垂直干旱指数在高寒农区春旱监测中的应用研究

Application Research of Perpendicular Drought Index for Spring Drought Monitoring in High and Cold Agricultural Area

青海省东部农业区"十年九旱"、"春旱年年有",对农业生产的影响非常严重,但该地区至今缺乏有效的春季干旱遥感监测方法。使用环境减灾卫星CCD数据提取青海省东部农业区农业气象观测站的垂直干旱指数(PDI),拟合其与不同深度土壤水分的关系模型,各模型的无偏相关系数均在0.7以上;其中PDI与0~20cm土壤相对湿度关系模型(y=-489.00x+188.78)的拟合效果最好(无偏相关系数为0.7985)。该模型反演的湟源农业气象观测站固定观测地段的土壤水分时间变化序列与人工测量值的时间变化序列,在趋势变化上较为一致。2013年西宁农区的春季干旱监测中,该模型监测结果显示:发生干旱的地区主要出现在大通河谷地和湟水谷地,湟源农区的土壤旱情在整个西宁农区的土壤旱情发展中最为严重,监测结果与实际旱情分布地区一致。

Drought,especially spring drought,prevails almost every year in the eastern region of Qinghai.It had a great impact on agriculture,while lacking of an effective remote sensing monitoring method.The values of Perpendicular Drought Index(PDI)of the agricultural meteorological stations,which were extracted from HJ-CCD,fitted relationship among soil moisture of different depth,their unbiased correlation coefficients(R*)were all above 0.7.Especially,the relationship at the depth of 0~20cm(y=-489.00x+188.78)was best(R*=0.7985).And it was used for the soil moisture inversion on the fixed period of Huangyuan agricultural meteorological station,the result showed that the time series trend of soil moisture from remote sensing inversion and manual measurement were similar.And this method was used to monitor the Spring Drought on Xining agricultural region of Qinghai in 2013.It showed that the drought regions were mainly distributed in the river valley of Datong and Huangshui,the drought of Huangyuan was the most serious,it was comparatively unanimous to develop with the real drought.