Proposal of a new rainfall product using modified weather radar data published by the Thai Meteorological Department and its application: a case study in Thailand

Abstract

Weather radar can observe rainfall over wide areas with higher spatial and temporal resolution than other observation methods. The Thai Meteorological Department (TMD) has installed ground rainfall stations throughout Thailand to monitor rainfall but the number of these stations is insufficient. The TMD has also installed weather radar systems but their data quality is deficient due to frequent spatiotemporal errors. In this study, we evaluate the usefulness of TMD weather radar data that include spatiotemporal errors and propose a new spatiotemporal interpolation method to address the problem of missing data. A new hybrid rainfall product for runoff analysis was constructed through the temporal interpolation of radar data based on substituting ground rainfall data for missing data and the spatial interpolation of data based on inverse distance weighting. Runoff analyses showed that the hybrid rainfall product reproduced the observed discharge more accurately than ground rainfall data, demonstrating the high applicability of the proposed product.