A Persistent Coast Mode of Precipitation in Southeast China Over the Last Millennium

Abstract

Instrumental data set have revealed several summer precipitation patterns in eastern China, being summarized as “tripole,” “dipole” and “coast” modes. The former two have been found to persist at different time scales, leaving the latter unclear in geological records. Here we present 1300‐year hydroclimate records in a tropical maar lake in the southern coast of China using archeal lipid GDGTs, which can reflect lower water redox conditions largely regulated by lake water depth. The down‐core GDGTs reveal a relatively drier condition during the medieval climate anomaly compared to the Little Ice Age, in‐phase with other records in southeast coast of China but opposite to the inland region, hence demonstrating a persistent “coast” mode in eastern China. The thermal state of equatorial Pacific is suggested to play an important role in shaping the “coast” mode by modulating the location and strength of the western Pacific subtropical high and tropical typhoons.