El Niño
The cyclical warming of East Pacific Ocean sea water temperatures off the western coast of South America that can result in significant changes in weather patterns in the United States and elsewhere. This occurs when warm equatorial waters move in and displace the colder waters of the Humbolt Current, cutting off the upwelling process.
Sea Surface Temperature (SST)
The temperature of the water’s surface. It is measured using buoy and ship data, infrared satellite imagery, and coastal observations.
Weather
The state of the atmosphere at a specific time and with respect to its effect on life and human activities. It is the short term variations of the atmosphere, as opposed to the long term, or climatic, changes. It is often referred to in terms of brightness, cloudiness, humidity, precipitation, temperature, visibility, and wind,
Equator
The geographic circle at 0 degrees latitude on the earth’s surface. It is equal distance from the North and South Poles and divides the Northern Hemisphere from the Southern.
Humbolt Current
Also known as the Peru Current, this ocean current flows northward along the western side of South America, offshore Chile and Peru. There is considerable upwelling of the colder subsurface waters due to the prevailing southerly winds. Dominant weather in this area includes coastal fog and low clouds. The presence or lack of this current is a vital part of the meteorological-oceanographic pattern known as El Niño.
Upwelling
The process by which water rises from a lower to a higher depth, usually as a result of divergence and offshore currents. It influences climate by bringing colder, more nutrient-rich water to the surface. A vital factor of the El Niño event.