Is there a persistent control of monsoon winds by precipitation during the late Holocene?

Abstract

Past variations in the south Asian summer monsoon (Southwest Monsoon, SWM) have been inferred earlier mainly using wind proxies in marine sediment cores from the upwelling-dominated western Arabian Sea. Here we report precipitation proxies, i.e., high-resolution stable oxygen isotope variations, of two different species of planktonic foraminifera, namely, Gs. sacculifer and Gs. ruber, in an AMS 14C dated sediment core from the monsoon-runoff-dominated eastern Arabian Sea. The above data sets reveal that during the past -1800 years (and perhaps up to -2800 years; resolution of the wind record is too low for comparison) reductions in monsoon wind strength in the western Arabian Sea appear to be persistently accompanied by aridity over India. It clarifies that past fluctuations in SWM precipitation over the Indian subcontinent followed the wind intensity records from the western Arabian Sea on centennial time scales. We further provide the first paleoclimatic evidence for the control exerted by SWM precipitation over the SWM wind strength via latent heat release.© Copyright 2006 by the American Geophysical Union.