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<br /> <br />uming to the three Denver gages and one snow board in table 5, site 7 (manned 24 hours per day) had <br />e most hours of observations. However, 97 of the 198 hours with recorded SWE had trace observations, <br />hich were assumed to be 0.003 inch for the purpose of calculation. If only the 101 hours with site 7 <br />o servations of 0.01 inch or more are considered, the R value is reduced to 0.60 at this exposed location. <br /> <br />ptimized results from the four Denver sampling sites or combinations of them show P values near 2.0 <br />e cep for Denver's gage 3. The large gage 3 P value of 2.7 is likely related to its insensitive CTF as <br />d scussed in section 3.2. Exponents for all other sites of table 5 ranged only between 1.9 and 2.3. <br /> <br />ased on the results presented here and cited publications, a P value of 2.0 is recommended for use at <br />b th Cleveland and Denver. Little evidence currently exists to indicate that a value much different than <br />2 0 is suitable for snowfall. <br /> <br /> <br />ing to the avalues, considerable consistency is seen with only 100 to 151 pairs at the three Denver <br />grges. The single snow board site has an optimized a value of 199, possibly related to the high <br />Prrcentage of trace observations and limited protection from wind effects. Nevertheless, its a value is <br />n t greatly above the range of 127 to 161 for the three gages. With the uncertainties in the CTF curves <br />f, r Denver's gage 3 and limited protection from the wind at site 7, the optimized values for combined <br />g ges 1 and 2 appear most appropriate for the Denver area. That is, the a value is recommended to be <br />1 0 and the p value 2.0. Very similar values are seen to result from combining sites 1, 2, 3, and 7. <br /> <br />F gure 2 is a plot of the two recommended Ze-S relations for Cleveland and Denver, respectively. The <br />fi e shows that any given snowfall rate produces a higher reflectivity at Cleveland than at Denver. The <br />d fference can be expressed as 3.4 dBZ so, for example, a snowfall rate of 0.020 inch h-I produces 15.9 <br />d Z at Denver but 19.3 dBZ at Cleveland. This difference is substantially larger than expected from any <br />c ibration errors because the calibration checks are supposed to maintain a reflectivity precision of 1 dB <br />( unter, 1996). However, radar calibration may be a problem at some locations as reported by Smith et <br />. (1996). Checking radar calibrations is beyond the scope of the SAA development work, so level II <br />d ta must be assumed to be correct unless special calibrations are done. <br /> <br />5 10 15 20 25 30 35 40 <br /> <br />Recommended Ze-S Relations <br />for Denver Area (upper curve) <br />and Cleveland Area (lower curve) <br /> <br /> <br />7 <br /> <br />6 <br /> <br />5 <br /> <br />"""" <br />.c <br />"'- <br />4E <br />E <br />"-" <br /> <br />3 <br /> <br />2 <br /> <br />~oo 0 <br />o 5 10 15 20 25 30 35 40 <br />Ze (dBZ) <br /> <br />F gure 2. - Plots of recommended 28-5 relationships for Cleveland (lower curve) and Denver (upper curve) areas. <br /> <br />14 <br />