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<br />surrounding each gauge location and chooses the radar estimate closest in amount to the gauge <br /> <br />rainfall to pair with that gauge observation. The polar grid bins ofiainfall have a size of2-km in <br /> <br />range by I-deg in azimuth. These pairs are then passed into the algorithm's Kalman filter where <br /> <br />-, <br />the actual bias estimation is perfonned by combining the current hour's gauge-radar observations <br /> <br />with observations from previous hours, These steps are perfonned once every hour at H+50 <br /> <br />minutes using hourly accumulation ending at H+OO minutes. <br /> <br />Figure 8 is a log-log scatter plot of gauge-radar pairs of stonn-total rainfall for all of the <br /> <br />85 gauges within 230 km of FTG that reported rain during this event. The radar estimates have <br /> <br />not been adjusted by any computed biases in this plot. Although the PPS Adjustment algorithm <br /> <br />does not fonn or use such storm-total gauge-radar pairs, this plot illustrates several general <br /> <br />points about the process by which gauge-radar pairs are fonned for individual hours during the <br /> <br />hourly bias estimation procedure. <br /> <br />For each available stonn-total gauge observation in Fig. 8, a set of six symbols are plotted <br /> <br />corresponding to the various possible radar estimates at that gauge location. The "<" and ">" <br /> <br />symbols represent the minimum and maximum stonn-total radar estimates from the nine <br /> <br />surrounding polar I-deg by 2-km bins at each gauge location. The "+" symbol represents the <br /> <br />radar estimate in the center bin collocated with the gauge. The triangle represents the average <br /> <br />radar estimate from the nine surrounding polar grid bins. The open circle represents the radar <br /> <br />estimate closest in rainfall amount to the gauge observation from the nine surrounding bins. The <br /> <br />filled circle represents the radar estimate that the Adjustment algorithm would choose to pair <br /> <br />\\lith the gauge observation. <br /> <br />The algorithm is designed such that if the gauge observation falls within the range of <br /> <br />II <br />