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| DOI：10.13522/j.cnki.ggps.2017.0450 |
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| Modifying the Thermal Inertia Model in Use of Remote Sensing to Monitor Soil Moisture |
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YANG Yuyong， XU Xiujie， YANG Liping
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Shandong Earthquake Agency, Jinan 250014, China; Shandong Institute of Agricultural Sustainable Development, Jinan 250100, China
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| Abstract: |
| 【Objective】Remoting sensing has been increasingly used to monitor spatiotemporal variation of soil moisture but its accuracy and reliability deteriorate as crops grow due to the increased coverage of soil by canopy. The purpose of this paper is to investigate how to improve its accuracy by modifying the thermal inertia model. 【Method】 The method was based on the evidences that the enhanced vegetation index (EVI) is more sensitive to canopy in early crop growth stage than the normalized difference vegetation index (NDVI), and can be used to quantify the impact of soil coverage by canopy. We hence modified the thermal inertial model using the EVI to estimate soil moisture with remote sensing. 【Result】 It was found that, compared to the NDVI, the modified thermal inertia model could improve the accuracy of soil moisture estimate by 80% when the average EVI is less than 0.18. 【Conclusion】 The proposed model was proven to be an improved approach and can be used with remote sensing to monitor spatiotemporal soil moisture change in croplands. |
| Key words: soil moisture； thermal inertia； vegetation index； MODIS |
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