Transcript Winds
Winds What is Wind? The horizontal movement of air from High pressure to Low pressure. • HL Air moving up or down (vertical) is called a current Pressure is caused by the characteristics of the air Warmer Air X X X X X X X X X X X X Molecules move faster and are farther apart. Less Dense Cooler Air More Dense X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Molecules are close together and move slowly. Warm Air Rises Cool Air Sinks Warm Air Rising Warm Air Rising Cool Air Sinking Convection Currents Cool Air Sinking Cool Air Sinking Warm Air Rising High Pressure Ok, High Pressure is 1. Dense (heavy) 2. Cool 3. Creates Clear Skies Low Pressure Ok, Low Pressure is 1. Less Dense (heavy) 2. Warmer 3. Brings Lousy Weather High Pressure Low Pressure = = Happy Weather Lousy Weather HL In a high pressure area, air will (rise, sink) because the air is (less, more) dense. This is because the air is (cold, warm) and (rises, sinks). Therefore, clouds CANNOT form. In a low pressure area, air will (rise, sink) because the air is (less, more) dense. This is because the air is (cold, warm) and (rises, sinks). Therefore, clouds are LIKELY to form. There Are Two Kinds of Winds: Global and Local • Global Winds are Winds that blow over long distances around the Earth. • Local Winds are winds that blow a short distance. Global Winds Why Do Different Parts of the Earth Have Different Temperatures? North Pole Equator South Pole Thus, radiation is more intense near the equator compared to the poles. For this reason, it’s warmer near the equator than at the poles. Global Thermal Temperatures Air Rises at the Equator • Air at the Equator is warm. • Warm air rises. • The Equator is a Low Pressure area. What Happens to Rising Air at the Equator? • At the Equator, air rises; • As the air moves upward, it cools, • The air begins to turn to move downward. • Cold air sinks at the 30o zone. Winds blow from High Pressure to Low Pressure Let’s Label High Pressure 90°N Low Pressure 60 °N High Pressure 30°N Low Pressure 0° High Pressure 30°S Low Pressure 60°S High Pressure 90°S Why Don’t The Winds Blow in Straight Lines? • Cold air from both the South Pole and North Pole blows towards the 60o zone • But the air doesn’t flow in a straight line Coriolis Effect • Since the earth rotates, winds do not blow directly from north to south or south to north. • Winds curve • They curve because the earth rotates or spins on its axis. • The Coriolis Effect is the curving of winds due to the earth’s rotation. The ball is going straight, but it looks like it is curving. Local Winds • Winds that blow short distances and in any direction (depending on pressure) • Remember, winds always blow from areas of high pressure to low pressure.