The variation tendency of surface aridity index of Shanxi province in recent 50 years

To investigate the variation tendency of surface aridity index from 1960—2010 in Shanxi province,the region was divided into six climatic zones based on the climatic data of 39 meteorological stations and topography. A ratio of potential- evapotranspiration to precipitation was employed as the aridity index and its distribution was further created through the IDW method. The results show that the area of Shanxi belonged to a semi-arid area and the average aridity index was 2. 21. The spatial distribution of mean annual aridity index was closely related to climate,topography and other factors,whereas differed significantly from north to south. Generally speaking,northern and central regions of Shanxi province were relatively dry( the aridity index was 2. 36),and southern and eastern regions were humid( the aridity index was 2. 36). In recent 50 years,the slight increase in the aridity index( as little as 0. 04·10a- 1) was attributed to reductions of both precipitation and potential- evapotranspiration,resulting in insignificant drought trend. It was further found that drought conditions had eased in the northern Shanxi,while became more severe in other areas. Additionally,drought conditions in Shanxi province varied in different seasons,humid in summer and fall and very dry in winter and spring. Therefore,it was concluded that climatic warming had not aggravated surface aridity in Shanxi province in recent 50 years. However,the climatic tendency of warming and drying should bring up enough attentions.