Why is atmospheric pressure low at the equator

Some of the descending air in the subtropical belt forms surface winds which return towards the equator. Here they collide with cold polar air, and the warm air is forced to rise, developing a zone of low pressure. This temperate low-pressure zone is cyclonic in nature, and is associated with the development of frontal depressions. Such weather features are common to the UK and bring with them bouts of rain and intermittent sunshine.

Depressions are more dominant in winter than in summer. During the warmer half of the year, subtropical high-pressure systems sometimes expand poleward to have a calming influence on the weather in the temperate latitudes. The very low temperatures over the polar regions make the air there heavy, forcing it to descend, creating a zone of high pressure. The permanent and thick snow and ice cover in the Antarctic and Arctic regions give false impression that they receive a lot of snowfall.

In fact, the polar regions can be as dry as the hot deserts of the subtropical climate zone , and it can take many years for even small amounts of snowfall to accumulate. Give a geographical reason for each of the following: Low atmospheric pressure prevails over the Circum-polar region. View Answer Bookmark Now. What are the Jet Streams? What is the significance of the Jet Streams? Above every square inch on the surface of the Earth is That means air exerts High in the atmosphere, air pressure decreases.

With fewer air molecules above, there is less pressure from the weight of the air above. This is, in part, because the Earth is not equally heated by the Sun. Areas where the air is warmed often have lower pressure because the warm air rises.

These areas are called low pressure systems. Places where the air pressure is high, are called high pressure systems. A low pressure system has lower pressure at its center than the areas around it. Winds blow towards the low pressure, and the air rises in the atmosphere where they meet. As the air rises, the water vapor within it condenses, forming clouds and often precipitation.

This is called cyclonic flow. On weather maps, a low pressure system is labeled with red L. A high pressure system has higher pressure at its center than the areas around it.