Summertime Arctic Aerosol Optical Depth Climatology and Trend Derived from Remote Sensing Retrievals, Aerosol Reanalyses and Ground Observations

Abstract:

In this study, three aerosol reanalysis products, including Navy Aerosol Analysis and Prediction System (NAAPS) Aerosol Optical Depth (AOD) reanalysis, NASA Modern-Era Retrospective analysis for Research and Applications, Version-2 (MERRA-2) and ECMWF Copernicus Atmosphere Monitoring Service reanalysis (CAMSRA), and aerosol retrieval products from MISR, CALIOP, and OMI are combined with ground-based AERONET observations to study the spatial and temporal distributions of summertime Arctic aerosols and its trend over the Arctic for the past two decades. Anthropogenic pollution and biomass burning smoke mostly transported from lower latitudes, marine aerosols released locally, and dust emitted from bare land due to glacier retreat are from time to time observed over the Arctic. These aerosols can exert significant influence on polar atmospheric processes, including but not limited to aerosol-climate direct and indirect radiative feedbacks, surface deposition and the “browning” of ice and snow, and chemical processing mechanisms. Quantification of the Arctic aerosol amount and its trend is important for estimating aerosols’ climate impact over the Arctic. The result would facilitate the Arctic research community to evaluate direct and indirect smoke aerosol climate effects.