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<br /> <br />.. "MP)( -. ' , , buf . <br />J :t 98111000'''' <br /> <br />'t; ';''''''2~;~ ;;-'~':,;,; , <br /> <br />"",il.."" . <br /> <br />4:: <br />]:- <br /> <br />;t <br />, ,O~r7i',lu'=lJ <br />".<lI.:O"1)CtII"', <br /> <br />.. :t~-"" " <br /> <br /> <br />"JT~"'" ., <br /> <br />, , it", , , , , , , <br /> <br />, , i J-r , , , , , , <br /> <br />.. :r""" " <br /> <br />spread. The trace-light results were good for <br />identifying unsuppressed ground clutter. The wide <br />spread results identified pixels of decreased <br />accumulations having excessive suppression <br />("holes" in pattern) and occultation problems <br />(radial bands, seen at the top offigure 8). The <br />ASCII formatted hybrid scan file could then be <br />edited by hand to correct the problems. Pro- <br />cedures for hand editing of the occultation file <br />have not been developed. <br /> <br />It was also noticed that "accumulations" <br />sometimes had anomalous propagation (AP) <br />during clear weather. Protection against AP, <br />present in the PPS (Precipitation Preprocessing <br />Subsystem), is not used in the SAA because AP is <br />rarely a problem during snow events. <br /> <br />7.3 Vertical Profile of Reflectivity <br /> <br />Arlin Super, the former manager of the project, <br />and I have repeatedly expressed our opinion that a <br />major contribution to the SAA would be to take <br />into account the vertical profile of reflectivity or of <br />precipitation. However, it was never in <br />Reclamation's scope of work to do so, even though <br />many of our studies documented the need. To <br />study the virga contamination problem, an <br />experimental SAA supplement was developed to <br />visualize the VPR. The coding changes are <br />presented in appendix A. For each hour, the <br />algorithm accumulates (at 0.1 km vertical <br />resolution, 0 to 5 km in altitude above the radar) a <br />cumulative percent of observed reflectivities at <br />5 dBZ resolution. The output is a simple 8-bit <br />array which must be imported into separate image <br />processing software and annotated there. <br /> <br />Figure 7a.-Vertical profiles for 10 November 1998. Figures 7 a-e give vertical profile examples, in the <br />same style as figure 1, for 10, 11, 16, 18, and 19, <br />November 1998, for five radars in the Dakotas and Minnesota. From left to right, they are KBIS, KABR, <br />KMVX, KMPX, KDLH. On 10-11 November, a large snow storm affected the region, moving in from the <br />southwest. Figure 7a shows profiles with strong vertical gradients, with strongest reflectivities near the <br />ground, for KBIS and KABR on 10 November 1998. The other three radars show virga as the storm <br />nears, later transforming to the precipitation graC~ent. KMPX and KDLH show some bright band effects <br />at the top of figure Th. The end of the storm on the 11th shows a transition to shallow echoes. <br /> <br />13 <br />