controls weather and climate around the world What is meant by the key term latitude Learning Objective To identify how the movement of air between the poles and the equator can lead to differences in weather and climate ID: 1043603
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1. Sunday, 08 March 2020What controls weather and climate around the world?What is meant by the key term ‘latitude’?Learning Objective: To identify how the movement of air between the poles and the equator can lead to differences in weather and climate.
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3. LatitudeWrite out this paragraph which explains about the effect that latitude has on temperature. Choose the correct word where directed.The most important influence on the temperature of a place is its line of latitude/longitude. Places that are closer to the Equator/Tropic of Cancer will have higher temperatures. The polar regions have lower/higher temperatures because the curvature of the Earth's surface reduces the concentration of the sun’s rays.
4. High and Low PressureAreas of high and low pressure are caused by rising and sinking air. Low pressure (depressions) are caused as warm air rises then cools and forms clouds which eventfully rain. Winds are common as air rushes in to fill the vacuum created as the air rises. With high pressure (anticyclones) heavier cooler air is sinking . This means that there are long periods of stable weather with no rainfall.Cold air sinksWarm air rises
5. Global Atmospheric CirculationGlobal atmospheric circulation leads to areas of high rainfall, like tropical rainforests, and areas of dry air, like deserts.How?Where air is sinking in the model this gives high pressure. These areas coincide with many of the earth’s deserts and dry areas as the air is sinking so little condensation occurs.Where air is rising in the model this gives low pressure. These areas coincide with wetter areas with lush vegetation as air cools as it rises, allowing water vapour to condense to droplets allowing more rain. Winds occur because air molecules move from areas of high pressure to areas of low pressure.https://www.youtube.com/watch?v=7fd03fBRsuU https://www.youtube.com/watch?v=xqM83_og1Fc
6. Global Atmospheric CirculationUse the information that you have been given to annotate your model to show what happens in each cell.
7. Polar CellThe Arctic and the Antarctic are deserts due to constant high pressure leading to very low levels of precipitation.What happens in the Polar cell (at the poles-90°)?The air sinks over the higher latitudes at the poles and flows towards the mid-latitudes where it meets the Ferrel cell and rises. Descending cool, dry airRising warm, moist air
8. Ferrel CellThe UK is located within the Ferrel cell. This explains our mild/temperate climate.What happens in the Ferrel cell (30-60° N and S)?Air in this cell joins the sinking air at the edge of the Hadley Cell. It travel across mid-latitude regions until the air rises along the border of the Polar cell. Descending cool, dry airRising warm, moist air
9. Hadley CellThe Sahara Desert due to little cloud and rainfall and also tropical rainforests can be found within the Hadley cell. What happens in the Hadley cell (Equator-30° N and S)?Winds meet near the Equator and the warm air rises, causing thunderstorms. The drier air then flows outwards towards 30° before sinking. Descending cool, dry airRising warm, moist air
10. Global Atmospheric CirculationUse the information that you have been given to annotate your model to show what happens in each cell.
11. Distribution of Main Climatic RegionsThe main climatic regions of the world include:PolarTemperateSub tropical (deserts)Tropical
12. ActivityTropical ClimateThis is a belt of relatively low pressure, heavy rainfall and thunderstorms as a result of rising air in the Hadley Cell. Northern Brazil and Malaysia experience this climate.Polar ClimateAt the highest latitudes, cold air from the Polar cell sinks, producing high pressure. This is characterised by cold, icy winds.Temperate ClimateIn the mid latitudes, 50° to 60° north and south of the Equator, two air types meet, one warm from the Ferrell Cell and one cold from the Polar Cell. Low pressure is caused from the rising of the warm, sub-tropical winds over the cold, polar winds. As this air rises and cools, it condenses to form clouds and frequent rainfall. This is typical of the UKSub-tropical (Desert) ClimateAt 30° north and south of the Equator there is high pressure as a result of sinking, dry air as the Hadley and Ferrell cells meet. This creates a belt of desert regions including the Sahara Desert in Northern Africa. Locate the climatic regions on your map and describe key features of each one.
13. Puerto Lopez Colombia is one of the world’s most wettest places on Earth. In the mid 1980s it rained every single day for 2 years!Vostok in Antarctica is the coldest place on Earth. In 1983 the coldest air temperature was ever recorded here at -89.2°C. Al Aziziyah in Libya is the hottest place on Earth. In 1922 the hottest air temperature was ever recorded here at 57.8°C. Aswan in Egypt is one of the driest areas in the world with only 0.861mm of rain per year. Extreme Weather Conditions
14. PlenaryKey WordDefinitionClimatic Zonethe imaginary lines that surround the Earth ranging from 0° at the Equator to 90° at the poles.Latitudeoccurs when there is more air pressing down on the ground caused by air sinking.Atmospheric air pressuredivisions of the Earth’s climates into belts or zones, according to average temperatures and rainfall.High pressurethe force exerted on the Earth’s surface by the weight of theair (measured in millibars).Low pressurethe movement of air around the Earth that distributes heat.Atmospheric circulationa boundary that separates two masses of air with different densities, usually heavier cold air and lighter warm air.Front.occurs when the air is rising, so less air is pressing down on the ground.Using your knowledge about global air circulation can you define the key terms we used in today’s lesson?
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17. The Hadley cellThe first cell is called the Hadley cell. At the equator, the ground is intensely heated by the sun. This causes the air to rise which creates a low-pressure zone on the Earth's surface. As the air rises, it cools and forms thick cumulonimbus (storm) clouds. The air continues to rise up to the upper atmosphere, and the following then happens:The air separates and starts to move both north and south towards the poles.When it reaches about 30° north and south, the air cools and sinks towards the ground forming the subtropical high-pressure zone.As the air sinks, it becomes warmer and drier. This creates an area of little cloud and low rainfall, where deserts are found.The Ferrel cellThe Ferrel cell occurs at higher latitudes (between 30 degrees and 60 degrees N and S):Air on the surface is pulled towards the poles, forming windThese winds pick up moisture as they travel over the oceans. At around 60 degrees N and S, they meet cold air, which has drifted from the poles.The warmer air from the tropics is lighter than the dense, cold polar air and so it rises as the two air masses meet.This uplift of air causes low pressure at the surface and the unstable weather conditions that are associated with the mid-latitude depressions. Much of our wet and windy weather in the UK is determined by this.The Polar cellAt the poles, air is cooled and sinks towards the ground forming high pressure, this known as the Polar high. It then flows towards the lower latitudes. At about 60 degrees N and S, the cold polar air mixes with warmer tropical air and rises upwards, creating a zone of low pressure called the subpolar low. The boundary between the warm and cold air is called the polar front. It accounts for a great deal of the unstable weather experienced in these latitudes.
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