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Why Are Deserts Very Hot In the Day, But Very Cold In the Night?

  1. ngureco profile image83
    ngurecoposted 8 years ago

    Why Are Deserts Very Hot In the Day, But Very Cold In the Night?

  2. EFPotter profile image61
    EFPotterposted 8 years ago

    It has to do a lot with cloud cover, and head capacity.

    During the day, when the sun beats down without anything blocking it, the sand absorbs the heat and holds onto it, so that heat is radiating both from the ground and from the sun--it's like a convection oven.

    Good absorbers are also good radiators however. After the sun goes down, the sand quickly loses all of the heat that it gained during the day. Without clouds overhead to keep the heat in, it dissipates, leaving the desert very very cold.

  3. profile image49
    zducoteposted 8 years ago

    Well when the sun goes down the heat is gone which means the cold air is coming in.

  4. profile image0
    The Weathermanposted 6 years ago

    It is a combination of very dry air, terrestrial effects as EFPotter discussed, and a diurnal effect that generally produces a high pressure during heating hours and a low pressure during cooling hours. They are commonly know as "thermal" His and Lows.  Really one could look at the thermal pressure changes as a result of the temperature changing.  But as it occurs, it in turn allows for accelerated heat loss.

    Dry air heats and cools much faster than moist air.  This is because once the air temperature reaches the dewpoint, condensation MUST begin for the temperature to fall any lower.  The water in the air must begin releasing latent heat to do this.

    So, if you are in an area like the desert that usually has a dewpoint well below the temperature (very dry air) the heat is free to go for a good while before condensation must begin.

 
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