ON THE INTERPOLATION OF HYDROLOGIC VARIABLES - FORMAL EQUIVALENCE OF MULTIQUADRATIC SURFACE FITTING AND KRIGING

The paper focuses on the ties of kriging with a deterministic interpol ation procedure, known as multiquadratic surface fitting. The two meth ods are compared, first from a theoretical point of view, then using a practical example. It is shown that kriging equations with a linear v ariogram model are identical in form to equations of multiquadratic su rface fitting with cone surfaces. The issue of the accuracy of both es timators is discussed through a case study where hourly rainfall maps of real storm events collected by radar provided the reference rainfal l. Random point sampling of the accumulation pattern simulated gauge r eturns. Eight sampling densities were used and for each density rainfa ll spatial distributions were estimated for a large number of realisat ions. It is shown that kriging performs better at lower gauge density, while at higher gauge density the accuracy of both estimators is simi lar.