AN EMPIRICAL ORTHOGONAL FUNCTION-ANALYSIS OF REMOTELY-SENSED SEA-SURFACE TEMPERATURE VARIABILITY AND ITS RELATION TO INTERIOR OCEANIC PROCESSES OFF BAJA-CALIFORNIA

Empirical orthogonal function (EOF) analysis was applied to a 4.6-year sequence of AVHRR images off Baja California centered near Punta Euge nia to examine large- and mesoscale processes in this region of the Ca lifornia Current System (CCS). The mean structure found in the image s equence describes the seasonal cycle in sea surface temperature (SST) and the large-scale, north-south, oceanic SST gradient of the region. The first EOF-amplitude pair also describes the seasonal cycle in SST. Both results are consistent with long-term, large-scale, mean ship-bo ard data for the region. The second EOF-amplitude pair defines two dis tinct regions paralleling the coast. The inshore region coincides with the coastal zone of Lynn and Simpson (1987), and the adjacent region farther offshore is identical to their transition zone. The third thro ugh fifth EOF-amplitude pairs primarily represent meandering of the Ca lifornia Current and anticyclonic mesoscale eddy occurrences in the re gion; these results also are consonant with a large number of shipboar d observations. The EOF results provide independent satellite-derived evidence for the existence of a transition zone off Baja California wh ich is similar to that found off central and southern California. More over, the agreement between the satellite-based results and the shipbo ard observations indicates that satellite data can be used successfull y to study other current systems (e.g., Peru Current), where in situ o bservations (ships, buoys) are less abundant.