Proceedings with Extended Abstracts (single PDF file) - Radio ...

one-minute Z values determined from two disdrometers located one-meter apart at WallopsIsland, Virginia (Dr. Ali Tokay, JCET/ University of Maryland, Baltimore County kindlyprovided this data set). The data were taken in fairly high winds. Although the superimposedtime series from the two disdrometers agree rather well as far as gross trend, the closeexamination of the differences between the observed Z values shows that one minute valuesare actually quite noisy, with some simultaneous observations disagreeing by 10 dBZ or so.Nonetheless, the nearly half-day average-difference converges nicely towards zero.Figure 2 Left: Comparison of 12 hours of Z values from two disdrometers placed 1meter apart at Wallops Island, Virginia. Right: Comparison of 1 hour of Z values observedfrom two colocated profilers during LBA. The tick marks are 10 dBZ apart, with thehorizontal line at 0 dBZ. The dots around this line represent the difference between thesimultaneous observations.Performing the same exercise, we see in Figure 2 Right that the 915 and 2835 MHzprofilers also agree nicely in gross trend. Relative to the disdrometer figure, the smallerscatter shown in the difference plot for the two profilers may be partly due to the largervolumes sampled. However, no firm conclusion should be drawn because the locations andtimes of the two comparisons are very different. In this case, the statistical fluctuations in theprofiler Z difference values are small enough that the enhancing effect of clear-air scatter iseasily seen for Z values below, say, 15 dBZ.Figure 3: Scatter plots of (top) Z 2835 vs. Z JWD and (bottom) Z 2835 -Z JWD vs. Z JWD .Both axes range from 0 to 60 dBZ in 10 dBZ increments. The data represent 39days of LBA observations.363