbean is an important societal and scientific undertaking. The region is exposed to continental scale aerosol loadings from Saharan dust and biomass burning from the Amazon, which, coupled with the rapid urbanization of the islands, would result in complex aerosol structures that may have a profound impact on climate and weather. The work herein will provide results that can likely improve forecasting of extreme weather events, and spark international dialogue on the subject of the role of aerosols in modulating the Caribbean water cycle. Finally, the research will serve as a training platform for a postdoctoral scholar from an underrepresented group in the scientific community.