基于△Ts-Albedo光谱信息的土壤水分监测新指数研究

摘要

Monitoring soil moisture by remote sensing has been an important problem for both agricultural drought monitoring and water resources management. In the present paper, we acquire the land surface temperature difference (ΔTs)and broadband albedo using MODIS Terra reflectance and land surface temperature products to construct the ΔTs-albedo spectral feature space.According to the soil moisture variation in spectral feature space, we put forward a simple and practical temperature difference albedo drought index (TDADI) and validate it using ground-measured 0 ～ 10 cm averaged soil moisture of Ningxia plain. The results show that the coefficient of determination (R2) of both them varies from 0. 36 to 0. 52, and TDADI has higher accuracy than temperature albedo drought index (TADI) for soil moisture retrieval. The good agreement of TDADI, Albedo/LST, LST/NDVI and TVDI for analyzing the trends of soil moisture change supports the reliability of TDADI. However, TDADI has been designed only at Ningxia plain and still needs further validation in other regions.%土壤水分的遥感监测在农业干旱和水资源管理方面具有重要的意义.利用MODIS反射率和温度产品来获取地表昼夜温差(△Ts)和宽波段反照率(Albedo),构建△Ts-Albedo光谱特征空间,提出温差-反照率干旱指数(temperature difference albedo drought index,TDADI)用来监测土壤水分,并利用宁夏实测0～10cm平均土壤含水量数据验证该指数的精度,结果表明:它们之间的相关性较好,R2变化范围为0.36～0.52.TDADI与TAD/相比,该指数具有更高的土壤水分监测精度.然而,由于数据获取的局限性,只采用了宁夏平原数据对TDADI进行验证,在其他区域仍需要进一步验证.