Transcript Winds
Solar Heating Exchange Weather Patterns Storm Disturbances Uneven Solar Heating and Atmospheric Circulation What factors govern the global circulation of air? Uneven solar heating The Coriolis effect 7/21/2015 2 Uneven Solar Heating and Latitude Earth as a whole is in thermal equilibrium, but different latitudes are not. Moving masses of air and ocean currents transport energy from locations with a surplus to those with a deficit. 7/21/2015 3 Atmospheric Circulation Atmospheric circulation is powered by sunlight. Since Earth is in thermal equilibrium, what assumption can be made about the input and output of heat on Earth? 7/21/2015 4 The Coriolis Effect The Coriolis effect is the curving effect observed by a person of a object moving into space, caused by the revolving Earth. As air warms, expands, and rises at the equator, it moves toward the pole, but instead of traveling in a straight path, the air is curved eastward. In the Northern Hemisphere air turns to the right. In the Southern Hemisphere air turns to the left. 7/21/2015 5 The Coriolis Effect Air moves in cells, influenced by the Coriolis effect. 7/21/2015 6 Wind Bands The Trade Winds are easterly winds located from 0 degrees to 30 degrees N/S. The Prevailing Westerly winds are located from 30 to 60 degrees N/S. The Polar Easterlies winds are located from 60 to 90 degrees N/S. 7/21/2015 7 The easterly trade winds of both hemispheres converge at an area near the equator called the "Intertropical Convergence Zone (ITCZ)", producing a narrow band of clouds & thunderstorms that encircle portions of the globe. 7/21/2015 8 Pressure Zones The Doldrums at 0 degree is a calm equatorial area of Low pressure. The Horse Latitudes are High pressure areas with little surface wind which are located at 30 degrees N/S. The Subpolar Zones are Low pressure areas located below the north and south poles at 60 degrees N/S 7/21/2015 9 Wind and Pressure Patterns 7/21/2015 10 Sea Breezes and Land Breezes Top: Sea breeze Onshore movement of air as inland air heats and rises. ( in afternoon) Bottom: Land breeze Offshore movement of air as marine air heats and rises. ( in evening) 7/21/2015 11 STORM FORMATION 1. 2. 3. 4. Low pressure zones ( high pressure moves to low) Coriollis effect=cyclonic winds ( counterclockwise) Begins at 5-30 degrees latitude U.S. weather moves from Nw, Sw, Se then out Ne TORNADOES 1. 2. 3. 4. 5. From thunderstorms winds of 40-65 mph Highest speeds 300 mph Cause is steep pressure change Form over, warm , dry areas Eastern Great Plans most common area 7/21/2015 12 Nor’easter When a storm low stops moving, its winds combine with those of the neighboring high pressure system to blow in one direction over a long period of time, which creates huge waves. The duration of a Nor'easter, & the number of high tides through which it persists, can be the most significant measure of its destructiveness. Storms Large tropical cyclones are called hurricanes. The vertical dimension is exaggerated in this model of a hurricane. 7/21/2015 14 Storms The orange shaded areas and arrows designate the location and movement of most hurricanes. 7/21/2015 15 A hurricane originating in the eastern tropical Atlantic, for example, is driven westward by easterly trade winds. Eventually, these storms turn northwestward around the subtropical high and migrate into higher latitudes. TROPICAL CYCLONE FORMATION Stages of Development Tropical Easterly Wave ( Tropical Disturbance) Thunderstorms and light winds Tropical Depression Wind < 39 mph, pressure falls or Tropical Storm Winds 39-73 mph Hazardous seas Hurricane Winds 74 mph or more 7/21/2015 17 TURBULENCE FEAR IS IN THE AIR 7/21/2015 18 The End Press “esC” to exit slide show