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corresponding unadjusted estimates. This is evident in Fig. II, In general the majority of filled circles are closer to the diagonal line than the corresponding open' circles (the latter of which nearly match the case ifno adjustment had been done), consistent with stonn-total sample biases closer to 1.0 as described previously. However, some filled circles have moved farther away from the diagonal line, implying a local degradation of the adjusted estimate. The net result is that the integrity of radar estimates are improved over the majority of the radar domain at the expense of reducing their integrity at a few locations. The current Adjustment algorithm is designed to perfonn radar-wide bias reduction by combining all gauge-radar pairs together regardless of their spatial location. Therefore it does not account for any possible spatial variability of gauge-radar biases that may exist across the radar domain due either to stonn-to-stonn variability or range-dependent variability. Spatially varying bias adjustment techniques are being examined for possible future implementation at radar sites where abundance of real-time gauge data justify their use. 6. Sensitivity of PPS estimates to the rain rate threshold Previous discussion of Table I briefly alluded to the effect of the rain rate threshold on the quantitative perfonnance of the PPS. This section will examine this sensitivity in greater detail. Three gauge-radar scatter plots of unadjusted storm-total rainfall for the. Buffalo Creek event for all gauges within 230 Ian ofFTG (Fig. 12) illustrate the impact of various rain rate thresholds on the slonn-total rainfall. The plotted symbols are defined in Table 2. Figures 12a, b, and c correspond, respectively, to stonn-total gauge-radar pairs in which the a) 3x3 center radar bin (collocated with the gauge), b) 3x3 radar average, and c) radar bin as 17 /