Estimation of ArealPrecipitation using Radar Precipitation Field

Abstract

This study the Radar Spatial Interpolation Method (RSIM), RSIM is meant to determine the area of influence of rain gages located in the precipitation field of a radar. In this method, each rain gage contests with other gages in the proximity of a radar field to occupy the maximum number of radar grid cells under its area of influence. RSIM method was applied to determine the weight factor of the 17 rain gages at each of the 7 watersheds; one watershed (Ansung Stream Watershed) is relatively large compared to the remaining 6 watershed having the size of 1,649 km2. The area of the remaining watershed ranged between 60.1 km2 and 203 km2. The shape of RSIM is similar to Thiessen polygon while it does not use any geographical information but uses the information regarding the spatial variability of rainfall extracted from the radar rainfall imageries. And for the small size watershed, the areal rainfall estimated using the Thiessen polygon approach can be different from the actual rainfall when the rain gages are located far from the watershed. This study suggests new application fields of radar data of which use has been limited due to short observation period and low accuracy..