| 引用本文: | 杨玉永,徐秀杰,杨丽萍.墒情遥感监测中热惯量模型的修正[J].灌溉排水学报,2018,37(6):54-59. |
| YANG Yuyong,XU Xiujie,YANG Liping.墒情遥感监测中热惯量模型的修正[J].灌溉排水学报,2018,37(6):54-59. |
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| 摘要: |
| 墒情是反映作物旱情态势的直观指标，但随作物发育植株叶片对土壤背景形成愈加强烈的郁闭作用，以热惯量法为基础的墒情反演模型精度随之降低。经试验对比分析可知，在作物发育早期即低植被覆盖区，增强植被指数（EVI）较归一化植被指数（NDVI）对植被的识别更为敏感，能够更好地削弱土壤背景影响。【目的】提高热惯量模型在墒情遥感监测中的精度和适用性。【方法】通过在常规热惯量模型中引入EVI作为影响因子，实现对常规热惯量模型的修正。【结果】修正后的热惯量模型在EVI均值不大于0.18时，平均反演精度可达80%以上。【结论】在相同自然条件下，修正热惯量模型反演精度和适用范围均优于常规热惯量模型。 |
| 关键词: 墒情； 热惯量； 植被指数； MODIS |
| 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 |
