Depressions (low pressure) and Anticyclones (high pressure)

 Depressions (low pressure) and Anticyclones (high pressure)

Have a look to the transcription!

DEPRESSIONS ( Low Pressure) and ANTICYCLONES ( High Pressure)

(5 of 5)

So, what is a depression?

“Anything to do with breaking up of air speed”.

Depressions are air masses of low pressure.

Remember pressure is the weight of the atmosphere.

Depressions mean bad weather, in other words: rain, clouds and wind.

Depressions form when a warm air mass meets a cool air mass. This is how they work.

A warm air mass meets a cold air mass forcing the warm air to rise, this causes a warm front. Cold air undercuts warm air from behind to form a cold front.

The cold front, finally, catches up with the warm front, and warm air is squeezed upwards.

Low pressure at the centre of the depression causes winds.

The cold air makes the vapour in the warm air condensed often causing rain.

So, that’s bad weather caused by depressions.

Is there any weather system that causes good weather?

O yes, as a matter of fact, there is, there are called anticyclones.

In many ways, anticyclones are the exact opposite of depressions; they bring dry, bright and settled weather.

But what are they?

Anticyclones are air masses of high pressure.

Here is how they work.

Air descends; this creates an area of high pressure. The air is so warmed up as it descends which means it picks up moisture from evaporation, but there’s no condensation in an anticyclone, because the air is sinking not rising as it does a the depression.

This explains why there are no clouds and the weather is fine and dry.

In summer anticyclones cause light winds, sunshine and high temperatures.

But in winter, because there are no clouds, the heat escapes so, although it is bright and sunny, it’s cold and there’s often frost and sometimes fog.

SUMARY OF PART 5.

In this part we’ve learnt that:

Depressions are air masses of low pressure, but

Anticyclones are air masses of high pressure.