Response of the Asian Summer Monsoon to Weakening of Atlantic Thermohaline Circulation
LU Riyu1,2 and Buwen DONG3,4 1State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 2Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 3Walker Institute for Climate System Research, University of Reading, Reading, UK 4National Centre for Atmospheric Science-Climate, Reading, UK
Various paleoclimate records have shown that the Asian monsoon was punctuated by numerous sub-orbital time-scale events, and these events were coeval with those that happened in the North Atlantic. This study investigates the Asian summer monsoon responses to the Atlantic Ocean forcing by applying an additional freshwater flux into the North Atlantic. The simulated results indicate that the cold North Atlantic and warm South Atlantic induced by the weakened Atlantic thermohaline circulation (THC) due to the freshwater flux lead to significantly suppressed Asian summer monsoon. The authors analyzed the detailed processes of the Atlantic Ocean forcing on the Asian summer monsoon, and found that the atmospheric teleconnection in the eastern and central North Pacific and the atmosphere-ocean interaction in the tropical North Pacific play the most crucial role. Enhanced precipitation in the subtropical North Pacific extends the effects of Atlantic Ocean forcing from the eastern Pacific into the western Pacific, and the atmosphere-ocean interaction in the tropical Pacific and Indian Ocean intensifies the circulation and precipitation anomalies in the Pacific and East Asia.