Potential of Reef Building Corals to Study the Past Indian Monsoon Rainfall Variability

Reef building corals are known to provide high resolution records of ocean–atmospheric variables for the last several centuries. The most important parameter is the sea surface temperature, which is accurately recorded by the oxygen isotopic composition as well as by a few trace elemental ratios such as, Sr/Ca, Mg/Ca, U/Ca, etc. Determination of the sea surface temperature has enabled the palaeocenographers to study a variety of oceanic processes, such as the El Niño and Southern Oscillation, ocean circulation, air–sea gas exchange, Indian Ocean dipole, etc. Monsoon is an important atmospheric process in which sea surface temperature plays an active role in governing the moisture production and modulation of the wind circulation. Apart from temperature reconstruction, the corals have also been used to study the monsoon processes by some investigators, viz. the estimation of rainfall. In this article, we review the available coral records, specifically for studying the Indian summer monsoon rainfall variability. The study reveals that the coral records only from a few specific regions show promise in this endeavour.