Chapter 10

Atmosphere Ocean Interactions Global Winds and Surface Ocean

CurrentsOcean surface dragged by wind, basins

react to high pressure circulation forming gyres

Cold current, flowing north to south, on west side of continent

Warm current, flowing south to north, on east side of continent

Oceanic front

Stepped Art

Fig. 10-14, p. 273

Atmosphere Ocean Interactions Upwelling

Ekman spiral, Ekman transportWater moving away from the coast causes

upwelling

Fig. 10-16, p. 273

Fig. 10-17, p. 273

Fig. 10-18, p. 274

Atmosphere Ocean Interactions El Nino and the Southern Oscillation

El Nino: irregular warm episode off west coast of South America

Southern Oscillation: rise in pressure over W Pacific, fall in the E Pacific, equatorial countercurrent

ENSOLa Nina (cold waters off the coast of South

america indicating strong upwelling)teleconnections

http://www.pmel.noaa.gov/tao/jsdisplay/

Conditions Fall 2010. For latest update see link below. The Pacific Decadal Oscillation is also presently in its cool phase so colder than average and wetter than average winter is expected this coming winter.

Fall 2010 values are negative indicating a significant La Nina this Fall.

Atmosphere Ocean Interactions Pacific Decadal Oscillation

Reversal in Pacific Ocean temperatures Warm = more Pacific stormsCool = cool, wet NW North America, wetter

over the Great Lakes, salmon fisheries decline

Atmosphere Ocean Interactions North Atlantic Oscillation

Reversal of pressure in North Atlantic Ocean affecting weather in Europe and eastern coast of North America

Positive = strong Westerlies, storms in N Europe, wet and mild in eastern US

Negative = wet southern Europe and Mediterranean, cold and dry in eastern US

Atmosphere Ocean Interaction Arctic Oscillation

Closely related to NAOPressure changes between Arctic and

adjacent southern areas causes changes upper-level winds

Positive = mild winter in US and W EuropeNegative = cold US, cold dry Europe, wet

Mediterranean