ON THE CHOICE OF SPATIAL INTERPOLATION METHOD FOR THE ESTIMATION OF 1-TO 5- DAY BASIN AVERAGE DESIGN PRECIPITATION

摘要

The aim of the study was to derive frequency curves of annual maximum basin average of 1-to 5- day precipitation depths for the upper Hron River basin. Three spatial interpolation schemes were selected for the analysis. The Thiessen polygon method and the inverse distance method gave systematically lower values for shorter durations of precipitation then the altitudinal zones method; most probably due to the fact, that convective precipitation can play a significant role in annual maximum daily precipitation values. For longer durations all methods gave comparable results. The inverse distance method has a better potential to reflect and project the actual spatial distribution of daily measured data into the spatially interpolated rainfall surface than the Thiessen polygon method, since the measurements reflect altitudinal zonality as well. Co-kriging, which can included the effect of topography, could probably also provide accurate and realistic estimates, but its application is tedious when compared with the inverse distance method. This method can be therefore recommended as an appropriate interpolation scheme for engineering applications.