基于Sentinel-1与FY-3C数据反演植被覆盖地表土壤水分
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摘要
基于新一代的Sentinel-1SAR数据与FY-3C的MWRI数据,研究植被覆盖地表土壤湿度反演方法。为消除植被对土壤湿度反演影响,首先利用FY-3C/MWRI的微波极化差异指数MPDI,建立植被含水量反演模型;然后,结合植被含水量反演模型和水—云模型,发展一种主被动微波联合反演植被覆盖地表土壤含水量模型;最后,在江淮地区开展反演试验,利用观测的土壤湿度数据进行反演结果的精度验证。结果表明:(1)对于植被覆盖地表土壤湿度反演,由FY3C/MWRI提取的MPDI对于去除植被影响效果较好;(2)相比于VH极化哨兵1号卫星数据,VV极化数据更适用于土壤含水量的反演,能够得到更高的土壤湿度反演精度;(3)哨兵1号卫星数据能够获得较高精度的土壤含水量反演结果,试验反演的土壤湿度值与实测值相关系数为0.561 2,均方根误差为0.044cm~3/cm~3。
This study aims to develop soil moisture retrieval model over vegetated areas based on Sentinel-1 SAR and FY-3 Cdata.In order to remove vegetation effect,the MWRI data from FY-3 Cwas applied to establish the inversion model of vegetation water content.The model was combined with the original watercloud model,and developing a soil moisture retrieval model by combining active and passive microwave remote sensing data.Finally,the experiment of the soil moisture retrieval was conducted in Jiangsu and Anhui province,and validating the inversion accuracy of soil moisture by measured data.The results showed that:(1)For the vegetation-covered surface,the Microwave Polarization Difference Index obtain from FY-3 C/MWRI was suitable for removing vegetation effect.(2)Compared with the Sentinel-1 VH polarization data,the backscattering coefficient of VV polarization was more suitable for soil moisture retrieval and get a higher accuracy of soil moisture retrieval.(3)Sentinel-1 data can obtain high precision soil moisture estimation results,and the correlation coefficient between the estimated and measured soil moisture is 0.561 2 and RMSE is 0.044 cm~3/cm~3.
This study aims to develop soil moisture retrieval model over vegetated areas based on Sentinel-1 SAR and FY-3 Cdata.In order to remove vegetation effect,the MWRI data from FY-3 Cwas applied to establish the inversion model of vegetation water content.The model was combined with the original watercloud model,and developing a soil moisture retrieval model by combining active and passive microwave remote sensing data.Finally,the experiment of the soil moisture retrieval was conducted in Jiangsu and Anhui province,and validating the inversion accuracy of soil moisture by measured data.The results showed that:(1)For the vegetation-covered surface,the Microwave Polarization Difference Index obtain from FY-3 C/MWRI was suitable for removing vegetation effect.(2)Compared with the Sentinel-1 VH polarization data,the backscattering coefficient of VV polarization was more suitable for soil moisture retrieval and get a higher accuracy of soil moisture retrieval.(3)Sentinel-1 data can obtain high precision soil moisture estimation results,and the correlation coefficient between the estimated and measured soil moisture is 0.561 2 and RMSE is 0.044 cm~3/cm~3.
引文
[1]Hegarat-Mascle S L,Zribi M,Alem F,et al.Soil Moisture Estimation from ERS/SAR Data:Toward an Operational Methodology[J].IEEE Transactions on Geoscience and Remote Sensing,2002,40(12):2647-2658.
[2]Anagnostopoulos V,Petropoulos G P,Ireland G,et al.A Modernized Version of a 1DSoil Vegetation Atmosphere Transfer Model for Improving Its Future Use in Land Surface Interactions Studies[J].Environmental Modelling&Software,2017,90:147-156.
[3]Torres-Rua A,Ticlavilca A,Bachour R,et al.Estimation of Surface Soil Moisture in Irrigated Lands by Assimilation of Landsat Vegetation Indices,Surface Energy Balance Products,and Relevance Vector Machines[J].Water,2016,8(4):167.
[4]Bolten J D,Crow W T,Zhan X,et al.Evaluating the Utility of Remotely Sensed Soil Moisture Retrievals for Operational Agricultural Drought Monitoring[J].IEEE Journal of Selected Topics in Applied Earth Observations&Remote Sensing,2010,3(1):57-66.
[5]Pablos M,Martínezfernández J,Sánchez N,et al.Temporal and Spatial Comparison of Agricultural Drought Indices from Moderate Resolution Satellite Soil Moisture Data over Northwest Spain[J].Remote Sensing,2017,9(11):1168.
[6]Petropoulos G,Srivastava P,Piles M,et al.Earth Observation-based Operational Estimation of Soil Moisture and Evapotranspiration for Agricultural Crops in Support of Sustainable Water Management[J].Sustainability,2018,10(1):181.
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[8]Mao K B,Tang H J,Zhang L X,et al.A Method for Retrieving Soil Moisture in Tibet Region by Utilizing Microwave Index from TRMM/TMI Data[J].International Journal of Remote Sensing,2008,29(10):2903-2923.
[9]Srivastava P K,Han D,Rico-Ramirez M A,et al.Data Fusion Techniques for Improving Soil Moisture Deficit Using SMOS Satellite and WRF-NOAH Land Surface Model[J].Water Resources Management.2013,27(15):5069-5087.
[10]Lu L,Luo G P,Wang J Y.Development of An ATI-NDVIMethod for Estimation of Soil Moisture from MODIS data[J].International Journal of Remote Sensing,2014,35(10):3797-3815.
[11]Urso G D,Minacapilli M.A Semi-empirical Approach for Surface Soil Water Content Estimation from Radar Data without A-priori Information on Surface Roughness[J].Journal of Hydrology,2006,321(1/4):297-310.
[12]Wan Z,Wang P,Li X.Using MODIS Land Surface Temperature and Normalized Difference Vegetation Index Products for Monitoring Drought in The Southern Great Plains,USA[J].International Journal of Remote Sensing,2004,25(1):61-72.
[13]Zhao S,Yang Y,Qiu G,et al.Inversion of Soil Moisture Using Bi-temporal ASAR Images[J].Transactions of the Chinese Society of Agricultural Engineering,2008,24(6):184-188.[赵少华,杨永辉,邱国玉,等.基于双时相ASAR影像的土壤湿度反演研究[J].农业工程学报,2008,24(6):184-188.]
[14]Bao Yansong,Mao Fei,Min Jinzhong,et al.Retrieval of Bare Soil Moisture from FY-3B/MWRI Data[J].Remote Sensing for Land and Resources,2014,26(4):131-137.[鲍艳松,毛飞,闵锦忠,等.基于FY-3B/MWRI数据的裸土区土壤湿度反演[J].国土资源遥感,2014(4):131-137.]
[15]Zhang D,Zhou G.Estimation of Soil Moisture from Optical and Thermal Remote Sensing:A Review[J].Sensors,2016,16(8):1308.
[16]Tian Guoliang.Methods for Monitoring Soil Moisture Using Remote Sensing Technique[J].Journal of Remote Sensing,1991,6(2):89-98.[田国良.土壤水分的遥感监测方法[J].遥感学报,1991,6(2):89-98.]
[17]Paloscia S,Pettinato S,Santi E,et al.Soil Moisture Mapping Using Sentinel-1Images:Algorithm and Preliminary Validation[J].Remote Sensing of Environment,2013,134(4):234-248.
[18]He Lian,Qin Qiming,Ren Huazhong,et al.Soil Moisture Retrieval Using Multi-temporal Sentinel-1SAR Data in Agricultural Areas[J].Transactions of the Chinese Society of Agricultural Engineering,2016,32(3):142-148.[何连,秦其明,任华忠,等.利用多时相Sentinel-1SAR数据反演农田地表土壤水分[J].农业工程学报,2016,32(3):142-148.]
[19]Wang Jiao,Ding Jianli,Chen Wenqian,et al.Microwave Modeling of Soil Moisture in Oasis Regional Scalebased on Sentinel-1Radar Images[J].Journal of Infrared and Millimeter Waves,2017,36(1):120-127.[王娇,丁建丽,陈文倩,等.基于Sentinel-1的绿洲区域尺度土壤水分微波建模[J].红外与毫米波学报,2017,36(1):120-127.]
[20]Zeng Xujing,Xing Yanqiu,Shan Wei,et al.Soil Water Content Retrieval based on Sentinel-1Aand Landsat 8Image forBei’an-Heihe Expressway[J].Chinese Journal of Eco-Agriculture,2017,25(1):118-126.[曾旭婧,邢艳秋,单炜,等.基于Sentinel-1A与Landsat 8数据的北黑高速沿线地表土壤水分遥感反演方法研究[J].中国生态农业学报,2017,25(1):118-126.]
[21]Chu Qingwei,Zhang Hongqun,Wu Yewei,et al.Application Research of Landsat-8[J].Remote Sensing Information,2013,28(4):110-114.[初庆伟,张洪群,吴业炜,等.Landsat-8卫星数据应用探讨[J].遥感信息,2013,28(4):110-114.]
[22]Meng Q,Xie Q,Wang C,et al.A Fusion Approach of the Improved Dubois Model and Best Canopy Water Retrieval Models to Retrieve Soil Moisture Through All Maize Growth Stages from Radarsat-2and Landsat-8 Data[J].Environmental Earth Sciences,2016,75(20):1377.
[23]Lee J S,Jurkevich L,Dewaele P,et al.Speckle Filtering of Synthetic Aperture Radar Images:A Review[J].Remote Sensing Reviews,1994,8(4):255-267.
[24]Du Weina,Xu Aigong,Song Yaoxin,et al.Absolute Radiometric Calibration of Level-1 Detected Ground Range Products of New SAR Sensors[J].Remote Sensing for Land and Resources,2016,28(4):30-34.[杜伟娜,徐爱功,宋耀鑫,等.新型SAR传感器一级地距产品绝对辐射定标方法[J].国土资源遥感,2016,28(4):30-34.]
[25]Ma Yuan.Study on Soil Moisture Inversion and Application with Microwave Remote Sensing in Xinjiang[D].Urumqi:Xinjiang University,2007.[马媛.新疆土壤湿度的微波反演及应用研究[D].乌鲁木齐:新疆大学,2007.]
[26]Zhao Jiepeng,Zhang Xianfeng,Bao Haiyi,et al.Monitoring Land Surface Soil Moisture:Co-inversion of Visible,Infrared and Passive Microwave Sensing Data[J].Journal of Infrared and Millimeter Waves,2012,31(2):137-142.[赵杰鹏,张显峰,包慧漪,等.基于可见光红外与被动微波遥感的土壤水分协同反演[J].红外与毫米波学报,2012,31(2):137-142.]
[27]Bao Yansong,Liu Li,Kong Lingyan,et al.Soil Moisture Estimation at Various Growth Stages of Winter Wheat based on ASAR Data.[J].Transactions of the Chinese Society of Agricultural Engineering,2010,26(9):224-232.[鲍艳松,刘利,孔令寅,等.基于ASAR的冬小麦不同生育期土壤湿度反演[J].农业工程学报,2010,26(9):224-232.]
[28]Attema E P W,Ulaby F T.Vegetation Modeled as a WaterCloud[J].Radio Science,1978,13(2):357-364.
[29]Kumar K,Suryanarayana Rao H P,Arora M K.Study of Water Cloud Model Vegetation Descriptors in Estimating Soil Moisture in Solani Catchment[J].Hydrological Processes,2015,29(9):2137-2148.
[30]Xie Kaixin,Zhang Tingting,Shao Yun,et al.Study on SoilMoisture Inversion of Plateau Pasture Using Radarsat-2Imagery[J].Remote Sensing Technology and Application,2016,31(1):134-142.[谢凯鑫,张婷婷,邵芸,等.基于Radarsat-2全极化数据的高原牧草覆盖地表土壤水分反演[J].遥感技术与应用,2016,31(1):134-142.]
[31]Pierdicca N,Pulvirenti L,Bignami C,et al.Monitoring Soil Moisture in An Agricultural Test Site Using SAR Data:Design and Test of a Pre-operational Procedure[J].IEEE Journal of Selected Topics in Applied Earth Observations&Remote Sensing,2013,6(3):1199-1210.
[32]Choudhury B J,Tucker C J.Monitoring Global Vegetation Using Nimbus-7 37 GHz Data:Some Empirical Relations[J].International Journal of Remote Sensing,1987,8(7):1085-1090.
[33]Zhang Zhongjun,Sun Guoqing,Zhu Qijiang.The Study of Vegetation Effect on Passive Microwave Soil Moisture Retrieval[J].Journal of Remote Sensing,2004,8(3):207-213.[张钟军,孙国清,朱启疆.植被层对被动微波遥感土壤水分反演影响的研究[J].遥感学报,2004,8(3):207-213.]
[34]Mao Kebiao,Tang Huajun,Zhou Qingbo,et al.A Study of the Relationship between AMSR-E/MPI and MODIS LAI/NDVI[J].Remote Sensing for Land&Resources,2007,19(1):27-31.[毛克彪,唐华俊,周清波,等.AMSR-E微波极化指数与MODIS植被指数关系研究[J].国土资源遥感,2007,19(1):27-31.]
[35]Paloscia S,Pampaloni P.Microwave Polarization Index for Monitoring Vegetation Growth[J].IEEE Transactions on Geoscience&Remote Sensing,1988,26(5):617-621.
[36]Owe M,De Jeu R,Walker J.A Methodology for Surface Soil Moisture and Vegetation Optical Depth Retrieval Using the Microwave Polarization Difference Index[J].IEEE Transactions on Geoscience&Remote Sensing,2001,39(8):1643-1654.
[37]Mattia F,Satalino G,Dente L,et al.Using a Priori Information to Improve Soil Moisture Retrieval from ENVISAT ASAR AP Data in Semiarid Regions[J].IEEE Transactions on Geoscience&Remote Sensing,2006,44(4):900-912.
[38]Wigneron J P,Loumagne C,Normand M.Estimation of Watershed Soil Moisture Index from ERS/SAR Data[J].Remote Sensing of Environment,2000,72(3):290-303.
[39]Zribi M,Dechambre M.A New Empirical Model to Retrieve Soil Moisture and Roughness from C-band Radar Data[J].Remote Sensing of Environment,2003,84(1):42-52.
[40]Bao Y,Lin L,Wu S,et al.Surface Soil Moisture Retrievals over Partially Vegetated Areas from the Synergy of Sentinel-1and Landsat 8Data Using a Modified Water-cloud Model[J].International Journal of Applied Earth Observation&Geoinformation,2018,72:76-85.
[2]Anagnostopoulos V,Petropoulos G P,Ireland G,et al.A Modernized Version of a 1DSoil Vegetation Atmosphere Transfer Model for Improving Its Future Use in Land Surface Interactions Studies[J].Environmental Modelling&Software,2017,90:147-156.
[3]Torres-Rua A,Ticlavilca A,Bachour R,et al.Estimation of Surface Soil Moisture in Irrigated Lands by Assimilation of Landsat Vegetation Indices,Surface Energy Balance Products,and Relevance Vector Machines[J].Water,2016,8(4):167.
[4]Bolten J D,Crow W T,Zhan X,et al.Evaluating the Utility of Remotely Sensed Soil Moisture Retrievals for Operational Agricultural Drought Monitoring[J].IEEE Journal of Selected Topics in Applied Earth Observations&Remote Sensing,2010,3(1):57-66.
[5]Pablos M,Martínezfernández J,Sánchez N,et al.Temporal and Spatial Comparison of Agricultural Drought Indices from Moderate Resolution Satellite Soil Moisture Data over Northwest Spain[J].Remote Sensing,2017,9(11):1168.
[6]Petropoulos G,Srivastava P,Piles M,et al.Earth Observation-based Operational Estimation of Soil Moisture and Evapotranspiration for Agricultural Crops in Support of Sustainable Water Management[J].Sustainability,2018,10(1):181.
[7]Leroux D J,Kerr Y H,Bitar A A,et al.Comparison between SMOS,VUA,ASCAT,and ECMWF Soil Moisture Products Over Four Watersheds in U.S[J].IEEE Transactions on Geoscience&Remote Sensing,2013,52(3):1562-1571.
[8]Mao K B,Tang H J,Zhang L X,et al.A Method for Retrieving Soil Moisture in Tibet Region by Utilizing Microwave Index from TRMM/TMI Data[J].International Journal of Remote Sensing,2008,29(10):2903-2923.
[9]Srivastava P K,Han D,Rico-Ramirez M A,et al.Data Fusion Techniques for Improving Soil Moisture Deficit Using SMOS Satellite and WRF-NOAH Land Surface Model[J].Water Resources Management.2013,27(15):5069-5087.
[10]Lu L,Luo G P,Wang J Y.Development of An ATI-NDVIMethod for Estimation of Soil Moisture from MODIS data[J].International Journal of Remote Sensing,2014,35(10):3797-3815.
[11]Urso G D,Minacapilli M.A Semi-empirical Approach for Surface Soil Water Content Estimation from Radar Data without A-priori Information on Surface Roughness[J].Journal of Hydrology,2006,321(1/4):297-310.
[12]Wan Z,Wang P,Li X.Using MODIS Land Surface Temperature and Normalized Difference Vegetation Index Products for Monitoring Drought in The Southern Great Plains,USA[J].International Journal of Remote Sensing,2004,25(1):61-72.
[13]Zhao S,Yang Y,Qiu G,et al.Inversion of Soil Moisture Using Bi-temporal ASAR Images[J].Transactions of the Chinese Society of Agricultural Engineering,2008,24(6):184-188.[赵少华,杨永辉,邱国玉,等.基于双时相ASAR影像的土壤湿度反演研究[J].农业工程学报,2008,24(6):184-188.]
[14]Bao Yansong,Mao Fei,Min Jinzhong,et al.Retrieval of Bare Soil Moisture from FY-3B/MWRI Data[J].Remote Sensing for Land and Resources,2014,26(4):131-137.[鲍艳松,毛飞,闵锦忠,等.基于FY-3B/MWRI数据的裸土区土壤湿度反演[J].国土资源遥感,2014(4):131-137.]
[15]Zhang D,Zhou G.Estimation of Soil Moisture from Optical and Thermal Remote Sensing:A Review[J].Sensors,2016,16(8):1308.
[16]Tian Guoliang.Methods for Monitoring Soil Moisture Using Remote Sensing Technique[J].Journal of Remote Sensing,1991,6(2):89-98.[田国良.土壤水分的遥感监测方法[J].遥感学报,1991,6(2):89-98.]
[17]Paloscia S,Pettinato S,Santi E,et al.Soil Moisture Mapping Using Sentinel-1Images:Algorithm and Preliminary Validation[J].Remote Sensing of Environment,2013,134(4):234-248.
[18]He Lian,Qin Qiming,Ren Huazhong,et al.Soil Moisture Retrieval Using Multi-temporal Sentinel-1SAR Data in Agricultural Areas[J].Transactions of the Chinese Society of Agricultural Engineering,2016,32(3):142-148.[何连,秦其明,任华忠,等.利用多时相Sentinel-1SAR数据反演农田地表土壤水分[J].农业工程学报,2016,32(3):142-148.]
[19]Wang Jiao,Ding Jianli,Chen Wenqian,et al.Microwave Modeling of Soil Moisture in Oasis Regional Scalebased on Sentinel-1Radar Images[J].Journal of Infrared and Millimeter Waves,2017,36(1):120-127.[王娇,丁建丽,陈文倩,等.基于Sentinel-1的绿洲区域尺度土壤水分微波建模[J].红外与毫米波学报,2017,36(1):120-127.]
[20]Zeng Xujing,Xing Yanqiu,Shan Wei,et al.Soil Water Content Retrieval based on Sentinel-1Aand Landsat 8Image forBei’an-Heihe Expressway[J].Chinese Journal of Eco-Agriculture,2017,25(1):118-126.[曾旭婧,邢艳秋,单炜,等.基于Sentinel-1A与Landsat 8数据的北黑高速沿线地表土壤水分遥感反演方法研究[J].中国生态农业学报,2017,25(1):118-126.]
[21]Chu Qingwei,Zhang Hongqun,Wu Yewei,et al.Application Research of Landsat-8[J].Remote Sensing Information,2013,28(4):110-114.[初庆伟,张洪群,吴业炜,等.Landsat-8卫星数据应用探讨[J].遥感信息,2013,28(4):110-114.]
[22]Meng Q,Xie Q,Wang C,et al.A Fusion Approach of the Improved Dubois Model and Best Canopy Water Retrieval Models to Retrieve Soil Moisture Through All Maize Growth Stages from Radarsat-2and Landsat-8 Data[J].Environmental Earth Sciences,2016,75(20):1377.
[23]Lee J S,Jurkevich L,Dewaele P,et al.Speckle Filtering of Synthetic Aperture Radar Images:A Review[J].Remote Sensing Reviews,1994,8(4):255-267.
[24]Du Weina,Xu Aigong,Song Yaoxin,et al.Absolute Radiometric Calibration of Level-1 Detected Ground Range Products of New SAR Sensors[J].Remote Sensing for Land and Resources,2016,28(4):30-34.[杜伟娜,徐爱功,宋耀鑫,等.新型SAR传感器一级地距产品绝对辐射定标方法[J].国土资源遥感,2016,28(4):30-34.]
[25]Ma Yuan.Study on Soil Moisture Inversion and Application with Microwave Remote Sensing in Xinjiang[D].Urumqi:Xinjiang University,2007.[马媛.新疆土壤湿度的微波反演及应用研究[D].乌鲁木齐:新疆大学,2007.]
[26]Zhao Jiepeng,Zhang Xianfeng,Bao Haiyi,et al.Monitoring Land Surface Soil Moisture:Co-inversion of Visible,Infrared and Passive Microwave Sensing Data[J].Journal of Infrared and Millimeter Waves,2012,31(2):137-142.[赵杰鹏,张显峰,包慧漪,等.基于可见光红外与被动微波遥感的土壤水分协同反演[J].红外与毫米波学报,2012,31(2):137-142.]
[27]Bao Yansong,Liu Li,Kong Lingyan,et al.Soil Moisture Estimation at Various Growth Stages of Winter Wheat based on ASAR Data.[J].Transactions of the Chinese Society of Agricultural Engineering,2010,26(9):224-232.[鲍艳松,刘利,孔令寅,等.基于ASAR的冬小麦不同生育期土壤湿度反演[J].农业工程学报,2010,26(9):224-232.]
[28]Attema E P W,Ulaby F T.Vegetation Modeled as a WaterCloud[J].Radio Science,1978,13(2):357-364.
[29]Kumar K,Suryanarayana Rao H P,Arora M K.Study of Water Cloud Model Vegetation Descriptors in Estimating Soil Moisture in Solani Catchment[J].Hydrological Processes,2015,29(9):2137-2148.
[30]Xie Kaixin,Zhang Tingting,Shao Yun,et al.Study on SoilMoisture Inversion of Plateau Pasture Using Radarsat-2Imagery[J].Remote Sensing Technology and Application,2016,31(1):134-142.[谢凯鑫,张婷婷,邵芸,等.基于Radarsat-2全极化数据的高原牧草覆盖地表土壤水分反演[J].遥感技术与应用,2016,31(1):134-142.]
[31]Pierdicca N,Pulvirenti L,Bignami C,et al.Monitoring Soil Moisture in An Agricultural Test Site Using SAR Data:Design and Test of a Pre-operational Procedure[J].IEEE Journal of Selected Topics in Applied Earth Observations&Remote Sensing,2013,6(3):1199-1210.
[32]Choudhury B J,Tucker C J.Monitoring Global Vegetation Using Nimbus-7 37 GHz Data:Some Empirical Relations[J].International Journal of Remote Sensing,1987,8(7):1085-1090.
[33]Zhang Zhongjun,Sun Guoqing,Zhu Qijiang.The Study of Vegetation Effect on Passive Microwave Soil Moisture Retrieval[J].Journal of Remote Sensing,2004,8(3):207-213.[张钟军,孙国清,朱启疆.植被层对被动微波遥感土壤水分反演影响的研究[J].遥感学报,2004,8(3):207-213.]
[34]Mao Kebiao,Tang Huajun,Zhou Qingbo,et al.A Study of the Relationship between AMSR-E/MPI and MODIS LAI/NDVI[J].Remote Sensing for Land&Resources,2007,19(1):27-31.[毛克彪,唐华俊,周清波,等.AMSR-E微波极化指数与MODIS植被指数关系研究[J].国土资源遥感,2007,19(1):27-31.]
[35]Paloscia S,Pampaloni P.Microwave Polarization Index for Monitoring Vegetation Growth[J].IEEE Transactions on Geoscience&Remote Sensing,1988,26(5):617-621.
[36]Owe M,De Jeu R,Walker J.A Methodology for Surface Soil Moisture and Vegetation Optical Depth Retrieval Using the Microwave Polarization Difference Index[J].IEEE Transactions on Geoscience&Remote Sensing,2001,39(8):1643-1654.
[37]Mattia F,Satalino G,Dente L,et al.Using a Priori Information to Improve Soil Moisture Retrieval from ENVISAT ASAR AP Data in Semiarid Regions[J].IEEE Transactions on Geoscience&Remote Sensing,2006,44(4):900-912.
[38]Wigneron J P,Loumagne C,Normand M.Estimation of Watershed Soil Moisture Index from ERS/SAR Data[J].Remote Sensing of Environment,2000,72(3):290-303.
[39]Zribi M,Dechambre M.A New Empirical Model to Retrieve Soil Moisture and Roughness from C-band Radar Data[J].Remote Sensing of Environment,2003,84(1):42-52.
[40]Bao Y,Lin L,Wu S,et al.Surface Soil Moisture Retrievals over Partially Vegetated Areas from the Synergy of Sentinel-1and Landsat 8Data Using a Modified Water-cloud Model[J].International Journal of Applied Earth Observation&Geoinformation,2018,72:76-85.