Estimation of radar rainfall using radar composite techniques between the Sattahip and Rayong radar stations

Abstract

The application of radar rainfall data from a single station could contain errors and led to inaccuracy in rainfall estimation. The paper aimed to present the result of the study on the efficiency of rainfall estimation using radar composition techniques between the Sattahip and Rayong radar stations. Four radar composite techniques comprising the average (AVG), nearest distance (DIST), maximum (MAX) and weighted distance (WD) were used in this study. Reflectivity data from both radar stations and gauge rainfall data from 127 automatic rain gauge stations corresponding to 26 rainfall events in 2020 were used for the analysis. By considering all rainfall events, it was found that all composite methods produced more accurate radar rainfall estimation than the estimation from individual radar station. To this regard, the AVG method gave the best results as its increased accuracy was accounted 11.4 percent of the estimation using data from the Rayong radar station. However, the accuracy was close to the WD and DIST methods whereas the MAX method provided least accuracy. When considering the efficiency of the composite techniques based on the rainfall intensity, it was found that the MAX method apparently increased the accuracy of radar rainfall estimation, comparing with the remaining three methods. Additionally, the MAX could significantly improve the accuracy of moderate rain estimation by 28.42 percent of the estimation using Rayong radar data.