Anticyclones Flashcards
explain anticyclones in summer
as a result of high air pressure, there is little or no air rising upwards during an anticyclones. This means that little or no cloud can form. Without cloud there can be no precipitation. The lack of cloud allows a large amount of sunlight and heat to reach the Earth’s surface. Therefore in the summer anticyclones are usually associated with long, dry spells with hot temperatures. Sometimes the end of an anticyclone is marked by a convectional thunderstorm. The heat absorbed by ground and sea surfaces warms the air above it. This causes the air to become lighter and rise, forming large cumulonimbus thunder clouds
explain anticyclones in winter
In winter the lack of cloud can create very cold conditions. Clouds trap heat near the Earth’s surface at night. At night when there is no sunlight much of the heat that reached the Earth’s surface escapes out of the atmosphere into space. The very cold conditions at night can create thick frost. This can last throughout the day even when the sun is out. This is because in the winter the sun’s rays hit the Earth’s surface at a lower angle. This means that they are less intense. Any moisture on surfaces therefore freezes. Fog can form because of a temperature inversion. Most of the time the ground is warmer than the air above it. However, in winter, in the morning the ground can remain cold and frozen and is therefore colder than the air above it. This causes cloud to form at ground level
explain why thunderstorms sometimes occur at the end of an anticyclone
sometimes the end of an anticyclone is marked by a convectional thunderstorm. The heat absorbed by the ground and sea surface warms the air above it. This causes the air to become light and rise, forming large cumulonimbus thunder clouds
