Sea surface temperature temperature pattern is when warm water spreads from the west Pacific and the Indian Ocean to the east Pacific. It takes the rain with it, causing extensive drought in the western Pacific and rainfall in the normally dry eastern Pacific. El Niño's warm rush of nutrient-poor tropical water, heated by its eastward passage in the Equatorial Current, replaces the cold, nutrient-rich surface water of the Humboldt Current. When El Niño conditions last for many months, extensive ocean warming and the reduction in Easterly Trade winds limits upwelling of cold nutrient-rich deep water and its economic impact to local fishing for
Sea surface temperature satellite-derived SSTs within cloudy areas. However, passive microwave techniques can accurately measure SST and penetrate cloud cover. Within atmospheric sounder channels on weather satellites, which peak just above the ocean's surface, knowledge of the sea surface temperature is important to their calibration. The SST has a diurnal range, just like the Earth's atmosphere above, though to a lesser degree due to its greater specific heat. On calm days, the temperature can vary by . The temperature of the ocean at depth lags the Earth's atmosphere temperature by 15 days per , which means for locations like the Aral Sea, temperatures