Transcript WEATHER
WEATHER El Nino & La Nina El Nino Weaken from east Flows toward east Mild and wet Dry and cool La Nina WINDS WARM WATER U.S. WEATHER AUSTRALIA WEATHER Strengthen from east Move farther west Dry and warm in South Wet and cold in North Mild and wet Hurricanes HURRICANES WIND SPEED SIZE DURATION PROPERTIES 74 mph – 286 mph Up to 500 miles wide 2-4 weeks How does the ocean play a role in the formation? - A column of hot air from the Sahara that is three miles high spreads and picks up moisture from warm water (summer) and continues this process westward forming a tropical storm and then a hurricane. Rainfall Patterns Rains Winter Precipitation Summer Dry Little allprecipitation allyear rain, year rain, – summer all long from winter year, all –20° from dry year more to –-5° –from 32° infrom summer to8° 32° and 8° 70° to-15° to20° – to45° from 90° to and and 45° -30° and -5° -30° to to -65° 70° -15° toto-40° and -90° 40° to -65° Air Masses - Air masses are large bodies of air that are horizontally uniform in characteristics, like temperature and moisture content cP mP mP mT Co cT Continental = dry Maritime = moist mT Polar = cold Tropical = warm/hot Arctic = extremely cold Fronts and Pressure Systems • • • • • • • Front – boundary separating air masses, zone of transition Low pressure system – storm system, can travel thousands of miles and are responsible for the majority of precipitation High pressure system – Semi-permanent system that occupies the central portion of the Atlantic and Pacific – Large systems that represent large domes of cold air that follow lows Cold Front – cold air replaces warm air at the surface, most violent weather Warm Front – warm air replaces cold air at surface, usually northeast of a cold front Stationary front – doesn’t move, behaves like a warm front Occluded front – when cold front “catches” a warm front, mature storm systems Fronts and Pressure Systems Occluded Front Warm Front Stationary Front Global Forces - Winds Coriolis Effect Trade Winds The Earth’s Rotation causes surface currents to move in curved paths rather than a straight line. Affected by their latitude and the Coriolis Effect. In the tropics and poles, the winds blow from east to west. In the temperate climates, they blow from west to east. Polar Easterlies 90 ° 60° Westerlies 30 ° Tradewinds 0° Tradewinds 30° Westerlies 60 Polar Easterlies 90 Global Forces - Water Gyres Deep Ocean Currents Any large system of rotating ocean currents, particularly those involved with large wind movements -Deep cold currents move water toward equator -Cold water warms and rises to replace warm water leaving -Warm water travels on surface toward poles -Warm water replaces cold water