Final answer:
Above average ocean temperatures occur due to the El Niño system, which is the warm phase of the El Niño Southern Oscillation (ENSO). El Niño is characterized by high air pressure in the western Pacific and low air pressure in the eastern Pacific, causing global changes in temperatures and rainfall.
Step-by-step explanation:
Above average ocean temperatures occur due to the El Niño system. El Niño is the warm phase of the El Niño Southern Oscillation (ENSO), characterized by a band of warm ocean water in the central and east-central equatorial Pacific. It is accompanied by high air pressure in the western Pacific and low air pressure in the eastern Pacific, causing changes in global temperatures and rainfall patterns.
On the other hand, La Niña is the cool phase of ENSO, which occurs when the sea surface temperature in the eastern Pacific is below average. It is characterized by high air pressure in the eastern Pacific and low air pressure in the western Pacific.
The California Current and the Gulf Stream are also important ocean currents, but they do not directly cause above average ocean temperatures like El Niño does.