강우관측소의 설치고도를 고려한 강우관측망 평가방안

The observed rainfall may be different along with the altitude of rain gauge, resulting in the fact that the characteristics ofrainfall events occurred in urban or mountainous areas are different. Due to the mountainous effects, in higher altitude, theuncertainty involved in the rainfall observation gets higher so that the density of rain gauges should be more dense.
Basically, a methodology for the rain gauge network evaluation, considering this altitude effect of rain gauges can accountfor the mountainous effects and becomes an important step for forecasting flash flood and calibrating of the radar rainfall.
For this reason, in this study, we suggest a methodology for rain gauge network evaluation with consideration of the raingauge’s altitude. To explore the density of rain gauges at each level of altitude, the Equal-Altitude-Ratio of the density ofrain gauges, which is based on the fixed amount of elevation and the Equal-Area-Ratio of the density of rain gauges, whichis based on the fixed amount of basin area are designed. After these two methods are applied to a real watershed, it isfound that the Equal-Area-Ratio generates better results for evaluation of a rain gauge network with consideration of raingauge’s altitude than the Equal-Altitude-Ratio does. In addition, for comparison between the soundness of rain gaugenetworks in other watersheds, the Coefficient of Variation (CV) of the rain gauge density by the Equal-Area-Ratio is servedas the index for the evenness of the distribution of the rain gauge’s altitude. The suggested method is applied to the fivelarge watersheds in Korea and it is found that rain gauges installed in a watershed having less value of the CV showsmore evenly distributed than the ones in a watershed having higher value of the CV.