基于中分辨率成像光谱数据的塔里木河流域土壤湿度时空动态变化研究

Temporal and Spatial Dynamic Changes of Soil Moisture in the Main Stream of Tarim River Based on Mid Resolution Imaging Spectral Data

基于2010—2019年的MODIS卫星影像数据与实地调查,在地理信息技术的支持下,从宏观角度实现了塔里木河流域土壤湿度的遥感监测。研究结果表明,MODIS第7波段的反射率与土壤湿度呈负相关,塔里木河流域上、中、下游土壤湿度在年内空间上、时间上差异较大:通过同期不同河段的对比分析可知,塔里木河流域土壤湿度上游>中游>下游;同河段不同时期对比分析可知,塔里木河土壤湿度增加量表现为上游>中游>下游;塔里木河流域土壤(0~10 cm)湿度年内季节性变化较大,在2019年6月达到最大土壤湿度,约为6.29%,全年最低土壤湿度出现在2月份,仅为4.16%左右;近10 a来,每年2月份土壤湿度的数据变化较大,C_(V)均超过15%,下游的土壤湿度数据变化较大,C_(V)均超过15%。研究成果为探明该区域生态气候、土壤湿度提供了依据。

Based on the MODIS satellite image data and field survey from 2010 to 2019,we accomplished the remotely-sensed monitoring of soil moisture in the main stream of Tarim River from a macroscopic perspective with the support of geographic information technology.Results revealed that the reflectance of MODIS band 7 was negatively correlated with soil moisture.Soil moisture in the upper,middle and lower reaches of the main stream of Tarim River varied greatly in space and time during the year.By comparing different river reaches in the same time period,we found that the soil moisture in the upper reaches of Tarim River was higher than that in the middle reaches and that in the lower reaches in sequence.Meanwhile,by comparing different time periods of the same reach,we discovered that the increment of soil moisture in the upper reaches was larger than that in the middle reaches and lower reaches in sequence.Moisture of soil(0-10 cm)in the main stream of Tarim River varied markedly among seasons.In 2019,the maximum soil moisture(6.29%)occurred in June,while the lowest(around 4.16%)in February.In the past decade,each February and lower reaches witnessed the biggest changes in soil moisture data,with the C_(V) both exceeding 15%.