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| DOI：10.13522/j.cnki.ggps.20170036 |
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| Spatial Distribution of Soil Moisture Estimated Using Thermal Vegetation Drought Indices |
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MA Chunya，WANG Jinglei，CHEN Zhen，YIN Huanqing, CHEN Yong, HUANG Xiuqiao
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1. Key Laboratory of Water-saving Agriculture , Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China; 2. Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, China; 3. Key Laboratory of Crop Water Use and Regulation, Ministry of Agriculture, Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China; 4. Huojia Management Office of Henan People’s Victory Canal Irrigation Area Administration, Xinxiang 453003, China; 5. Water Conservancy Bureau of Lanling County, Linyi 277700, China
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| Abstract: |
| 【Objective】Understanding inherent spatial variability of soil moisture at various scales can improve water management and soil moisture sampling in irrigation regions. The objective of this paper is to present a new method to estimate this based on vegetation drought indices.【Method】 The study was carried out in the People’s Victory Canal Irrigation District, and the Landsat 8 remote sensing imagery was used to estimate the vegetation drought index based on canopy temperature. The relationship between TVDI and the soil moisture calculated from the imagery and the ground-truth data was used to estimate soil moisture distribution in the studied area. Soil moisture variation at two spatial scales was studied using the classical statistical and geo-statistical methods.【Result】The soil moisture in the two spatial scales followed normal distribution, and the variation coefficient of the soil moisture increased with scale and spatial resolution. The corresponding ratio of the spatial heterogeneity C0/(C0+C), where C0 was the nugget and C0+C was the sill of the small scale, was less than 0.25, indicating a strong spatial autocorrelation at small scale. The corresponding ratio of spatial heterogeneity at regional scale was between 0.25 and 0.75, indicating a moderate correlation at regional scale. The variation coefficient, the variation range and the corresponding ratio of spatial heterogeneity all showed limited change at different resolutions at regional scale.【Conclusion】Our results alluded that using point-measured data and interpolation method is inappropriate to estimate soil moisture in the People’s Victory Canal Irrigation District, and remote sensing method works better for estimating soil moisture distribution at regional scale. |
| Key words: Temperature Vegetation Drought Index; soil moisture; spatial variability |
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