Areal rainfall estimation using spatial interpolation techniques

摘要

Accuracy in runoff and flood estimation is important for mitigating water related problems. The accuracydepends on the methods used for areal rainfall approximation. The thin plate spline (TPS) technique was introduced in thisstudy for daily areal rainfall approximation in the Upper Ping river basin and was compared with the areal rainfall estimatedfrom two conventional techniques, the isohyetal and Thiessen polygon techniques. Two data sets of maximum rainfallregistered in August 2001 and September 2003 at 68 non-automatic rainfall stations located in the basin and nearby areaswere used in the analysis. The TPS technique was carried out in conjunction with two separate sources of digital elevationmodel (DEM), namely, GLOBE-DEM and SRTM-DEM, which were downloaded from the NOAA and NASA websites andhave horizontal resolutions of 1 km and 90 m, respectively. The TPS technique proved to provide more accurate results ofrainfall estimation than the other two techniques. The coarser DEM resolution (GLOBE-DEM) performed marginally betterin rainfall estimation than the finer DEM resolution (SRTM-DEM).