摘要
土壤水分对干旱区气候变化、生态环境稳定、绿洲农业发展有着重要的影响作用。以新疆精河流域绿洲为研究区,基于Landsat TM和ETM+影像,借助修正后的温度植被干旱指数(TVDIm),进而反演了研究区2002年和2011年春、夏、秋3季的表层土壤水分。结果表明:(1)野外同步实测数据精度验证R~2值为0.800 2,TVDIm能够较好反映绿洲土壤水分分布状况;(2)研究区表层土壤水分的季节性变化明显,即秋季>夏季>春季,近10年间土壤水分总体呈趋湿特征;(3)研究区绿洲内部的土壤水分状况明显优于过渡带及天然荒漠区;(4)土地利用叠加分析指示,人类活动对土壤水分的空间分布影响强烈。
Soil moisture has an important influence on the change of climate,the stability of ecological environment and the development of oasis farming in the arid area.Based on the Landsat TM and ETM+ images,we selected the Oasis of Jinghe Basin as the study site and investigated the moisture changes of the topsoil in spring,summer and autumn during the period from 2002 and 2011using the modified Temperature-Vegetation Dryness Index(TVDIm).The findings are listed as follows:(1)By comparing and measuring,we found that the R~2 value of precision is 0.800 2,which means that TVDIm can better reflect the distribution of soil moisture in oasis;(2)The seasonal changes of moisture in the topsoil of the study area are significant,that is to say the moisture decreased in the order:autumn>summer>spring,and the water content is becoming higher in recent 10years;(3)The condition of soil moisture in the inland of the study area is better than that in the transition belts and natural deserts;(4)The overlay analysis of land use indicated that human activities had the strong influence on the spatial distribution of soil moisture.
引文
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