2.1 Global Atmospheric Circulation (Paper 1) Flashcards
<p>What are <b>Winds</b>?</p>
<p>Winds are large-scale air movements</p>
<p>What causes wind?</p>
<p>Wind is caused by differences in <b>air pressure</b></p>
<p>What causes differences in air pressure?</p>
<p>The difference in temperature between low and high latitudes (it is much warmer at the equator than at the poles) causes differences in air pressure</p>
<p>How does air pressure cause winds?</p>
<p>Wind moves from areas of high pressure to areas of low pressure</p>
<p>What are <b>westerlies</b>?</p>
<p>Westerlies are surface winds that blow in the direction of the poles</p>
<p>In the Northern Hemisphere, they blow from the south-west</p>
<p>What are <b>trade winds</b>?</p>
<p>Trade winds are surface winds that blow in the direction of the equator</p>
<p>In the northern hemisphere, they blow from the north-east</p>
<p>Where do surface winds blow from and to?</p>
<p>Winds blow from high pressure areas to low pressure areas</p>
<p>What is global atmospheric circulation?</p>
<p>The circular movements of the Earth's atmosphere. The circular movements of air are known as cells.These cells all join together to form the overall circulation of the Earth's atmosphere</p>
<p>Name the 3 main cells in the global atmospheric circulation model?</p>
<ol><li>Hadley Cell</li><li>Ferrell Cell</li><li>Polar Cell</li></ol>
<p>What is<strong>high pressure</strong>and where on the global atmospheric circulation model would you find high pressure?</p>
<p>When air sinks towards the ground, high pressure is formed</p>
<p>It happens at 30°N and 30°S of the equator, 90°N (North Pole) and 90°S (South Pole) of the equator</p>
<p>What is<strong>low pressure</strong>and where on the global atmospheric circulation model would you find high pressure?</p>
<p>When air is rising from the surface of the ground, low pressure is formed</p>
<p>It happens at 0° (the equator), 60°Nand 60°S of the equator</p>
<p>Describe what happens in the Hadley Cell?</p>
<p>Warm air rises at the equator, travels North and South and sinks around 30°N and 30°S. It then travels back to the equator</p>
<p>Describe what happens in the Ferrell Cell</p>
<p>Warm air rises at 60°N and 60°S equator, back towards the equator. Cool air sinks at30°N and 30°S of the equator</p>
<p>Describe what happens in the Polar Cell?</p>
<p>Cool air decends at 90°N (north pole) and 90°S (south pole) then the air moves back towards the equator</p>
<p>What are <b>deep ocean currents</b> caused by?</p>
<p>Deep ocean currents are caused by differences in water density</p>
<p>How does <b>Thermohaline circulation</b> work?</p>
<ul><li>Water freezes at the poles</li><li>The surrounding water becomes more salty and therefore more dense</li><li>Water begins to sink as its density increases</li><li>Sinking of dense water allows warm water to flow in at the surface</li><li>Warm water cools and sinks</li></ul>
<p>What are surface currents caused by?</p>
<p>Surface currents are caused by winds</p>
<p>What do surface currents do?</p>
<p>Surface currents transfer heat from the equator to cooler regions</p>
<p>Describe the Global Circulation system in detail</p>
<ul><li>At the equator, the Sun warms the Earth's surface. The Earth transfers this heat to the air, which then rises. This results in a low pressure belt with rising air, clouds, and rain</li><li>The rising air cools and moves towards 30° north and south</li><li>At 30° north and south, the cool air sinks resulting in a high pressure belt with no clouds and minimal rainfall</li><li>When the cool air reaches the ground, it moves as surface winds either towards the equator or the poles</li><li>At 60° north and south, cold air from the poles meets the warmer surface winds</li><li>The air splits with some returning back towards the equator and the rest heading to the poles</li><li>At the poles, cool air sinks and forms a high pressure belt which moves back towards the equator as surface winds</li></ul>
