Enhancement of the relationship between boreal summer precipitation over eastern China and Australia since the early 1980s

摘要

The relationship between the boreal summer (June-August, JJA) precipitation over eastern China and Australia is investigated in this study. The relationship exhibits a decadal enhancement with correlation coefficients increasing from 0.07 before the early 1980s to 0.60 thereafter. A mechanistic analysis suggests that the variability in sea surface temperature (SST) over the central tropical Pacific could play an important role in enhancing the precipitation relationship between the two regions. Over the past half century, the central Pacific SST has shown a warming trend with a significant decadal change that occurred around the early 1980s. Such changes in the central Pacific SST have resulted in stronger convective activity over the tropics, as well as eastern China and Australia since the early 1980s. In addition, since the early 1980s, the central Pacific SST stimulated anomalous twin anticyclones located on opposite sides of the equator, which changed the transportation of water vapour to eastern China and Australia. These changes in the atmospheric circulation related to central tropical Pacific SST have enhanced the impact on the precipitation variability over eastern China and Australia. Consequently, this has contributed to the covariability in the boreal summer precipitation over the two regions since the early 1980s. The result indicates that concurrent climate anomalies can provide simultaneously occurring natural disasters over Asia and Australia, which creates a challenge for international disaster prevention and mitigation.