Sensitivity of the summer precipitation to tropical sea surface temperature over East Asia

In this study, uncoupled atmospheric general circulation model experiments are conducted to examine a sensitivity of tropical Ocean basins from the Indian Ocean to the tropical Pacific Ocean on the precipitation variability over East Asia. It is remarkable that the Indian Ocean basin sea surface temperature (SST) and the tropical Pacific basin SST differently act to the precipitation variability over Northeast Asia (110-145°E, 30-45°N) and southern China (100-120°E, 20-30°N). That is, the warming of Indian Ocean SST largely contributes to increase the amount of precipitation over East Asia, which is in contrast to the warming of western tropical Pacific Ocean. Therefore, a gradual warming of both the Indian Ocean and the western tropical Pacific Ocean during recent decades plays a role to reduce the precipitation variability in association with East Asian summer monsoon. On the other hand, a linear relationship between the Northeast Asian precipitation and the tropical basin SSTs decreases when the location of Ocean basin is shifted from the west to the east. Our further analysis indicates that a difference of large-scale atmospheric circulation over the western tropical Pacific is important to lead a contrast of atmospheric motion over East Asia through the tropics-East Asia teleconnections, which results in differing the precipitation variability due to the warming of Indian Ocean and western tropical Pacific Ocean.