Solar control of southwest monsoon on centennial timescales

摘要

Solar forcing is proposed to be a major governing factor for the southwest monsoon (SWM) strength during the Holocene. The southeastern Arabian Sea is significantly affected by monsoon run-off and is an ideal testing ground. Stable oxygen isotopic composition ( delta super(18)O) of three species of planktonic foraminifera (Globigerinoides ruber, Gs. sacculifer and Globarotalia menardii) with high time-resolution ( similar to 50 yrs) in a sediment core raised from the region is analysed, and documented past variations in SWM precipitation. High-resolution isotopic and spectral analyses show that solar forcing indeed played a major role in governing the past variations in SWM precipitation on centennial timescales.