Re: What were you guys smoking....

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Posted by Harold Ericsson on October 20, 2002 at 18:34:23:

In Reply to: Re: What were you guys smoking.... posted by Mark Holloway (Tumbleweed) on October 19, 2002 at 04:45:09:

There are certainly complexities involved in any attempt to compute the evaporation rate of a body of water while wind is creating waves and in turn the waves create air turbulence that would affect the relative humidity of the air over the body of water under study.
I have seen two numbers for the annual rate of evaporation in Death Valley, one is 125 inches per year and another is 150 inches. I have a memory of 185 inches for a year as a given number for the evaporation rate in Death Valley but I have been unable to find that number, in any case, in viewing a number of Death Valley sites it seems that evaporation studies are being made at the present time.
There may be a solution to this pressing problem of water evaporation under windy conditions. The inflow and outflow of water to and from Lake Isabella plus the total drop in the amount of water in the lake can be found at It should be noted the outflow minus the inflow does not equal the loss of water to the lake. The site also gives the daily evaporation rate as measured from an EVP that I assume is a class A U.S. National Weather Service evaporation pan and I also assume that the difference between total lake loss and outflow minus inflow is due to evaporation. Interestingly, the evaporation pan comes equipped with an anemometer along with the expected maximum and minimum thermometer. The class A pan that Iím looking at in Ben Meadow Companyís marvelous catalog has a diameter of 47.5 inches, not a reach that would allow waves of size to form. If the rate of evaporation could be correlated with observed and measured wind conditions plus the amount of water loss to the lake we might have an answer to our problem.

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