Journal #35 What is the Coriolis Effect? In which direction does air flow?

Global Winds The air that flows from the poles toward the equator does not flow in a single straight line. Each hemisphere contains three looping patterns of flow called convection cells. Each of these convection cells correlates to an area of Earth’s surface called a wind belt. Pg 562 Wind belts are winds that flow in one main direction called prevailing winds.

Trade Winds In both hemispheres, the winds that flow toward the equator between 0 and 30 degrees latitude are called trade winds. Like all winds, the trade winds are named according to the direction form which they flow.

Trade Winds (Cont) In the northern hemisphere, the trade winds from the northeast are called the northeast trade winds. In the southern hemisphere, the trade winds are called the southeast trade winds. These wind-belts are called trade winds because many trading ships sailed on these winds from Europe in the 18 th and 19 th centuries.

Westerlies Between 30 and 60 degrees latitude, some of the descending air moving toward the poles is deflected by the Coriolis Effect. This flow creates the westerlies, which exist in another wind belt in each hemisphere. In the northern hemisphere, the westerlies are southwest winds. In the southern hemisphere, the westerlies are northwest winds.

Polar Easterlies Toward the poles, or poleward, of the westerlies at about 60 degress latitutde is a zone of low pressure. This low pressure separates the westerlies from a third wind belt. Over the polar regions, descending cold air creates areas of high pressure. The polar easterlies are strongest where they flow off Antarctica. Where the polar easterlies meet warm air fronts form (stormy regions).

Jet Streams Narrow bands of high-speed winds that blow in the upper troposphere and lower stratosphere are jet streams. These winds exist in the north and south hemispheres. Polar jet streams Subtropic jet streams

Local Winds Winds also exist on a smaller scale Movements of air are influenced by local conditions and local temperatures Local winds are not part of global wind belts. Winds that extend over distances of less than 100 km are called breezes.

Land and Sea Breezes Equal areas of land and water may receive the same energy from the sun, but land heats up faster than water. Therefore the temperature difference of land an water cause a circulation of air during the warm afternoon and early morning. Sea Breeze- Wind moving from water to land Land Breeze- Wind moving from land to water

Mountain and Valley Breezes During the day in mountainous regions, a light breeze blows upslope. This valley breeze forms when warm air from valleys moves upslope. At night, the mountains cool more quickly and this cool air descends down the mountains called mountain breeze.

Review Looping patterns of air flow are called ___ Prevailing winds that blow from east to west at 0 – 30 degrees latitude toward the equator are called ___. Wind that blow from west to east between degrees are called ___

Review What are jet streams? Where are jet streams found? In which direction do land breezes flow? In which direction do sea breezes flow? What causes the formation of land and sea breezes?

Review Which direction do valley breezes flow? Which direction do mountain breezes flow?