Mapping the 1986”1987 El Nino with GEOSAT altimeter data

The 1986–1987 El Nino was the first to be monitored by a satellite altimeter, and maps of sea level anomaly during the event reveal a rich and previously unknown structure. By chance, timing of the U.S. Navy GEOSAT altimeter mission was ideal for capturing this El Nino in its entirety. GEOSAT was launched in March 1985 and had gathered 1 full year of global data when an El Nino was predicted [Cane et al, 1986]. Dramatic atmospheric and oceanic changes were observed during the height of the event in 1986–1987, and by early 1988, conditions returned to normal. Throughout this 3-year period, GEOSAT provided virtually uninterrupted coverage of the tropical Pacific, and prospects for several more years of observations are excellent. In this brief report we present results demonstrating the enormous potential of satellite altimetry for application to large-scale ocean dynamics and climate research.