Satellite derived sea surface temperature variability in the Western Tropical Pacific Ocean, 1992–1993

One year of NOAA Advanced Very High Resolution Radiometer (AVHRR) global area coverage (GAC) infrared satellite data from September 1992 to August 1993 were processed into 10-day composite sea surface temperature (SST) maps, which show the variability of SST in the Western Tropical Pacific Ocean (including the TOGA COARE area). In situ SST measurements from moored buoy data were used to validate the satellite SST products revealing the multichannel SST (MCSST) to be most representative of the buoy SSTs. An empirical orthogonal function (EOF) analysis was performed to characterize the principal components of the annual SST variability. The first EOF mode (64.2% of the variance) indicates that the variance of the satellite derived MCSST has a strong meridional structure with a marked seasonal modulation. This first mode suggests the importance of “warm pool” with a maximum just south of the equator at about 170°E. The second mode (8.7% of the variance) and the rest of the EOF modes show more complex spatial structures. The large amount of variance explained by the first mode compared to the second mode indicates that the seasonal variance of the warm pool dominates all other variability. This strong seasonal behavior is also clearly seen in the monthly meridional position of the Intertropical Convergence Zone (ITCZ). The annual mean SST map shows a persistent warm pool from 13° S to 10° N and 130° E to 170° W, which is larger than the COARE intensive observing period (IOP) domain. Monthly SST means in the region suggest a seasonal cycle in phase with the solar cycle. Warm pool total area variance and its centroid movement demonstrate similar annual cycles.