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Impact of Southeast Asian smoke on aerosol properties in Southwest China: First comparison of model simulations with satellite and ground observations
Journal article   Open access   Peer reviewed

Impact of Southeast Asian smoke on aerosol properties in Southwest China: First comparison of model simulations with satellite and ground observations

Jun Zhu, Xiangao Xia, Jun Wang, Jinqiang Zhang, Christine Wiedinmyer, Jenny A Fisher and Christoph A Keller
Journal of geophysical research. Atmospheres, Vol.122(7), pp.3904-3919
04/16/2017
DOI: 10.1002/2016JD025793
url
https://doi.org/10.1002/2016JD025793View
Published (Version of record) Open Access

Abstract

Smoke aerosols have been observed in Southwest China as a result of long‐range transport from surrounding areas in March and April. The processes driving this transport and the resultant impact on regional aerosol optical properties are studied here through a combined use of the Goddard Earth Observing System (GEOS)‐Chem chemistry transport model in conjunction with satellite and the first‐ever ground‐based observations in the Southwest China. The potential biomass burning source regions as well as their respective contributions to aerosol loading in Southwest China are quantified. Compared to Sun photometer observations of aerosol optical depth (AOD) at 550 nm at eight stations in the study region (10–28°N, 90–115°E, comprising Northeast India, Indo‐China Peninsula, and Southwest and South China), the AOD simulated by GEOS‐Chem (nested grid with 0.5° × 0.667° resolution) by using the Fire Inventory from National Center for Atmospheric Research shows an average bias of −0.17 during January 2012 to May 2013. However, during the biomass burning months (March–April), the simulated AOD is much improved with a bias of −0.04. Model sensitivity experiments show that biomass burning in Burma and Northeast India is the largest contributor to smoke AOD (~88%) and total AOD (~57%) over Kunming, an urban site in Southwest China. Case studies on 21–23 March 2013 show that the smoke layer in Northeast India and North Burma can extend from the surface to 4 km and then be transported to Southwest China by prevailing westerly airflow. Model‐simulated AOD and vertical distribution of aerosols are respectively in good agreement with satellite measurements from Moderate Resolution Imaging Spectroradiometer and Cloud‐Aerosol Lidar with Orthogonal Polarization. Key Points GESO‐Chem model with nested grid capability and FINN emission shows smoke transport from Southeast Asia to Southwest China Simulated AOD temporal variability agrees with that from the limited but first‐ever ground observations in the region Northeast India and Burma are the largest contributor to smoke aerosol in Southwest China
biomass burning Southwest China transport aerosol optical depth

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