English: This illustration of Earth's sea surface temperature was obtained from two weeks of infrared observations by the Advanced Very High Resolution Radiometer (AVHRR), an instrument on board NOAA-7 during July 1984. Temperatures are color coded with red being warmest and decreasing through oranges, yellows, greens, and blues. Temperature patterns seen in this image are the result of many influences, including the circulation of the ocean, surface winds, and solar heating. The image indicates a large pool of warm water in the Western Pacific and a tongue of relatively cold water extending along the Equator westward from South America. Every few years, there occurs an interrelated set of changes in the global atmospheric and oceanic circulation known as an El Ni±o in which the region of warm equatorial water in the West extends eastward across the Pacific and blankets the cool, productive regions along the coast of South America. Fish, birds, and marine mammals that depend upon the normally phytoplankton-rich waters often die in large numbers during El Ni±o. Images of sea surface temperature such as this help scientists to better monitor and ultimately understand the changes to Earth caused by events such as El Ni±o.