WMOD00574

• Title: Studies of Wintertime Storms Over the Tushar Mountains in Utah
• Date: 3/1/1986
• State: UT
• Country: United States
• Weather Modification - Doc Type: Report

6

II. ESTIMATE OF MAXIMUM POSSIBLE WEATHER MODIFICATION EFFECT

In this Chapter, an estimate of the total mqss of liquid water
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which passes over the Tushar range, but is not utilized in the

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precipitation process, is determined by integrating radiometer data and

rawinsonde winds during each storm. Two assumptions were necessary to
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perform these calculations:

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, ~ ~/b- t...vA
~"c.-" VrW ,~
'v),) Ql.."c~~~
~ \.11\~1
'?Q,~~\ 0 ~.I 2.

....--.--....""'-c.._.._ .'-

representative of those aiong the crest of the mountain over

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the region where seeding would be effect~ve (assumed in these

calculations to be SO km in north-south extent).

The cross-barrier component of the 700 mb wind speed is

representative of the speed at which all of the liquid is

passing over the mountain.

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The approach used was to determine the average liquid water

- ,.-' -- - ---...:=----

measured by the radiometer over a three-hour period centered on the

launch time of each project rawinsonde. Since the radiometer was
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operated in two modes (zenith and scanning), an averaging scheme which
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accounted for both modes had to be developed. The averaging was done in

the following way:

1. For each project variable, the radiometer data were checked for

data availability. If radiometer data were available for.~~y

p~~ of the three-hour period centered On the rawinsonde launch

time, the data were used in the calculations.

2. The radiometer scanning data were normalized to the vertical.

3. The radiometer mean liquid water depth for the three-hour

period was determined by the following equation:

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