CLIMATES: weather mechanisms
Weather Mechanism:
Earth's air and water work together like a gigantic machine powered by heat from the Sun. The sun heats the Earth irregularly :
> Intensely the equatorial regions.
> Very weakly the polar regions.
Air and water distribute this heat. The heat is carried towards the poles by ocean currents and planetary winds. The constant mixing, maintained by the planet's rotation, also brings water and cold air to the equator, where they heat up.
This time machine gives us wind, rain, snow, mist or fog. These meteorological phenomena can be explained by a few simple principles of physics.
> Very weakly the polar regions.
Air and water distribute this heat. The heat is carried towards the poles by ocean currents and planetary winds. The constant mixing, maintained by the planet's rotation, also brings water and cold air to the equator, where they heat up.
This time machine gives us wind, rain, snow, mist or fog. These meteorological phenomena can be explained by a few simple principles of physics.
Invisible water!
As heated water evaporates, it turns into an invisible gas, or vapor, which mixes with air. The amount of water vapor that air can contain depends on its temperature; Thus, hot air contains a lot of it, and cold air contains little.
When hot air cools, its water vapor turns into liquid water : this process is called condensation. So, it is the condensation which deposits the mist on the windows of a car; and we also steam when we breathe on a very cold day. This same process is responsible for the formation of fog on cool nights, and clouds when warm air rises and cools.
When hot air cools, its water vapor turns into liquid water : this process is called condensation. So, it is the condensation which deposits the mist on the windows of a car; and we also steam when we breathe on a very cold day. This same process is responsible for the formation of fog on cool nights, and clouds when warm air rises and cools.
High pressure :
Air is very light, but it still has weight. That of the air in a given place is called atmospheric pressure. When the air is cold, it slowly descends compressing the air below it, which increases the pressure. Although due to cold air, the high pressures are accompanied by fine sunny weather, as the descending air prevents cloud formation and clears the sky.
Low pressure :
When hot air rises from the ground, it creates an area of low pressure below it, usually causing bad weather. As the rising air cools, its water vapor turns into clouds, sometimes bringing rain, snow or thunderstorms. At the same time, air descends towards the ground to take the place of the rising hot air, which creates wind. The weather is more variable during periods of low pressure.
Float in the air !
When the air heats up, it expands, becomes lighter and rises. This process, called convection, allows hot air balloons to float. A burner heats the air in the hot air balloon, making it lighter than the surrounding air : it can therefore rise.
Air is constantly circulating between the higher and colder regions of our atmosphere, and the lower and warmer regions. Thus, the hot air which rises cools; Then the cold air obtained is heavier than the hot air : it therefore falls back to the ground.
Air is constantly circulating between the higher and colder regions of our atmosphere, and the lower and warmer regions. Thus, the hot air which rises cools; Then the cold air obtained is heavier than the hot air : it therefore falls back to the ground.
The fronts :
When a mass of cold air from the poles comes into contact with warm air from the tropics, the two masses do not mix well. A transition zone, called a forehead, forms between the two. The cold (heavier) air creeps under the warm air mass, pushing it upwards with formation of clouds. If the air moves faster to one side of the forehead, it results in the formation of an area of low pressure called depression. The depressions produce cloud eddies that can be seen very clearly in the photos taken with the setellites.
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