Why Air Moves Wind is created by differences in air pressure As HOT AIR RISES it creates an area of LOW PRESSURE As COOL AIR SINKS it creates an area of HIGH PRESSURE

Pressure Belts As HOT AIR RISES it creates an area of LOW PRESSURE HOT AIR RISES at the equator creating a LOW PRESSURE BELT As COOL AIR SINKS it creates an area of HIGH PRESSURE COOL AIR SINKS away from the equator creating a HIGH PRESSURE BELT * Air moves from areas of HIGH PRESSURE to LOW PRESSURE

Coriolis Effect The movement of wind is affected by the rotation of the Earth The Earth ’ s rotation causing wind to move in a curved path The winds in the Northern Hemisphere curve to the right The winds in the Southern Hemisphere curve to the left CORIOLIS EFFECT: the curving of an object due to the rotation of the Earth. * Air moves from areas of HIGH PRESSURE to LOW PRESSURE

Gustave-Gaspard Coriolis A French mathematician, engineer and scientist who studied the transfer of energy in rotating systems (like a waterwheel). He published his findings in 1835, but they weren’t connected to meteorology until the 20 th century. He was the first person to use the term “work” in relation to energy. He died in 1843 at the age of 51 in Paris. His name is one of the 72 names inscribed on the Eiffel Tower.

Big Bertha and Long Max The German army built 2 huge guns near the end of WW1 to attack Paris. They could fire artillery more than 60 miles but consistently missed by ½ mile to the west. It is thought that they fell victim to the Coriolis Effect. Coriolis Effect Animation (click to see)

Types of Winds: Global Winds Trade Winds:blow towards the equator. Early merchants sailed from Europe to the Americas to TRADE. Doldrums:low pressure at the equator with very little winds. Horse Latitudes:areas of weak winds away from the equator. Trade ships used to get stuck in these winds and throw horses overboard to save water for the sailors. Westerlies: wind belts at 30˚ and 60˚ latitude blowing opposite the trade winds often helped sailors return to Europe. Polar Easterlies: wind belts near the poles formed from cold, sinking air moving away from the poles. * Air moves from areas of HIGH PRESSURE to LOW PRESSURE

Excerpt: RIME OF THE ANCIENT MARINER Samuel Taylor Coleridge The fair breeze blew, the white foam flew, The furrow followed free:(The trades) We were the first that ever burst Into that silent sea Down dropt the breeze, the sails dropped down, Twas sad as sad could be; And we did speak only to break(The doldrums) The silence of the sea! All in a hot and copper sky The bloody Sun, at noon,(Vicinity of the ITCZ) Right up above the mast did stand, No bigger than the moon. Day after day, day after day, We stuck, nor breath nor motion: As idle as a painted ship Upon a painted ocean.

Types of Winds: Local Winds Sea Breeze:During the day, the land heats up faster than water. The land heats the air and it rises. The cool air from the sea moves toward the land. Cool air over the water = high pressure. * Air moves from areas of HIGH PRESSURE to LOW PRESSURE

Types of Winds: Local Winds Land Breeze: During the night, the land cools faster than water. The land cools the air creating an area of high pressure. The cool air moves out to sea producing a land breeze. * Air moves from areas of HIGH PRESSURE to LOW PRESSURE

Valley Breeze:During the day, the valley warms up heating the air. Warm air rises creating a valley breeze. Local Winds * Air moves from areas of HIGH PRESSURE to LOW PRESSURE

Mountain Breeze: During the night, the mountains cool faster than the valley. The cool air sinks to the valley creating a mountain breeze. Local Winds * Air moves from areas of HIGH PRESSURE to LOW PRESSURE