Application Analysis of Radar Polygon Method

Abstract

This study proposed the new spatial interpolation of precipitation method, for areal rainfall estimation based on radar precipitation data. We named this methodology “the Radar Polygon Method” (RPM). In this approach, gages in the study area compete against each other to gain the grid cells of the radar precipitation field under its territory. The criterion of the competition between the gages is the similarity between the precipitation of the target grid cell and that of the gage location. RPM method was applied to determine the weight factor of the four watersheds in Korean Peninsula in which 41 rain gage locations. Even though RPM uses only the information regarding the spatial variability of rainfall extracted from the radar rainfall imageries without any geographical information, it obtains the polygon-like (or just polygon) shape of the governing territory for each of the gages in all four study watersheds. This study suggests new application fields of radar data of which use has been limited due to short observation period and low accuracy. The RPM provides an original way of using operational radar rainfall data for areal rainfall estimation that maintains the simplicity of Thiessen polygon approach.