when there is high pressure, the climate is very dry and the sun shines brightly. why?

Question

but, you see in low atmospheric pressure, the climate is very bad and it rains a lot. also higher the altitude is, the pressure is very low. is the deserts are hot due to there very high pressure?. how are these high and low pressure formed in atmosphere?. also, i heard that as the pressure increases, the tempreture also increases. is that true? what is high and low pressure actually? please i kindly request you to explain me all these with your good explanation.

Answer 1

High and low pressure refers to the pressure caused by the mass of air above a point on the surface. If there is less air, the pressure is low, if there is more, the pressure is high. How do we get more or less air above a point?

Here we have to consider a concept that doesn't really exist but helps to explain what is happening. Imagine two columns of air, one at the equator and one further away. The column at the equator is going to be heated by the sun and it will expand. At the surface, the pressure remains the same but higher up, at any level, there will be more air in the expanded column than in the unaffected one. More air means higher pressure so air will flow, at some height above the ground, from the expanded column towards the other. What happens at the surface? Air has moved away from the equatorial column so there is less air above the surface so the pressure is lower. In the other column, more air has moved into the upper parts so the pressure at the surface is higher. At the surface, the air will flow from the higher pressure towards the lower pressure. This completes the circuit. Air rises at the equator, moves towards the poles, sinks back to earth and moves back towards the equator. The characteristics of low pressure systems, therefore are air flowing in at the surface, rising at the centre and flowing out at the top. High pressure systems are reversed. Air flows in at the top, descends and flows out at the bottom.

You may have noticed that I have been carefully avoiding any mention of the Coriolis effect. The earth rotates on its axis, one revolution per day. Because of this, anything moving over the surface of the earth is deflected to the left in the southern hemisphere and to the right in the northern hemisphere. The effect is weak but strongest at the poles. I will leave the ramifications of Coriolis and water going down plugholes to another time but one of the effects of Coriolis is to position the high pressure systems such that the air rising at the equator sinks back to earth between 30° and 40° south or north depending on the time of year. This belt of high pressure around the globe in both hemispheres is called the Sub-Tropical Ridge.

Because the air in high pressure systems is descending, it is very stable. Cloud will not form and without cloud there is no rain. All the world's major deserts, apart from the polar deserts, lie under the sub-tropical ridge in both hemispheres.

The other effect of Coriolis is to deflect the air blowing into the lows and out from the highs. In the southern hemisphere, the air will spiral clockwise into a low and anti-clockwise out of a high. The reverse is true in the northern hemisphere.

Answer 2

hi "D" nicely i wager you printed this question the day handed by, yep the solar change into shining her in North Wales, it change right into a good looking day, yet today!!!!! this is lower back to accepted, rain rain rain! in no way thoughts, we are able to consistently wish for further effective climate, and without the uncertainty, what might want to we British ought to communicate about?

Answer 3

go and refer an encyclopedia or a good website. no body can explain your big question. if we answer, the senders have to research a lot

Answer 4

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