Ask A Scientist© Weather Archive

 
 >   name        mike
 >   status      student
 >   age         20s
 >   EMAIL
 >   Question -  why does in rain in the arid zone?


>Dear Mike-
>
>   "Arid" or "desert" type climates generally describe areas that receive
>less than 25 cm of precipitation a year. There are very few places that go a
>whole year without any precipitation...but some isolated desert locations
>may go several years without rain. Precipitation is dependent on several
>factors, including location relative to the general global circulation,
>elevation, latitude, and proximity to certain geologic features, such as
>mountains and oceans.
>
>So, most arid regions will receive some precipitation each year, but much
>less than moist regions.
>
>Wendell Bechtold, meteorologist
>Forecaster, National Weather Service
>Weather Forecast Office, St. Louis, MO.

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>Even desert areas receive some rain, although the moisture comes from
a
  >non-arid area. A good example is the little amount of rain that falls
  >in the western deserts of the United States; most of the moisture
comes
  >from the Pacific Ocean, but little is left after orographic lifting
  >causes most of it to fall in the mountains of eastern California.
  >
  >David Cook 
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