章古台沙地降水变化及干燥度指数分析

摘要

Meteorological data of Zhanggutai region from 1983 to 2010 were analyzed.The average annual rainfall is 469.4 mm,the maximum value is 689.2 mm and the minimum is 285.9 mm,furthermore rainfall mainly concentrated in June,July August;July is the highest.Precipitation is not only the main factor which affects the water table,but also the main limiting factor of local vegetation.In recent 28 years,de Martonne dryness index of Zhanggutai region ranges between 16.7 and 43.1,average value being 28.2;Kira dryness index ranges from 2.8 to 7.1,mean value being 4.6,and that Rhythm dryness index ranges from 0.8 to 2.1,average value being 1.3;de Martonne dryness index and Kira dryness index tend to decrease;rhythm dryness index tends to increase;local climate becomes dry and severe.According to three dryness indices,Zhanggutai is a typical sub-humid arid area;semimoist composition is more than semiarid ingredients.Consequently,meadow steppe,forest steppe,woodland and grassland should be the major trends of local vegetation and ecological restoration.%通过对章古台地区1983—2010年间气象数据统计分析,结果表明,章古台地区年平均降水量469.4 mm,最大值689.2 mm,最小值285.9 mm,降水主要集中在6、7、8月,7月最高。降水量是影响地下水位的主要因子,是当地植被建设的主要限制因子。28年来,章古台地区de Martonne干燥度指数区间16.7～43.1,平均值28.2;Kira干燥度指数区间2.8～7.1,平均值4.6;谢氏干燥度指数区间0.8～2.1,平均值1.3;de Martonne干燥度指数和Kira干燥度指数有降低趋势,谢氏干燥度指数有升高趋势,当地气候有变干旱、变恶劣的趋势。根据3种干燥度表达值,章古台地区是典型的亚湿润干旱区,半湿润成分偏多,半干旱成分偏少。当地植被建设和生态修复应向草甸草原、森林草原、疏林草原方向发展。