A COMPARATIVE ANALYSIS OF TECHNIQUES FOR SPATIAL INTERPOLATION OF PRECIPITATION¹

TLDR

Spatial interpolation is routinely employed in hydrology to estimate missing or ungaged precipitation data, and numerous techniques of varying complexity are available. This study compares the applicability of several interpolation methods for estimating annual precipitation at selected sites. Using thirty years of annual precipitation records from 29 stations in Region II of the North Central United States, the authors evaluated the error of Thiessen, polynomial, inverse distance, multiquadric, optimal interpolation, and Kriging techniques at five test sites. Kriging and optimal interpolation performed best, with multiquadric nearly as good, while inverse distance and Thiessen were satisfactory and polynomial performed poorly.

Abstract

ABSTRACT One of the problems which often arises in engineering hydrology is to estimate data at a given site because either the data are missing or the site is ungaged. Such estimates can be made by spatial interpolation of data available at other sites. A number of spatial interpolation techniques are available today with varying degrees of complexity. It is the intent of this paper to compare the applicability of various proposed interpolation techniques for estimating annual precipitation at selected sites. The interpolation techniques analyzed include the commonly used Thiessen polygon, the classical polynomial interpolation by least‐squares or Lagrange approach, the inverse distance technique, the multiquadric interpolation, the optimal interpolation and the Kriging technique. Thirty years of annual precipitation data at 29 stations located in the Region II of the North Central continental United States have been used for this study. The comparison is based on the error of estimates obtained at five selected sites. Results indicate that the Kriging and optimal interpolation techniques are superior to the other techniques. However, the multiquadric technique is almost as good as those two. The inverse distance interpolation and the Thiessen polygon gave fairly satisfactory results while the polynomial interpolation did not produce good results.