Speaker: Aishwarya Raman (NASA, GMAO)
Title: Challenges in developing better observational constraints and models for aerosols: Emerging ideas for design and use of future observing systems

Abstract:
Aerosols are significant to air quality and climate. With the growing need to develop better models and observations for aerosols, Aerosol Optical Depth (AOD) products at high spatial and temporal resolution (e.g., MISR, MAIAC, GOES) are used along with other aerosol extinction properties (e.g., angstrom exponent), ground-based radar and lidar measurements of aerosol-cloud profiles to develop novel observational constraints for aerosol composition. Despite these efforts, large uncertainties still exist in aerosol emissions, distribution, and aerosol-meteorology connection due to insufficient measurements of aerosol composition, related observation errors, and large variability in aerosol parameterizations. This talk will address some key questions : (1) What do we have from the current observational system for aerosol composition? ; What are the challenges, and what do we need?; (2) How can we develop new observational constraints?; (3) How can we combine satellite aerosol retrievals in regional models like WRF-Chem to improve our understanding of aerosol composition and impact of meteorology on aerosols? In this context, I will cover three test cases: 1) Capabilities and challenges involved in modeling and analysis of convective dust storms (haboobs) in the South Western U.S. I will discuss the effectiveness of a synergistic approach that brings together multi-satellite retrievals, dual-pol radar reflectivities, and WRF-Chem model for characterizing dust aerosols from the convective dust storms. I will also briefly discuss the trends in AOD anomalies in this region as seen from satellite retrievals. (2) Utility of passive microwave retrievals of whitecap in developing a wind and wave-based parameterizations for oceanic whitecap. I will discuss the implementation of a wave model in GEOS and how wave properties can be useful to improve oceanic whitecap and sea salt aerosols. (3) Finally, I will also discuss a novel method to improve the AOD forecasts across Continental United States using MODIS AOD retrievals and WRF-Chem forecasts in an Analog Ensemble Kalman Filter Framework.