Article

Climate Dynamics

, Volume 36, Issue 9, pp 1633-1647

Simulation of the anthropogenic aerosols over South Asia and their effects on Indian summer monsoon

  • Zhenming JiAffiliated withKey Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of SciencesNational Climate CenterGraduate University of Chinese Academy of Sciences
  • , Shichang KangAffiliated withKey Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of SciencesState Key Laboratory of Cryospheric Science, Chinese Academy of Sciences Email author 
  • , Dongfeng ZhangAffiliated withShanxi Meteorological Bureau
  • , Chunzi ZhuAffiliated withCollege of Atmospheric Science, Nanjing University of Information Science Technology
  • , Jia WuAffiliated withNational Climate Center
  • , Ying XuAffiliated withNational Climate Center

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Abstract

A regional climate model coupled with a chemistry-aerosol model is employed to simulate the anthropogenic aerosols including sulfate, black carbon and organic carbon and their direct effect on climate over South Asia. The model is driven by the NCAR/NCEP re-analysis data. Multi-year simulations with half, normal and double emission fluxes are conducted. Results show that the model performs well in reproducing present climate over the region. Simulations of the aerosol optical depth and surface concentration of aerosols are also reasonable although to a less extent. The negative radiative forcing is found at the top of atmosphere and largely depended on emission concentration. Surface air temperature decreases by 0.1–0.5°C both in pre-monsoon and monsoon seasons. The range and intensity of cooling areas enlarge while aerosol emission increases. Changes in precipitation are between −25 and 25%. Different diversifications of rainfall are showed with three emission scenarios. The changes of precipitation are consistent with varieties of monsoon onset dates in pre-monsoon season. In the regions of increasing precipitation, monsoon onset is advanced and vice versa. In northeast India and Myanmar, aerosols lead the India summer monsoon onset advancing 1–2 pentads, and delaying by 1–2 pentads in central and southeast India. These changes are mainly caused by the anomaly of local Hadley circulations and enhancive precipitation. Tibetan Plateau played a crucial role in the circulation changes.

Keywords

Indian summer monsoon Regional climate model Aerosols Climate effect