The El Niño/La Niña event in 1997-1999 was particularly intense, but was also very well observed by satellites and buoys. A strong upwelling of unusually warm water was observed in the Pacific Ocean during the El Niño phase, followed by unusually cold water in the La Niña phase. The Advanced Very High Resolution Radiometer (AVHRR) instrument on the US National Oceanic and Atmospheric Administration's NOAA-14 spacecraft observed the changes in sea surface temperature shown here.
This animation shows El Niño and La Niña from
1997 through 1998. Each frame is a ten-day average of sea
surface temperature (SST) anomalies—that is, of differences from
normal SST values. The area shown in the animation is the
Pacific ocean from -20.5 to +20.5 latitude and +120.5 to +289.5
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 188.8.131.52.0