WMOD00546

• Project Name: High Plains Cooperative Program
• Title: On the Sampling Variance of Raingage Networks
• Weather Modification - Doc Type: Report

6. Comparison with previous studies

We now compare the results of this study with those of other investigators
who have considered this problem. As stated earlier, previous investigators
(Light 2; Linsley and Kohler, 1951; McGuinness, 1963; Huff, 1970; INoodley
et al., 1975) defined the averaqe error in determining areal mean rainfall as
the difference in rainfall calculated from their highest gage density,
assumed to be the "true" rai nfall, and that cal cul ated from subneblOrks of
lesser density. They related tlhese errors to some or all of the following
parameters: mean precipitation, gage density, area, and storm duration.
There are two points to be considered in light of the results of this study,
namely the accuracy of their assumed "true" rainfall and the meaning and
utility of the empirical sampling error relationships.

Light derived his empirical relationship for areas in the range of 500 to
8,000 mi2 with a primary gage density of 18 mi2 per gage. Linsley and
Kohler derived their error relationship for a fixed area of 220 mi:~ and
a basic gage dens ity of 4 mi 2 pE~r gage. McGui nness used data from a
7.16 mi2 watershed having a gagE~ density of 0.11 mi2 per gage to derive
his mean rainfall accuracy exprE~ssion. Huff derived his comprehensive error
function with data from gage networks covering 400 and 550 mi2 haviing gage
densities of 8 and 11 mi2 per gCl'~e, respectively. Woodley et ale (1975)
derived their error curves for elln area of 220 mi2 having a gage density of
1.18 mi2 per gage. The maximum 9age densities used by these investigators
were examined in the context of Eq. (2). The coefficient of variation for
the 1 argest number of gages per storm (maximum gage dens ity for the area
gaged) and the precipitation gradient of the storms (Table 2) considered in

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