AQA GCSE Geography - Depressions and Anticyclones

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In the above topic, I'm supposed to learn a table about the sequence of weather conditions that happen when a depressiong comes overhead. (The rain, kind of clouds, pressure etc.)

For example, Ahead of a warm front:

No rain, high thin clouds, falling pressure, low temp and increasing wind speed

 Does anyone else do AQA and have to do the same? Do you know a good technique for actually remembering it??? I'll look at the revision notes, if I find anything helpful then plz ignore this, and I'll link it if anyonw want to know where to find it (If it exists!). Any advice is appreciated :)

Posted Tue 7th June, 2011 @ 18:07 by Shaimaa

2 Answers

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i can't help you with that that question specifically but i do have some geog resources up for tectonics, coastal zone and rocks and landscapes if those help with your other units :)

Answered Tue 7th June, 2011 @ 19:04 by Chloe Thorn
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  1. At the warm front, lighter, warmer air from the south (tropical maritime air) meets cooler air from the north (polar maritime air) and rises gradually over it.
  2. As the warm air slowly rises it cools, its water content condenses and clouds form (nimbostratusthenaltostratus). The result is steady rain, later giving way to drizzle and finally clearer skies with highcirrusclouds.
  3. Behind the warm front is an area of warm, rising air and low pressure - the centre of the low-pressure system. As this part of the depression passes over, there may be a short period of clear, dry weather. However, at the trailing cold front, heavier, cooler air meets the warm air at the centre of the depression, undercutting it and forcing it steeply upwards. Quickly moving air masses produce high winds and cooler temperatures...
  4. As the rapidly rising warm air cools, its water condenses and clouds form (cumulonimbus, thencumulus). The result is heavy rain or thunderstorms, giving way to showers and finally to clear skies as the cold front moves away eastwards.

Anticyclones are the opposite of depressions – they are an area of highatmospheric pressure where the air is sinking.

As the air is sinking, not rising, no clouds or rain are formed. This is because as the air sinks it warms - meaning it can hold more water.

  1. The absence of fronts means winds may be very light.
  2. Consequently, high-pressure areas are often associated with settled, dry and bright conditions.
  3. In summer, anticyclones bring dry, hot weather. In winter, clear skies may bring cold nights and frost.
  4. In cold conditions, anticyclones may also bring fog and mist. This is because the cold forces moisture in the air to condense at low altitudes.
Answered Tue 7th June, 2011 @ 19:06 by Christopher Cartwright