Modeling the aerosol chemical composition of the tropopause over the Tibetan Plateau during the Asian summer monsoon

作者：Jianzhong Ma, Christoph Brühl, Qianshan He, B. Steil, Vlassis A. Karydis, Klaus Klingmüller, Holger Tost, Бин Чэн, Yufang Jin, Ningwei Liu, Xiangde Xu, Yan Peng, Xiuji Zhou, Kamal Abdelrahman, Andrea Pozzer, Jos Lelieveld · 发表于：Atmospheric chemistry and physics · 年份：2019 · DOI：10.5194/acp-19-11587-2019 · 被引用次数：61 · 研究领域：Atmospheric Ozone and Climate、Atmospheric chemistry and aerosols、Atmospheric and Environmental Gas Dynamics

Abstract. Enhanced aerosol abundance in the upper troposphere and lower stratosphere (UTLS) associated with the Asian summer monsoon (ASM) is referred to as the Asian Tropopause Aerosol Layer (ATAL). The chemical composition, microphysical properties, and climate effects of aerosols in the ATAL have been the subject of discussion over the past decade. In this work, we use the ECHAM/MESSy Atmospheric Chemistry (EMAC) general circulation model at a relatively fine grid resolution (about 1.1×1.1∘) to numerically simulate the emissions, chemistry, and transport of aerosols and their precursors in the UTLS within the ASM anticyclone during the years 2010–2012. We find a pronounced maximum of aerosol extinction in the UTLS over the Tibetan Plateau, which to a large extent is caused by mineral dust emitted from the northern Tibetan Plateau and slope areas, lofted to an altitude of at least 10 km, and accumulating within the anticyclonic circulation. We also find that the emissions and convection of ammonia in the central main body of the Tibetan Plateau make a great contribution to the enhancement of gas-phase NH3 in the UTLS over the Tibetan Plateau and ASM anticyclone region. Our simulations show that mineral dust, water-soluble compounds, such as nitrate and sulfate, and associated liquid water dominate aerosol extinction in the UTLS within the ASM anticyclone. Due to shielding of high background sulfate concentrations outside the anticyclone from volcanoes, a relative minimum of...