Spatial Analysis of Air Temperature in the Qinghai-Tibet Plateau

Abstract

The mapping of air temperature in the Qinghai-Tibet Plateau is of practical importance because the meteorological stations are sparse and unevenly distributed in the region. The spatial interpolation methods of inverse distance weight, ordinary kriging, ordinary cokriging, and a combined method were used to estimate the spatial distribution of the 1961–1990 January mean air temperature in the Qinghai-Tibet Plateau. The combined method is a combination of ordinary kriging and correction of altitude effect by using lapse rate of air temperature. Comparison of results showed that the problem of mapping air temperature in the Qinghai-Tibet Plateau cannot be resolved by the simple geometric interpolation method as the inverse distance weight. Ordinary kriging can manifest some spatial pattern but the performance was not improved too much. Cokriging to a certain extent was an improvement of kriging but due to the limited altitude information included in the co-variable, the interpolation results were also not in agreement with the actual situation. The combined method was superior to the other methods. The interpolation result from it was reasonable, proved by both the subjective analysis and by many previous works. The comparison of the four methods leads to the conclusion that for regions with sparse meteorological stations, such as the Qinghai-Tibet Plateau, stochastic interpolation methods must be combined with the altitude-effect correction for estimating the spatial distribution of climatic variables.