Why is Antarctica's cold climate responsible for its very low amount of yearly precipitation?

1 Answer
Apr 28, 2016

The amount of water vapor that the atmosphere can hold is dependent on the temperature.

Explanation:

Water can exist in vapor form at temperatures much cooler than the boiling point. In fact right up to about -40 there can be water vapor in the air. However the amount of water vapor that the air can hold is entirely dependent on the temperature. So in areas with very cold climate like the Antarctic and the Arctic, we end up having snow covered deserts because there is never enough water in the air to form much precipitation.

enter image source here

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On this graph the red line shows the maximum amount of water vapor the air can hold at any given temperature. You can see that at 15 degrees C the air can hold about 10g of water vapor per kg of air. At -20 the amount is right around 1g /kg.