CORRECTION OF XRAIN PRECIPITATION INTENSITY USING 1-MINUTE RAIN GAUGE DATA

Abstract

 In a previous study, the authors developed a method for estimating 1-minute precipitation intensity from JMA rain gauge data. The previous method estimates the time of a tipping and calculates the precipitation intensity, assuming that the precipitation intensity between tippings is constant. In this study, the method was improved to estimate the change in precipitation intensity between tippings by referring to the XRAIN. Compared to the previous method, the accuracy was improved. Next, the correction coefficients are determined by viewing this as a correction to XRAIN. The correction coefficients were moving averaged in time and spatially interpolated to correct XRAIN in the absence of rain gauges, and it was found that it is better to set the confidence level of XRAIN according to the distance from the radar and the time scale of smoothing according to the distance from the rain gauge. The accuracy is generally improved compared to XRAIN before correction, but strong rainfall such as linear precipitation zones are underestimated.