Abstract:Key Laboratory of Meteorological Disaster, Ministry of Education/ International Joint Laboratory on Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044; CMA Key Laboratory for Climate Prediction Studies, National Climate Centre, Beijing 100081;Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082;CMA Economic Transformation of Climate Resources Key Laboratory, Chongqing Institute of Meteorological Sciences, Chongqing 401147 concerned. However, there are few studies on the relationship and mechanism between the Antarctic Oscillation (AAO) and temperature in summer over the TP. Based on observation and reanalysis data such as CRU monthly temperature, NOAA global monthly sea surface temperature data (ERSSTv5), and AAO index from 1979 to 2020, this paper shows that there is a significant negative correlation between the temperature over the western TP in summer and the AAO in May through linear regression analysis and other methods. That is, when the AAO anomaly is positive in May, the temperature over the western TP in summer is abnormally high. The process of its influence is that when the AAO is in a positive phase, a “negative-positive-negative” meridional “Tripole” sea surface temperature mode appears in the mid to high latitudes of the southern Indian Ocean. This mode can last until summer, inducing the wind anomaly over the Indian Ocean in the zonal and vertical direction. The precipitation anomaly between the tropical western Indian Ocean and the eastern Indian Ocean-Maritime Continent leads to a tropical “Dipole” rainfall mode. As a response, abnormal anticyclone circulation and downward movement appear over the western TP, which is conducive to the high temperature there. The research results in this paper indicate that the thermal inertia of the ocean plays an important role as a bridge in the process of prolonging the influence of the AAO, and it can provide scientific basis for the prediction of summer temperature over the TP.