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Currents and Climate. Surface Currents (ocean). Affect water to a depth of several hundred meters Driven by winds Move in circular patterns in 5 major oceans. Because of Coriolis effect – affects wind current movements because of Earth’s rotation. Northern hemisphere – curve to right
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Surface Currents (ocean) • Affect water to a depth of several hundred meters • Driven by winds • Move in circular patterns in 5 major oceans. • Because of Coriolis effect– affects wind current movements because of Earth’s rotation. • Northern hemisphere – curve to right • Southern hemisphere – curve to left
Gulf Stream • Largest, most powerful current in the North Atlantic Ocean. • Caused by strong winds from the west. • More than 30 km wide and 300 meters deep. • Carries more than 100 times the amount of water in the MS river. • Carries water from Gulf of Mexico to Caribbean Sea, then north.
Effects on Climate • Gulf Stream and North Atlantic Drift cause coastal areas to have temperate climates (little change in temperatures). • Currents affect climate by moving cold and warm water around the globe. • Causes air above the current to warm or cool. • Winds pick up moisture as they move across warm currents.
Wind Patterns • Trade winds flow through tropics – steer tropical storms in the ocean. • Prevailing westerlies move air masses and fronts. • Jet streams – fast flowing, narrow atmospheric currents. • Can significantly affect climate • Dust Bowl in 1930s – weak stream caused drought. • El Niño – greater precipitation in SE U.S. and Upper Midwest • La Niña – greater precipitation in Pacific NW.
Air Masses • Tropical – warm air • Polar – cold air • Maritime – forms over oceans – wet air • Continental – forms over land – dry air