Monopole Mode of Precipitation in East Asia Modulated by the South China Sea Over the Last Four Centuries

Shi, Feng [Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, China] Goosse, Hugues [UCL] Klein, François [UCL] Zhao, Sen [CIC‐FEMD/ILCEC, Key Laboratory of Meteorological Disaster of Ministry of Education, College of Atmospheric Sciences, Nanjing University of Information Science and Technology, Nanjing, China] Liu, Ting [State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China] Guo, Zhengtang [Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, China]

Precipitation in East Asia affects one quarter of the global population. However, the mechanisms governing precipitation changes at the century scale remain unclear. Reconstructions of warm season precipitation over the last 531 years show that the dominant mode of variability is a monopole covering most of China. However, this mode is mostly absent from Coupled Model Intercomparison Project Phase 5 results. In contrast, experiments using data assimilation reproduce this monopole mode well. Results show that sea surface temperature in the South China Sea is a major driver of the monopole mode of precipitation via a Gill‐type response. Warm sea surface temperatures induce a distinct baroclinic structure over the central part of eastern China comprising a low‐pressure cyclone in the lower troposphere and a high‐pressure anticyclone in the upper troposphere with rising airflow, resulting in water vapor convergence and increased precipitation in East Asia.