Currently, it is generally believed that the evolution of Indian monsoon is mainly influenced by the orbital-scale summer solar radiation in the northern hemisphere and the centennial-scale North Atlantic climate fluctuation. Recent researches show that the Indian Ocean sea surface temperature change also plays an important role in the millennial-scale monsoon fluctuation during the deglacial period. However, during the interglacial period (for example, the Holocene), the influence of sea surface temperature on monsoon precipitation and land hydrological climate remains to be confirmed.

Recently, Zhang Enlou, a researcher of the Lake Sedimentation and Environmental Evolution Laboratory of Nanjing Institute of Geography & Limnology of Chinese Academy of Sciences, and his partners study the sedimentation records of Yunnan Tengchong and Qinghai since the Last Glacial Maximum, analyze a series of paleoenvironmental characteristics proxies of sediment core on the basis of research on precise dating and systematic lake modern process, and reveal the hydro-climate fluctuation and its driving mechanism, especially in the Holocene study area, since the Last Deglacial period. The research results show that there is also large millennial-scale hydro-climate fluctuation in the southwest monsoon region since the Holocene, especially during the period of ~5000-4000 years. The record is synonymous with the Andaman Sea hydrological record, which indicates that the monsoon precipitation and the resulting river flow change affect the sea surface salinity. These fluctuations are related to the change of sea surface temperature in the tropical Indian Ocean in the monsoon source region and the sea surface temperature is an important factor to control the change of water vapor in the monsoon source region. The higher the sea surface temperature is, the stronger the evaporation of seawater will be, and the more the monsoon precipitation will be. Therefore, the solar radiation and the sea surface temperature in the tropical Indian Ocean are consistent from the Last Deglacial period to the Holocene.

Recently, the research achievements were published in Geology, a famous international journal of geosciences (Zhang E., Zhao C., Xue B., Liu Z., Yu Z., Chen R., and Shen J.. Millennial-scale hydroclimate variations in southwest China linked to tropical Indian Ocean since the Last Glacial Maximum. Geology, 2017, 45(5): 435-438).