Today’s goals… I can explain the effect of the Sun’s energy on Earth’s systems. Including the water cycle and winds.
Review Convection When particles in the air are heated, they move more rapidly and spread apart The air becomes less dense and is moved upward When cooled, the particles move more slowly and closer together The air becomes more dense and it sinks
Heated Air Areas of Earth receive different amounts of radiation because the Earth is curved See Figure 15 Which areas receives the most direct sunlight? The least? Equator Poles
Heated Air At the equator air is heated and rises, forming a low pressure area As the air moves away from the equator it cools and sinks and most returns to the equator as trade winds, some flows on to the poles This creates convection currents
Forming Wind Wind is the movement of air from an area of higher pressure to an area of lower pressure This is caused by the uneven heating of Earth’s surface
The Coriolis Effect The Coriolis effect makes the winds appear to be curving to the west as they travel to the equator This contributes to weather patterns as well as to where and when planes fly and ships sail See page 104, Figure 16 More
Doldrums Trade winds meet, calm area Recall the water cycle Warm air at the equator rises and cools causing a low pressure area Cloudy, rainy weather is common here
Prevailing Westerlies 30 – 60 degrees latitude The winds that flow toward the poles appear to curve from west to east Responsible for many of the weather movements across the US and Canada
Polar Easterlies The cool air flows away from the poles and is deflected from the east toward the west by the coriolis effect
Winds in the Upper Troposphere Jet streams are narrow belts of strong winds that blow near the top of the troposphere It helps move storms across the country Pilots also take advantage of the jet streams
Sea Breezes Convection currents over areas where the land meets the sea can cause winds Created during the day because solar radiation warms the land more than the water
Sea Breezes Warm air over the land rises, creating an area of low pressure Cool air over the water has higher pressure and flows toward the warmer, less dense air
Land Breezes The opposite occurs at night when land cools more rapidly than water The cool air over land moves toward the warmer air over the water
Review Questions What causes wind? What surface winds move weather across the US? What deflects wind to the right north of the equator and to the left south of the equator? What winds do pilots take advantage of to save fuel and time? What type of wind is a movement of wind toward water?
Exit Slip 3-Sentence Wrap-Up In 3 sentence or less, sum up today’s lesson. Focus on the important parts!