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## calculate freezing level?

• Nicholaspryzibilla
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### Nicholaspryzibilla created the topic: calculate freezing level?

Hi,
In the BOB TAIT CPL MET theory book, I've been going through some of the practice questions.
Exercise GM 3 question no. 11 asks.

Cumulus cloud with a base of 3000ft above the ground is observed over an aerodrome. If the elevation of the aerodrome is 2000ft AMSL and the air temperature at ground level is 18degreesC, at approximately what height would the freezing level be expected inside the cloud?
The answer in the book is [D] 11000ft AMSL

I cannot get the same answer no matter how many times I try.
do you count ground level as aerodrome level? same is in a TAF in regard to cloud height.
in the working out provide it seems not. I'm extremely confused and have my CASA MET exam TOMMOROW. up until this point I was getting all my sums correct on this topic at the ground school I attend.

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### bobtait replied the topic: calculate freezing level?

From sea level to the cloud base, the rising air cools at the DALR (3°/1000ft). From the cloud base to FZL the rising air cools at 1.5/1000ft (SALR). Temperature at the cloud base is 9° (18 - 3x3). Lose another 9° at 1.5°/1000 = 6000ft. FLZ = 11000ft.

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