On quality of radar rainfall with respect to temporal and spatial resolution for application to urban areas

Abstract

In this study the quality of radar rainfall with respect to temporal and spatial resolution was examined. Gwangdeoksan Radar and the Korea Institute of Civil Engineering and Building Technology (KICT) Radar were used for this purpose, along with the automatic weather systems data within Seoul. In addition, several quantitative quality measures were applied to examine the resolution. A negative bias of more than 40% in the radar rainfall of Gwangdeoksan Radar occurred with changes in the temporal and spatial resolution. However, the negative bias in the radar rainfall of KICT Radar was less than 10%. The mean square error in the radar rainfall of Gwangdeoksan Radar ranged from 5.5 to 0.4 mm(2) h(-2) and the mean square error in the radar rainfall of KICT Radar ranged from 30.2 to 1.5 mm(2) h(-2). The correlation co-efficient of the accumulated time of 30 min was more than 0.7, which increased by 30% from the correlation co-efficient of the accumulated time of 10 min. The bias in the radar rainfall of Gwangdeoksan Radar was still large with changes in the temporal and spatial resolution. However, the radar rainfall of KICT Radar was quantitatively similar to the gauge rainfall, and so the radar rainfall did not need any further quantitative correction.