Pacific Ocean To determine the phase of ENSO, the most recent three-month sea surface temperature average for the area approximately to the southeast of Hawaii is computed, and if the region is more than above or below normal for that period, then an El Niño or La Niña is considered in progress. In the tropical western Pacific, the monsoon and the related wet season during the summer months contrast with dry winds in the winter which blow over the ocean from the Asian landmass. Worldwide, tropical cyclone activity peaks in late summer, when the difference between temperatures aloft and sea surface temperatures
The Blob (Pacific Ocean) ultimate cause of the phenomenon, but states "there's no doubt that this anomaly in sea surface temperature is very meaningful". Sea surface temperature anomalies are a physical indicator which adversely affect the zooplankton (mainly copepods) in the Northeast Pacific and specifically in the Coastal Upwelling Domain. Warm waters are much less nutrient-rich than the cold upwelling waters which were the norm till recently off the Pacific Coast. This results in reduced phytoplankton productivity with knock on effects on the zooplankton which feed on it and the higher levels of the food chain. The Northwest Fisheries Science Center, Seattle has predicted