Evidence of El Nino and the Indian Ocean Dipole from Sr/Ca derived SSTs for modern corals at Christmas Island, eastern Indian Ocean

Abstract

While the El Nino/Southern Oscillation (ENSO) has been regarded as an almost exclusively Pacific Ocean phenomenon, there is a growing amount of evidence that there are interannual events in other ocean basins which are possibly related to ENSO. Here we describe results from Sr/Ca analysis of a 24 year coral record from Christmas Island in the tropical eastern Indian Ocean. The Sr/Ca data was matched with blended ship and satellite data from the region to produce the Sr/Ca-SST calibration. There is evidence of both warm and cool SST anomalies in the Sr/Ca derived SSTs, with an extreme cooling event of 1994 relating to the unusual oceanographic conditions set up by the Indian Ocean Dipole (IOD) and warmer than normal SSTs corresponding with ENSO events in the Pacific.