关键词: 水热资源, 西北干旱区, 中国西北地区, 湿润指数, 距平, 干燥程度, 气候区划, 年平均, 干燥度, 月平均

Abstract: In this paper, the aridity index (K') and the radiational index of dryness (D) are used to show the extent of dryness in the Northwestern part and to make division of arid climate, It is useful to do so for understanding the structure and distribution of the arid climate, in Northwestern The mean monthly aridity index and the anomaly per cent of the moisture index (S%) are used to analysed the dynamics of dry and wet variation in a year and the rhythm revolution of the dry years, It is advantageous to do so for comprehending the total trend of the drought variation. In order to use the hydrothermal resources rationally in the North west arid area, an equation, from the viewpoint of the rational evapotranspiration (E_0.4), the depth of the rational irrigation (G_0.4) and the standard of the rational irrigation (Q_0.4), is presented through the actual evapotranspiration (AE) the Bawen ratio (β) and the net radiation (Rt) from the viewpoint of the regulation of the hydrothermal resources.