Variability of the low-level cross-equatorial jet of the western Indian Ocean since 1660 as derived from coral proxies

Abstract

Using monthly-seasonally resolved coral proxies from the Indian Ocean basin, we statistically reconstruct the June-July-August (JJA) low-level jet in western Indian Ocean from 1660-1957 with skillful estimates for high-and low-frequencies. The El Niño/Southern Oscillation (ENSO) signals are reasonably captured. The strength of the jet significantly increases from the late 17th century to late 19th century. The decreasing in reconstructed jet in 20th century disagrees with previous studies which indicated an enhancement of Southern Asian summer monsoon (SASM) in association with the rapid global warming. The jet reconstructions are useful for understanding of SASM variability and the validation of historical monsoon simulation. Copyright 2008 by the American Geophysical Union.