OCEAN INTERACTIONS WITH THE ATMOSPHERE Niki Henzel & Ron Gabbay

Ocean interaction with the atmosphere Wind from the atmosphere affects the oceanic currents Heat from the ocean affects heat circulation

El Nino-Southern Oscillation a periodic, large-scale warming of surface waters of the tropical eastern Pacific Ocean that temporarily alters both ocean and atmosphere circulation patterns Responsible for most of earth’s interannual climate variability Most ENSO’s last 1-2 years Originates in the tropical Pacific Has a periodicity of 2-7 years Results: some areas become drier, wetter cooler, or warmer than usual

El Nino A global effect of ENSO Trade winds weaken and the warm mass of water, which expands eastward towards South America which increases surface temperature in the East Pacific Ocean currents, which normally flow westward in this area slow down, stop, or reverse (go eastward) Called “El Nino - boy child” b/c the warming usually reaches fishing grounds off Peru right before Christmas

La Nina Occurs when surface water temperature in the eastern Pacific Ocean becomes unusually cool and westbound trade winds become unusually strong Occurs after an “El Nino” event Effects are difficult to predict Causes wetter winters in Pacific Northwest, warmer weather in Southeast, drought conditions in the Southwest, and Atlantic hurricanes are stronger and more numerous

ENSO Effects on US Typically, northern areas are warmer during the winter, whereas southern area are cooler and wetter Gulf states cooler and wetter California can be wetter or drier Pacific salmon and other fisheries disrupted Fewer hurricanes in the Atlantic

ENSO’s affect on the fisheries in South America Normally, cold, nutrient rich deep water is 135 ft below the surface and up wells along the cost back of strong trade winds During ENSO the same water is 500 ft below the surface temperatures and weak trade winds prevent upwelling Lack of nutrients in the water (during ENSO) results in a severe decrease in the population of anchovies and other marine fishes

Links and Videos Link: Video: yM4G6nSafM yM4G6nSafM

FUN FACTS! Enso forecasts improve the accuracy of seasonal and longer forecasts over the US Potential for billions of dollars in benefits to the US economy in: agriculture, energy generation, water resources, forestry, fisheries, transportation, commerce,public health Total cost of these ocean observations is $4.9 million per year