Pacific ENSO Update

2nd Quarter, 2006 Vol. 12 No. 2

SEA SURFACE TEMPERATURE (SST)

Sea surface temperature (SST) anomalies increased by more than 2°C in the extreme eastern equatorial Pacific during April, and by the end of the month, positive equatorial SST anomalies greater than +0.5°C (~0.9°F) were observed in most areas from Indonesia eastward to the South American coast. The increase in SST anomalies in the eastern equatorial Pacific during April was reflected by an increase in the SST anomalies in the Niņo 3 and Niņo 1+2 regions and by an increase in the upper-ocean heat content in the eastern half of the equatorial Pacific. Subsurface cooling and a decrease in upper-ocean heat content have been evident in the central equatorial Pacific, associated with the upwelling phase of the Kelvin wave. This cooling is expected to propagate eastward, reaching the eastern equatorial Pacific during Feb...