UNCERTAINTIES IN WSR-88D MEASUREMENTS AND THEIR IMPACTS ON MONITORINGLIFE-CYCLES

Radar measurement uncertainties associated with storm top, cloud top, and other height measurements are well recognized; however, the author s feel the resulting impacts on the trends of storm features are not a s well documented or understood by some users of the WSR-88D system. D etailed examination of radar-measured life cycles of thunderstorms occ urring in Arizona indicates substantial limitations in the WSR-88D's c apability to depict certain aspects of storm-height attribute evolutio n (i.e., life cycle) accurately. These inherent limitations are illust rated using a vertical reflectivity structure model for the life cycle of a simple, ''single-pulse'' thunderstorm. The life cycle of this si mple storm is ''scanned'' at varying ranges and translation speeds. Th e results show that radar-determined trends are often substantially di fferent from those of the model storm and that in extreme cases the ra dar-detected storm and the model storm can have trends in storm-top he ight of opposite sign. Caution is clearly required by both the operati onal and research users of some products derived from operational WSR- 88D data.