Radiation, soil texture, and water

[Steve Bousquin]

I am looking for a way to combine solar radiation at a site with soil
texture classes into a model that will give an index-type estimate
(i.e., relative values -- like high to low) of water lost to
evaporation, or lost to a combination of evaporation and percolation.  I
am trying to rank sites by these factors according to water remaining or
water lost or water available after a rainfall in an arid system.

If  you know of such a model or have any ideas, please respond as email
in addition to posting.  Thanks!

--
Steve
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