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Old 7th July 2004 | 09:04
  #15 (permalink)  
Papa Bravo Delta
 
Joined: May 2004
Posts: 23
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From: Sutton, Surrey
Thanks for all the replies.

That has given me a few pointers and things to try.

I have been up until 1am two nights in a row studying this stuff (about 4 to 5 hours an evening) and here is a good example of why I am struggling. Can anyone help?

A practice question I came across was:

The dewpoint temperature of air mass is 16 degrees Celsius. At what height would you expect the cloud base to form if the surface temperature is 20.5 degrees Celsius?
A 1500 ft
B 2500 ft
C 6000 ft
D 10500 ft

Appartently the answer is A, but I answered B and can't understand why I am wrong. My reasoning is:

The surface temperature is 20.5 degrees and the dew point is 16 degrees which is 4.5 degrees lower than the surface temperature. Assuming that the ISA temprature lapse rate of 1.98 degrees per 1000 feet applies then the cloud will develop at 4.5/1.98 x 1000 = 2273. The closest answer therefore being B.

Can someone explain why the correct answer is A?
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