巴彦淖尔市干旱指数变化规律和草原退化原因

采用巴彦淖尔市4个牧业旗县气象站40a（30a）的关键时段平均气温和降水量资料，计算逐年干旱指数，由各站干旱指数来评定草原旱涝程度，并依此评判逐年牧草长势，分析其变化规律.结果表明，随着气候逐渐变暖，干旱指数呈增大趋势，即草原干旱呈加重趋势。气候干旱是引起草原沙化的主要因素之一，据此提出了防止草原退化的建议。

Study on Variation of Drought Index and Causes of Grassland Degradation in Bayannaoer Area

The degree of drought cannot only be judged by a deficit of precipitation,but also temperature variation affecting the evaporation,soil moisture.Based on the 40a mean temperature and precipitation data of 4 meteorological stations during the key stages of plant-growing,annual drought index(DI) was calculated so as to evaluate the drought/flood degree of the grassland in Bayannaoer area.Taked the variation of the plant-growing and the climate change factor into account,a result of drought index(DI) increasing tendency was indicated,meaning that grassland drought is becoming more severe than before.Besides the climate factor,man producing action also contributed to the grassland desertation.Based on the analysis,some countermeasures were proposed to prevent grassland desertation process.