Soil moisture retrieval from remote sensing measurements: Current knowledge and directions for the future

Abstract Soil moisture (SM) is an essential parameter for understanding the interactions and feedbacks between the atmosphere and the Earth's surface through energy and water cycles. Knowledge of the spatiotemporal distribution of land surface SM has long been a challenge in the remote sensing community. Over the past 50 years, electromagnetic spectra, from the optical/thermal to the microwave regions, have been intensively investigated for SM retrieval, providing a number of algorithms, models and products that are available for actual applications nowadays. However, certain issues with respect to retrieval accuracy, spatiotemporal resolution, and data consistency exist and remain unsolved between the state-of-the-art of SM retrieval and readily-used SM datasets for various domains at field, regional/watershed or global scales. In particular, several new theories and algorithms for SM retrieval proposed in recent years have not been well documented in previous articles. Therefore, a critical review of the established and emerging SM retrieval methods with respect to their advantages and disadvantages is necessary. In present study, future directions for each method are highlighted to address the scientific challenges of SM retrieval in the new era of rapid data expansion.

[1]  Dara Entekhabi,et al.  Improved SMAP Dual-Channel Algorithm for the Retrieval of Soil Moisture , 2020, IEEE Transactions on Geoscience and Remote Sensing.

[2]  Mehrez Zribi,et al.  Semiempirical Calibration of the Integral Equation Model for SAR Data in C-Band and Cross Polarization Using Radar Images and Field Measurements , 2011, IEEE Geoscience and Remote Sensing Letters.

[3]  Mahta Moghaddam,et al.  A Combined Active–Passive Soil Moisture Estimation Algorithm With Adaptive Regularization in Support of SMAP , 2015, IEEE Transactions on Geoscience and Remote Sensing.

[4]  Jeffrey P. Walker,et al.  Upscaling sparse ground‐based soil moisture observations for the validation of coarse‐resolution satellite soil moisture products , 2012 .

[5]  Seokhyeon Kim,et al.  Using 3D robust smoothing to fill land surface temperature gaps at the continental scale , 2019, Int. J. Appl. Earth Obs. Geoinformation.

[6]  J. R. Eagleman,et al.  Remote sensing of soil moisture by a 21-cm passive radiometer. [onboard Skylab] , 1976 .

[7]  W. Mauser,et al.  Modelling and model verification of the spectral reflectance of soils under varying moisture conditions , 1994, Proceedings of IGARSS '94 - 1994 IEEE International Geoscience and Remote Sensing Symposium.

[8]  S. Paloscia,et al.  An algorithm for generating soil moisture and snow depth maps from microwave spaceborne radiometers: HydroAlgo , 2012 .

[9]  Buford Randall Jean,et al.  Soil Moisture Information And Thermal Microwave Emission , 1982, IEEE Transactions on Geoscience and Remote Sensing.

[10]  Mehrez Zribi,et al.  Soil Texture Estimation Using Radar and Optical Data from Sentinel-1 and Sentinel-2 , 2019, Remote. Sens..

[11]  G. P. Petropoulos,et al.  Evaluating the capabilities of optical/TIR imaging sensing systems for quantifying soil water content , 2018, Geocarto International.

[12]  S. Ustin,et al.  Predicting water content using Gaussian model on soil spectra , 2004 .

[13]  David M. Le Vine,et al.  Aquarius Active/Passive RFI Environment at L-Band , 2014, IEEE Geoscience and Remote Sensing Letters.

[14]  Pascale C. Dubois,et al.  Measuring soil moisture with imaging radars , 1995, IEEE Trans. Geosci. Remote. Sens..

[15]  Thomas J. Jackson,et al.  High-resolution change estimation of soil moisture using L-band radiometer and Radar observations made during the SMEX02 experiments , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[16]  Wade T. Crow,et al.  A Review of the Applications of ASCAT Soil Moisture Products , 2017, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.

[17]  Hao Sun,et al.  Two-Stage Trapezoid: A New Interpretation of the Land Surface Temperature and Fractional Vegetation Coverage Space , 2016, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.

[18]  A. Ångström The Albedo of Various Surfaces of Ground , 1925 .

[19]  A. Al Bitar,et al.  Evaluating soil moisture retrievals from ESA's SMOS and NASA's SMAP brightness temperature datasets. , 2017, Remote sensing of environment.

[20]  Michael T. Green,et al.  Iron(IV)hydroxide pKa and the Role of Thiolate Ligation in C–H Bond Activation by Cytochrome P450 , 2013, Science.

[21]  Jean-Pierre Wigneron,et al.  On the measurement of microwave vegetation properties: some guidelines for a protocol , 2004, IEEE Transactions on Geoscience and Remote Sensing.

[22]  F. Aires,et al.  Soil moisture retrieval from AMSR-E and ASCAT microwave observation synergy. Part 1: Satellite data analysis , 2016 .

[23]  Thomas J. Jackson,et al.  The SMAP mission combined active-passive soil moisture product at 9 km and 3 km spatial resolutions , 2018, Remote Sensing of Environment.

[24]  M. Baghini,et al.  A critical review of soil moisture measurement , 2014 .

[25]  Malcolm Davidson,et al.  Dense Temporal Series of C- and L-band SAR Data for Soil Moisture Retrieval Over Agricultural Crops , 2011, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.

[26]  Thomas Schmugge,et al.  Passive Microwave Soil Moisture Research , 1986, IEEE Transactions on Geoscience and Remote Sensing.

[27]  Marco Brogioni,et al.  Radar Bistatic Configurations for Soil Moisture Retrieval: A Simulation Study , 2008, IEEE Transactions on Geoscience and Remote Sensing.

[28]  P. Beckmann,et al.  The scattering of electromagnetic waves from rough surfaces , 1963 .

[29]  Fawwaz T. Ulaby,et al.  Effects of Vegetation Cover on the Radar Sensitivity to Soil Moisture , 1982, IEEE Transactions on Geoscience and Remote Sensing.

[30]  Nengcheng Chen,et al.  Satellite surface soil moisture from SMAP, SMOS, AMSR2 and ESA CCI: A comprehensive assessment using global ground-based observations , 2019, Remote Sensing of Environment.

[31]  Zhiming Zhan,et al.  Designing of the perpendicular drought index , 2007 .

[32]  Zhao-Liang Li,et al.  An Effective Emission Depth Model for Passive Microwave Remote Sensing , 2016, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.

[33]  Kamal Sarabandi,et al.  Michigan microwave canopy scattering model , 1990 .

[34]  J. Qin,et al.  High spatio-temporal resolution mapping of soil moisture by integrating wireless sensor network observations and MODIS apparent thermal inertia in the Babao River Basin, China , 2017 .

[35]  J. Qu,et al.  Satellite remote sensing applications for surface soil moisture monitoring: A review , 2009 .

[36]  W. Crow,et al.  L band microwave remote sensing and land data assimilation improve the representation of prestorm soil moisture conditions for hydrologic forecasting , 2017, Geophysical research letters.

[37]  Jin Chen,et al.  Global land cover mapping at 30 m resolution: A POK-based operational approach , 2015 .

[38]  Olivier Merlin,et al.  Retrieving surface soil moisture at high spatio-temporal resolution from a synergy between Sentinel-1 radar and Landsat thermal data: A study case over bare soil , 2018, Remote Sensing of Environment.

[39]  Zhao-Liang Li,et al.  A practical algorithm for estimating surface soil moisture using combined optical and thermal infrared data , 2016, Int. J. Appl. Earth Obs. Geoinformation.

[40]  D. Lawrence,et al.  Regions of Strong Coupling Between Soil Moisture and Precipitation , 2004, Science.

[41]  B. Choudhury,et al.  Remote sensing of soil moisture content over bare field at 1.4 GHz frequency , 1981 .

[42]  Filipe Aires,et al.  Temporal interpolation of global surface skin temperature diurnal cycle over land under clear and cloudy conditions , 2004 .

[43]  Paolo Ferrazzoli,et al.  Combined use of active and passive microwave satellite data to constrain a discrete scattering model , 2014 .

[44]  Mehrez Zribi,et al.  X-band Terrasar-X and COSMO-SkyMed SAR data for bare soil parameters estimation , 2014, 2014 IEEE Geoscience and Remote Sensing Symposium.

[45]  Compton J. Tucker,et al.  Monitoring vegetation using Nimbus-7 scanning multichannel microwave radiometer's data , 1987 .

[46]  Wade T. Crow,et al.  A method for retrieving high-resolution surface soil moisture from hydros L-band radiometer and Radar observations , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[47]  Lun Gao,et al.  Microwave retrievals of soil moisture and vegetation optical depth with improved resolution using a combined constrained inversion algorithm: Application for SMAP satellite , 2020 .

[48]  Leung Tsang,et al.  Electromagnetic Computation in Scattering of Electromagnetic Waves by Random Rough Surface and Dense Media in Microwave Remote Sensing of Land Surfaces , 2013, Proceedings of the IEEE.

[49]  Johan Alexander Huisman,et al.  Emerging methods for noninvasive sensing of soil moisture dynamics from field to catchment scale: a review , 2015 .

[50]  W. Wagner,et al.  Evaluation of the ESA CCI soil moisture product using ground-based observations , 2015 .

[51]  Jean-Pierre Wigneron,et al.  Sensitivity of Passive Microwave Observations to Soil Moisture and Vegetation Water Content: L-Band to W-Band , 2011, IEEE Transactions on Geoscience and Remote Sensing.

[52]  Arnaud Mialon,et al.  SMOS-IC: An Alternative SMOS Soil Moisture and Vegetation Optical Depth Product , 2017, Remote. Sens..

[53]  Jindi Wang,et al.  Spatially and Temporally Complete Satellite Soil Moisture Data Based on a Data Assimilation Method , 2016, Remote. Sens..

[54]  Dara Entekhabi,et al.  An Algorithm for Merging SMAP Radiometer and Radar Data for High-Resolution Soil-Moisture Retrieval , 2011, IEEE Transactions on Geoscience and Remote Sensing.

[55]  Thomas J. Schmugge,et al.  An interpretation of methodologies for indirect measurement of soil water content , 1995 .

[56]  R. Jeu,et al.  Multisensor historical climatology of satellite‐derived global land surface moisture , 2008 .

[57]  Philippe Richaume,et al.  Soil Moisture Retrieval Using Neural Networks: Application to SMOS , 2015, IEEE Transactions on Geoscience and Remote Sensing.

[58]  W. Verstraeten,et al.  Soil moisture content retrieval based on apparent thermal inertia for Xinjiang province in China , 2012 .

[59]  Paulin Coulibaly,et al.  Advances in soil moisture retrieval from synthetic aperture radar and hydrological applications , 2013 .

[60]  Saeid Parsian,et al.  Two new soil moisture indices based on the NIR-red triangle space of Landsat-8 data , 2016, Int. J. Appl. Earth Obs. Geoinformation.

[61]  George P. Petropoulos,et al.  Surface soil moisture retrievals over partially vegetated areas from the synergy of Sentinel-1 and Landsat 8 data using a modified water-cloud model , 2018, Int. J. Appl. Earth Obs. Geoinformation.

[62]  Filipe Aires,et al.  Soil moisture retrieval from AMSR-E and ASCAT microwave observation synergy. Part 2: Product evaluation , 2017 .

[63]  C. Loumagne,et al.  Analysis of TerraSAR-X data and their sensitivity to soil surface parameters over bare agricultural fields , 2008 .

[64]  D. Lobell,et al.  Moisture effects on soil reflectance , 2002 .

[65]  Simonetta Paloscia,et al.  Remote monitoring of soil moisture using passive microwave-based techniques — Theoretical basis and overview of selected algorithms for AMSR-E , 2014 .

[66]  Thomas J. Jackson,et al.  Global Soil Moisture From the Aquarius/SAC-D Satellite: Description and Initial Assessment , 2015, IEEE Geoscience and Remote Sensing Letters.

[67]  J. C. Price Thermal inertia mapping: A new view of the Earth , 1977 .

[68]  Emanuele Santi,et al.  pplication of artificial neural networks for the soil moisture retrieval rom active and passive microwave spaceborne sensors , 2015 .

[69]  José A. Sobrino,et al.  Combining afternoon and morning NOAA satellites for thermal inertia estimation. 1. Algorithm and its testing with Hydrologic Atmospheric Pilot Experiment-Sahel data , 1999 .

[70]  Guoqing Zhou,et al.  Estimation of Soil Moisture from Optical and Thermal Remote Sensing: A Review , 2016, Sensors.

[71]  P. Richaume,et al.  Assessment and inter-comparison of recently developed/reprocessed microwave satellite soil moisture products using ISMN ground-based measurements , 2019, Remote Sensing of Environment.

[72]  Yuyu Zhou,et al.  Creating a seamless 1 km resolution daily land surface temperature dataset for urban and surrounding areas in the conterminous United States , 2018 .

[73]  Tingting Zhang,et al.  Modeling and Mapping Soil Moisture of Plateau Pasture Using RADARSAT-2 Imagery , 2015, Remote. Sens..

[74]  A. Verhoef Remote estimation of thermal inertia and soil heat flux for bare soil , 2004 .

[75]  Arnaud Mialon,et al.  The SMOS Soil Moisture Retrieval Algorithm , 2012, IEEE Transactions on Geoscience and Remote Sensing.

[76]  Thomas Jagdhuber,et al.  Physics-Based Modeling of Active and Passive Microwave Covariations Over Vegetated Surfaces , 2019, IEEE Transactions on Geoscience and Remote Sensing.

[77]  Zhao-Liang Li,et al.  Preliminary validation of two temporal parameter-based soil moisture retrieval models using a satellite product and in situ soil moisture measurements over the REMEDHUS network , 2016 .

[78]  Alicia T. Joseph,et al.  Soil Moisture Retrieval During a Corn Growth Cycle Using L-Band (1.6 GHz) Radar Observations , 2007, IEEE Transactions on Geoscience and Remote Sensing.

[79]  Hua Yuan,et al.  A global soil data set for earth system modeling , 2014 .

[80]  M. Shahriari,et al.  Predicting regional spatial distribution of soil texture in floodplains using remote sensing data: A case of southeastern Iran , 2019, CATENA.

[81]  Xiaotao Li,et al.  Estimating Vegetation Water Content of Corn and Soybean Using Different Polarization Ratios Based on L- and S-Band Radar Data , 2017, IEEE Geoscience and Remote Sensing Letters.

[82]  S. Jones,et al.  Ground, Proximal, and Satellite Remote Sensing of Soil Moisture , 2019, Reviews of Geophysics.

[83]  Arnaud Mialon,et al.  Considering combined or separated roughness and vegetation effects in soil moisture retrievals , 2017, Int. J. Appl. Earth Obs. Geoinformation.

[84]  Philippe Richaume,et al.  SMOS retrieval over forests: Exploitation of optical depth and tests of soil moisture estimates , 2016 .

[85]  Zhanqing Li,et al.  Estimation of evaporative fraction from a combination of day and night land surface temperatures and NDVI: A new method to determine the Priestley-Taylor parameter , 2006 .

[86]  Tianjie Zhao,et al.  Detection and mitigation of radiometers radio-frequency interference by using the local outlier factor , 2017 .

[87]  Hong Zhao,et al.  Estimation of Penetration Depth from Soil Effective Temperature in Microwave Radiometry , 2018, Remote. Sens..

[88]  E. Muller,et al.  Modeling soil moisture-reflectance , 2001 .

[89]  José Martínez-Fernández,et al.  Satellite soil moisture for agricultural drought monitoring: Assessment of the SMOS derived Soil Water Deficit Index , 2016 .

[90]  Mehrez Zribi,et al.  Relationship between soil moisture and vegetation in the Kairouan plain region of Tunisia using low spatial resolution satellite data , 2010 .

[91]  Richard de Jeu,et al.  Analytical derivation of the vegetation optical depth from the microwave polarization difference index , 2005, IEEE Geoscience and Remote Sensing Letters.

[92]  Y. Kerr,et al.  L-band Microwave Emission of the Biosphere (L-MEB) Model: Description and calibration against experimental data sets over crop fields , 2007 .

[93]  Guofei Shang,et al.  Evapotranspiration Retrieval Under Different Aridity Conditions Over North American Grasslands , 2020, IEEE Transactions on Geoscience and Remote Sensing.

[94]  Y. Kerr,et al.  Semi-empirical regressions at L-band applied to surface soil moisture retrievals over grass , 2006 .

[95]  F. Ulaby,et al.  Vegetation modeled as a water cloud , 1978 .

[96]  T. Jackson,et al.  Soil moisture estimates from TRMM Microwave Imager observations over the Southern United States , 2003 .

[97]  Luca Brocca,et al.  A physically based approach for the estimation of root-zone soil moisture from surface measurements , 2012 .

[98]  Dara Entekhabi,et al.  Vegetation optical depth and scattering albedo retrieval using time series of dual-polarized L-band radiometer observations , 2016 .

[99]  Yi Y. Liu,et al.  ESA CCI Soil Moisture for improved Earth system understanding : State-of-the art and future directions , 2017 .

[100]  L. Simmonds,et al.  A simple parameterisation for retrieving soil moisture from passive microwave data , 2001 .

[101]  Wade T. Crow,et al.  An ensemble Kalman filter dual assimilation of thermal infrared and microwave satellite observations of soil moisture into the Noah land surface model , 2012 .

[102]  Yong Xue,et al.  Advanced thermal inertia modelling , 1995 .

[103]  George P. Petropoulos,et al.  Towards improved spatio-temporal resolution soil moisture retrievals from the synergy of SMOS and MSG SEVIRI spaceborne observations , 2016 .

[104]  Arnaud Mialon,et al.  Global-scale surface roughness effects at L-band as estimated from SMOS observations. , 2016 .

[105]  A. Sahoo,et al.  Improving soil moisture retrievals from a physically-based radiative transfer model , 2014 .

[106]  Sosdito Mananze,et al.  Agricultural drought monitoring based on soil moisture derived from the optical trapezoid model in Mozambique , 2019, Journal of Applied Remote Sensing.

[107]  Klaus Scipal,et al.  An Improved Soil Moisture Retrieval Algorithm for ERS and METOP Scatterometer Observations , 2009, IEEE Transactions on Geoscience and Remote Sensing.

[108]  Claudia Notarnicola,et al.  Use of radar and optical remotely sensed data for soil moisture retrieval over vegetated areas , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[109]  Emmanouil N. Anagnostou,et al.  A combined passive/active microwave remote sensing approach for surface variable retrieval using Tropical Rainfall Measuring Mission observations , 2004 .

[110]  Scott B. Jones,et al.  Mapping soil moisture with the OPtical TRApezoid Model (OPTRAM) based on long-term MODIS observations , 2018, Remote Sensing of Environment.

[111]  Q. Qin,et al.  Modified perpendicular drought index (MPDI): a real-time drought monitoring method , 2007 .

[112]  Piero Toscano,et al.  Retrieving soil moisture in rainfed and irrigated fields using Sentinel-2 observations and a modified OPTRAM approach , 2020, Int. J. Appl. Earth Obs. Geoinformation.

[113]  F. Ulaby,et al.  Microwave Dielectric Behavior of Wet Soil-Part 1: Empirical Models and Experimental Observations , 1985, IEEE Transactions on Geoscience and Remote Sensing.

[114]  Urs Wegmüller,et al.  Rough bare soil reflectivity model , 1999, IEEE Trans. Geosci. Remote. Sens..

[115]  T. Schmugge Remote Sensing of Soil Moisture: Recent Advances , 1983, IEEE Transactions on Geoscience and Remote Sensing.

[116]  Albert Olioso,et al.  Retrieval of evapotranspiration over the Alpilles/ReSeDA experimental site using airborne POLDER sensor and a thermal camera , 2005 .

[117]  Martha C. Anderson,et al.  Vegetation water content mapping using Landsat data derived normalized difference water index for corn and soybeans , 2004 .

[118]  George P. Petropoulos,et al.  Surface soil moisture retrievals from remote sensing: Current status, products & future trends , 2015 .

[119]  Jeffrey P. Walker,et al.  A roadmap for high-resolution satellite soil moisture applications , 2021, Remote Sensing of Environment.

[120]  I. Sandholt,et al.  A simple interpretation of the surface temperature/vegetation index space for assessment of surface moisture status , 2002 .

[121]  Yi Y. Liu,et al.  Trend-preserving blending of passive and active microwave soil moisture retrievals , 2012 .

[122]  Adriano Camps,et al.  A Change Detection Algorithm for Retrieving High-Resolution Soil Moisture From SMAP Radar and Radiometer Observations , 2009, IEEE Transactions on Geoscience and Remote Sensing.

[123]  Thomas Jagdhuber,et al.  The SMAP and Copernicus Sentinel 1A/B microwave active-passive high resolution surface soil moisture product , 2019, Remote Sensing of Environment.

[124]  Soon-Koo Kweon,et al.  A Modified Water-Cloud Model With Leaf Angle Parameters for Microwave Backscattering From Agricultural Fields , 2015, IEEE Transactions on Geoscience and Remote Sensing.

[125]  Francesco Mattia,et al.  A Time-Series Approach to Estimating Soil Moisture From Vegetated Surfaces Using L-Band Radar Backscatter , 2017, IEEE Transactions on Geoscience and Remote Sensing.

[126]  T. Carlson,et al.  Satellite Estimation of the Surface Energy Balance, Moisture Availability and Thermal Inertia. , 1981 .

[127]  M. S. Moran,et al.  Estimating crop water deficit using the relation between surface-air temperature and spectral vegetation index , 1994 .

[128]  Wenjiang Huang,et al.  A method of estimating soil moisture based on the linear decomposition of mixture pixels , 2013, Math. Comput. Model..

[129]  E. Njoku,et al.  Passive microwave remote sensing of soil moisture , 1996 .

[130]  C. Montzka,et al.  Soil moisture retrieval from airborne L-band passive microwave using high resolution multispectral data , 2014 .

[131]  Zhihao Qin,et al.  An Efficient Approach to Remove Thick Cloud in VNIR Bands of Multi-Temporal Remote Sensing Images , 2019, Remote. Sens..

[132]  Yisok Oh,et al.  Quantitative retrieval of soil moisture content and surface roughness from multipolarized radar observations of bare soil surfaces , 2004, IEEE Transactions on Geoscience and Remote Sensing.

[133]  Douglas A. Stow,et al.  The Relationship Between Soil Moisture and NDVI Near Barrow, Alaska , 2008 .

[134]  Luca Brocca,et al.  Toward Global Soil Moisture Monitoring With Sentinel-1: Harnessing Assets and Overcoming Obstacles , 2019, IEEE Transactions on Geoscience and Remote Sensing.

[135]  Samuel N. Goward,et al.  Evaluating land surface moisture conditions from the remotely sensed temperature/vegetation index measurements: An exploration with the simplified simple biosphere model , 2002 .

[136]  Emanuele Santi,et al.  Soil moisture mapping using Sentinel-1 images: Algorithm and preliminary validation , 2013 .

[137]  T. Jackson,et al.  Using TRMM/TMI to Retrieve Surface Soil Moisture over the Southern United States from 1998 to 2002 , 2006 .

[138]  Yann Kerr,et al.  Soil moisture retrievals from biangular L-band passive microwave observations , 2004, IEEE Geoscience and Remote Sensing Letters.

[139]  Zhao-Liang Li,et al.  A framework for the retrieval of all-weather land surface temperature at a high spatial resolution from polar-orbiting thermal infrared and passive microwave data , 2017 .

[140]  Adrian K. Fung,et al.  Backscattering from a randomly rough dielectric surface , 1992, IEEE Trans. Geosci. Remote. Sens..

[141]  Wolfgang Wagner,et al.  A Generic First-Order Radiative Transfer Modelling Approach for the Inversion of Soil and Vegetation Parameters from Scatterometer Observations , 2019, Remote. Sens..

[142]  Yi Y. Liu,et al.  Global surface soil moisture from the Microwave Radiation Imager onboard the Fengyun-3B satellite , 2014 .

[143]  Yi Y. Liu,et al.  Developing an improved soil moisture dataset by blending passive and active microwave satellite-based retrievals , 2011 .

[144]  Zhongbo Su,et al.  Determination of land surface temperature and soil moisture from Tropical Rainfall Measuring Mission/Microwave Imager remote sensing data , 2003 .

[145]  Arnaud Mialon,et al.  Comparison of SMOS and AMSR-E vegetation optical depth to four MODIS-based vegetation indices , 2016 .

[146]  Markus Metz,et al.  A New Fully Gap-Free Time Series of Land Surface Temperature from MODIS LST Data , 2017, Remote. Sens..

[147]  H. Lei,et al.  Generation of spatially complete and daily continuous surface soil moisture of high spatial resolution , 2019, Remote Sensing of Environment.

[148]  Niko E. C. Verhoest,et al.  Assessment of the operational applicability of RADARSAT-1 data for surface soil moisture estimation , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[149]  R. Horton,et al.  Accounting for soil porosity improves a thermal inertia model for estimating surface soil water content , 2018 .

[150]  Hui Lin,et al.  Monitoring Sugarcane Growth Using ENVISAT ASAR Data , 2009, IEEE Transactions on Geoscience and Remote Sensing.

[151]  J. C. Price On the analysis of thermal infrared imagery: The limited utility of apparent thermal inertia , 1985 .

[152]  Li Li,et al.  Retrieval of land surface parameters using passive microwave measurements at 6-18 GHz , 1999, IEEE Trans. Geosci. Remote. Sens..

[153]  Thomas J. Jackson,et al.  Monitoring soybean growth using L-, C-, and X-band scatterometer data , 2013 .

[154]  Wade T. Crow,et al.  Monitoring root-zone soil moisture through the assimilation of a thermal remote sensing-based soil moisture proxy into a water balance model , 2008 .

[155]  J. Qu,et al.  NMDI: A normalized multi‐band drought index for monitoring soil and vegetation moisture with satellite remote sensing , 2007 .

[156]  Chao-Hung Lin,et al.  Cloud Removal From Multitemporal Satellite Images Using Information Cloning , 2013, IEEE Transactions on Geoscience and Remote Sensing.

[157]  Philip Marzahn,et al.  Global assessments of two blended microwave soil moisture products CCI and SMOPS with in-situ measurements and reanalysis data , 2021, Int. J. Appl. Earth Obs. Geoinformation.

[158]  Alireza Tabatabaeenejad,et al.  Retrieving Root-Zone Soil Moisture Profile From P-Band Radar via Hybrid Global and Local Optimization , 2020, IEEE Transactions on Geoscience and Remote Sensing.

[159]  Albert Olioso,et al.  Application of a simple algorithm to estimate daily evapotranspiration from NOAA–AVHRR images for the Iberian Peninsula , 2007 .

[160]  Jeffrey P. Walker,et al.  Fusing Microwave and Optical Satellite Observations to Simultaneously Retrieve Surface Soil Moisture, Vegetation Water Content, and Surface Soil Roughness , 2017, IEEE Transactions on Geoscience and Remote Sensing.

[161]  J. Wigneron,et al.  Retrieving near-surface soil moisture from microwave radiometric observations: current status and future plans , 2003 .

[162]  T. Schmugge,et al.  Remote sensing of soil moisture with microwave radiometers , 1974 .

[163]  Bo-Hui Tang,et al.  A Simple Method for Soil Moisture Determination From LST–VI Feature Space Using Nonlinear Interpolation Based on Thermal Infrared Remotely Sensed Data , 2015, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.

[164]  Toby N. Carlson,et al.  On estimating total daily evapotranspiration from remote surface temperature measurements , 1989 .

[165]  Luca Brocca,et al.  Soil Moisture from Fusion of Scatterometer and SAR: Closing the Scale Gap with Temporal Filtering , 2018, Remote. Sens..

[166]  L. Guerriero,et al.  Synergy of active and passive signatures to decouple soil and vegetation effects , 2010, 2010 11th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment.

[167]  David M. Le Vine,et al.  Dependence of attenuation in a vegetation canopy on frequency and plant water content , 1996, IEEE Trans. Geosci. Remote. Sens..

[168]  D. Entekhabi,et al.  Simultaneous Retrieval of Surface Roughness Parameters for Bare Soils From Combined Active–Passive Microwave SMAP Observations , 2021, IEEE Transactions on Geoscience and Remote Sensing.

[169]  Si-Bo Duan,et al.  Determination of all-sky surface soil moisture at fine spatial resolution synergistically using optical/thermal infrared and microwave measurements , 2019 .

[170]  Robert M. Parinussa,et al.  Soil Moisture Retrievals From the WindSat Spaceborne Polarimetric Microwave Radiometer , 2012, IEEE Transactions on Geoscience and Remote Sensing.

[171]  M. S. Moran,et al.  Estimating soil moisture at the watershed scale with satellite-based radar and land surface models , 2004 .

[172]  M. Raffy,et al.  An inverse problem occurring in remote sensing in the thermal infrared bands and its solutions , 1985 .

[173]  L. Guerriero,et al.  A synergyc view of L-band active and passive remote sensing of vegetated soil , 2012, 2012 12th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment (MicroRad).

[174]  Mehrez Zribi,et al.  Synergic Use of Sentinel-1 and Sentinel-2 Images for Operational Soil Moisture Mapping at High Spatial Resolution over Agricultural Areas , 2017, Remote. Sens..

[175]  Reiji Kimura,et al.  Soil Moisture Estimation Using Thermal Inertia: Potential and Sensitivity to Data Conditions , 2012 .

[176]  Zhao-Liang Li,et al.  Atmospheric correction for retrieving ground brightness temperature at commonly-used passive microwave frequencies. , 2017, Optics express.

[177]  Manoj K. Arora,et al.  Study of water cloud model vegetation descriptors in estimating soil moisture in Solani catchment , 2015 .

[178]  Lu Dong,et al.  Validation of the AIEM Through Correlation Length Parameterization at Field Scale Using Radar Imagery in a Semi-Arid Environment , 2013, IEEE Geoscience and Remote Sensing Letters.

[179]  Paolo Ferrazzoli,et al.  L-Band Passive and Active Signatures of Vegetated Soil: Simulations With a Unified Model , 2016, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.

[180]  Mehrez Zribi,et al.  New methodology for soil surface moisture estimation and its application to ENVISAT-ASAR multi-incidence data inversion , 2005 .

[181]  Thomas J. Jackson,et al.  Soil moisture mapping at regional scales using microwave radiometry: the Southern Great Plains Hydrology Experiment , 1999, IEEE Trans. Geosci. Remote. Sens..

[182]  S. Seneviratne,et al.  Investigating soil moisture-climate interactions in a changing climate: A review , 2010 .

[183]  H. E. Garrett,et al.  Soil water content and infiltration in agroforestry buffer strips , 2008, Agroforestry Systems.

[184]  Joan Girona,et al.  Differential irrigation scheduling by an automated algorithm of water balance tuned by capacitance-type soil moisture sensors , 2020 .

[185]  Kun-Shan Chen,et al.  Radar Scattering and Imaging of Rough Surfaces , 2020 .

[186]  F. Baret,et al.  MARMIT: A multilayer radiative transfer model of soil reflectance to estimate surface soil moisture content in the solar domain (400–2500 nm) , 2018, Remote Sensing of Environment.

[187]  J. Adegoke,et al.  Relations between Soil Moisture and Satellite Vegetation Indices in the U.S. Corn Belt , 2002 .

[188]  Quan Chen,et al.  Method for Soil Moisture and Surface Temperature Estimation in the Tibetan Plateau Using Spaceborne Radiometer Observations , 2015, IEEE Geoscience and Remote Sensing Letters.

[189]  Rasmus Fensholt,et al.  Combining the triangle method with thermal inertia to estimate regional evapotranspiration — Applied to MSG-SEVIRI data in the Senegal River basin , 2008 .

[190]  Thuy Le Toan,et al.  Dependence of radar backscatter on coniferous forest biomass , 1992, IEEE Trans. Geosci. Remote. Sens..

[191]  Jiancheng Shi,et al.  Tests of the SMAP Combined Radar and Radiometer Algorithm Using Airborne Field Campaign Observations and Simulated Data , 2014, IEEE Transactions on Geoscience and Remote Sensing.

[192]  Xiaoxiang Zhu,et al.  Multisensor Data Fusion for Cloud Removal in Global and All-Season Sentinel-2 Imagery , 2020, IEEE Transactions on Geoscience and Remote Sensing.

[193]  He Li,et al.  Soil moisture estimation based on the microwave scattering mechanism during different crop phenological periods in a winter wheat-producing region , 2020 .

[194]  A. Al Bitar,et al.  Global-scale evaluation of two satellite-based passive microwave soil moisture datasets (SMOS and AMSR-E) with respect to Land Data Assimilation System estimates , 2014, Remote Sensing of Environment.

[195]  Seung-Bum Kim,et al.  Soil Moisture Retrieval Using L-Band Radar Observations , 2015, IEEE Transactions on Geoscience and Remote Sensing.

[196]  Jean-Pierre Wigneron,et al.  A parameterized multifrequency-polarization surface emission model , 2005, IEEE Transactions on Geoscience and Remote Sensing.

[197]  Wolfgang Wagner,et al.  Analytical solution for first-order scattering in bistatic radiative transfer interaction problems of layered media. , 2016, Applied optics.

[198]  Marouane Temimi,et al.  Using microwave brightness temperature diurnal cycle to improve emissivity retrievals over land , 2012 .

[199]  S. Fabre,et al.  Influence of soil moisture content on spectral reflectance of bare soils in the 0.4–14 μm domain , 2013 .

[200]  Zhao-Liang Li,et al.  Bare surface soil moisture retrieval from the synergistic use of optical and thermal infrared data , 2014 .

[201]  G. Petropoulos,et al.  A review of Ts/VI remote sensing based methods for the retrieval of land surface energy fluxes and soil surface moisture , 2009 .

[202]  S. Jones,et al.  The optical trapezoid model: A novel approach to remote sensing of soil moisture applied to Sentinel-2 and Landsat-8 observations , 2017 .

[203]  N. Chauhan,et al.  Soil moisture estimation under a vegetation cover: Combined active passive microwave remote sensing approach , 1997 .

[204]  A. Abdellaoui,et al.  Use of Meteosat for Mapping Thermal Inertia and Evapotranspiration over a Limited Region of Mali , 1986 .

[205]  F. Ulaby,et al.  Textural Infornation in SAR Images , 1986, IEEE Transactions on Geoscience and Remote Sensing.

[206]  Ronglin Tang,et al.  Estimation of Soil Evaporation and Vegetation Transpiration Using Two Trapezoidal Models From MODIS Data , 2019, Journal of Geophysical Research: Atmospheres.

[207]  Kun-Shan Chen,et al.  Radar Response of Off-Specular Bistatic Scattering to Soil Moisture and Surface Roughness at L-Band , 2016, IEEE Geoscience and Remote Sensing Letters.

[208]  Kun-Shan Chen,et al.  A Comprehensive Analysis of Rough Soil Surface Scattering and Emission Predicted by AIEM With Comparison to Numerical Simulations and Experimental Measurements , 2017, IEEE Transactions on Geoscience and Remote Sensing.

[209]  H. Kaufmann,et al.  Surface soil moisture quantification models from reflectance data under field conditions , 2008 .

[210]  Robert H. Woodward,et al.  Determining Soil Moisture from Geosynchronous Satellite Infrared Data: A Feasibility Study , 1984 .

[211]  R. Horton,et al.  A general approach to estimate soil water content from thermal inertia , 2009 .

[212]  W. Kustas,et al.  A verification of the 'triangle' method for obtaining surface soil water content and energy fluxes from remote measurements of the Normalized Difference Vegetation Index (NDVI) and surface e , 1997 .

[213]  M. Piles,et al.  Simultaneous retrieval of global scale Vegetation Optical Depth, surface roughness, and soil moisture using X-band AMSR-E observations , 2019 .

[214]  Marisa B. Domenech,et al.  Prediction of topsoil properties at field-scale by using C-band SAR data , 2020, Int. J. Appl. Earth Obs. Geoinformation.

[215]  S. Jones,et al.  A linear physically-based model for remote sensing of soil moisture using short wave infrared bands , 2015 .

[216]  Michael C. Dorf,et al.  Why some things are darker when wet. , 1988, Applied optics.

[217]  Anne B. Kahle,et al.  A simple thermal model of the Earth's surface for geologic mapping by remote sensing , 1977 .

[218]  Urs Wegmüller,et al.  Observing and Modeling Multifrequency Scattering of Maize During the Whole Growth Cycle , 2008, IEEE Transactions on Geoscience and Remote Sensing.

[219]  Brian W. Barrett,et al.  Soil Moisture Retrieval from Active Spaceborne Microwave Observations: An Evaluation of Current Techniques , 2009, Remote. Sens..

[220]  Kun-Shan Chen,et al.  Theoretical Study of Global Sensitivity Analysis of L-Band Radar Bistatic Scattering for Soil Moisture Retrieval , 2018, IEEE Geoscience and Remote Sensing Letters.

[221]  Martha C. Anderson,et al.  Development of soil moisture profiles through coupled microwave–thermal infrared observations in the southeastern United States , 2017, Hydrology and Earth System Sciences.

[222]  R. Scott,et al.  Coupling diffusion and maximum entropy models to estimate thermal inertia , 2012 .

[223]  Michael H. Cosh,et al.  Assessment and Validation of AirMOSS P-Band Root-Zone Soil Moisture Products , 2020, IEEE Transactions on Geoscience and Remote Sensing.

[224]  T. Carlson An Overview of the “Triangle Method” for Estimating Surface Evapotranspiration and Soil Moisture from Satellite Imagery , 2007, Sensors (Basel, Switzerland).

[225]  T. Mo,et al.  A model for microwave emission from vegetation‐covered fields , 1982 .

[226]  T. Jackson,et al.  Use of active and passive microwave remote sensing for soil moisture estimation through corn , 1996 .

[227]  Zhao-Liang Li,et al.  A practical approach for deriving all-weather soil moisture content using combined satellite and meteorological data , 2017 .

[228]  Xingfa Gu,et al.  Evaluation of methods for soil surface moisture estimation from reflectance data , 2003 .

[229]  Niko E. C. Verhoest,et al.  A review of spatial downscaling of satellite remotely sensed soil moisture , 2017 .

[230]  Zhao-Liang Li,et al.  Sensitivity study of soil moisture on the temporal evolution of surface temperature over bare surfaces , 2013 .

[231]  Jean-Pierre Wigneron,et al.  Physically Based Estimation of Bare-Surface Soil Moisture With the Passive Radiometers , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[232]  Imen Gherboudj,et al.  Soil moisture retrieval over agricultural fields from multi-polarized and multi-angular RADARSAT-2 SAR data , 2011 .

[233]  J. Zawadzki,et al.  Modification of the Land Surface Temperature – Vegetation Index Triangle Method for soil moisture condition estimation by using SYNOP reports , 2020 .

[234]  Yong Xue,et al.  Thermal inertia determination from space— a tutorial review , 1996 .

[235]  T. Jackson,et al.  III. Measuring surface soil moisture using passive microwave remote sensing , 1993 .

[236]  H. Franssen,et al.  Soil hydrology: Recent methodological advances, challenges, and perspectives , 2015 .

[237]  W. Verstraeten,et al.  Soil moisture retrieval using thermal inertia, determined with visible and thermal spaceborne data, validated for European forests , 2006 .

[238]  Catherine Champagne,et al.  Impact of Soil Moisture Data Characteristics on the Sensitivity to Crop Yields Under Drought and Excess Moisture Conditions , 2019, Remote. Sens..

[239]  Austin M. Jensen,et al.  Assessment of Surface Soil Moisture Using High-Resolution Multi-Spectral Imagery and Artificial Neural Networks , 2015, Remote. Sens..

[240]  Jasmeet Judge,et al.  Response of Subdaily L-Band Backscatter to Internal and Surface Canopy Water Dynamics , 2020, IEEE Transactions on Geoscience and Remote Sensing.

[241]  A. Stogryn,et al.  The Brightness Temperature of a Vertically Structured Medium , 1970 .

[242]  E. Njoku,et al.  Vegetation and surface roughness effects on AMSR-E land observations , 2006 .

[243]  Y. Kerr,et al.  State of the Art in Large-Scale Soil Moisture Monitoring , 2013 .

[244]  Xavier Briottet,et al.  Estimation of Soil Moisture Content from the Spectral Reflectance of Bare Soils in the 0.4–2.5 μm Domain , 2015, Sensors.

[245]  Keith P. B. Thomson,et al.  Adaptation of the MIMICS backscattering model to the agricultural context-wheat and canola at L and C bands , 1994, IEEE Trans. Geosci. Remote. Sens..

[246]  W. Wagner,et al.  Global-scale assessment and combination of SMAP with ASCAT (active) and AMSR2 (passive) soil moisture products , 2017 .

[247]  Ronglin Tang,et al.  An End-Member-Based Two-Source Approach for Estimating Land Surface Evapotranspiration From Remote Sensing Data , 2017, IEEE Transactions on Geoscience and Remote Sensing.

[248]  Jeffrey P. Walker,et al.  A methodology for surface soil moisture and vegetation optical depth retrieval using the microwave polarization difference index , 2001, IEEE Trans. Geosci. Remote. Sens..

[249]  P. Doraiswamy,et al.  Relationship between satellite microwave radiometric data, antecedent precipitation index, and regional soil moisture , 1993 .

[250]  Jun Asanuma,et al.  Thermal Inertia Approach Using a Heat Budget Model to Estimate the Spatial Distribution of Surface Soil Moisture over a Semiarid Grassland in Central Mongolia , 2017 .

[251]  Nazzareno Pierdicca,et al.  Soil moisture estimation over vegetated terrains using multitemporal remote sensing data. , 2010 .

[252]  Huifang Li,et al.  An effective thin cloud removal procedure for visible remote sensing images , 2014 .

[253]  Jiancheng Shi,et al.  The Soil Moisture Active Passive (SMAP) Mission , 2010, Proceedings of the IEEE.

[254]  F. Ulaby,et al.  Microwave Dielectric Behavior of Wet Soil-Part II: Dielectric Mixing Models , 1985, IEEE Transactions on Geoscience and Remote Sensing.

[255]  W. Dorigo,et al.  Surface Soil Moisture Estimation : Significance, Controls and Conventional Measurement Techniques , 2013 .

[256]  Thomas J. Jackson,et al.  WindSat Global Soil Moisture Retrieval and Validation , 2010, IEEE Transactions on Geoscience and Remote Sensing.

[257]  Samuel N. Goward,et al.  Observed relation between thermal emission and reflected spectral radiance of a complex vegetated landscape , 1985 .

[258]  Eric F. Wood,et al.  Four decades of microwave satellite soil moisture observations: Part 1. A review of retrieval algorithms , 2017 .

[259]  Yann Kerr,et al.  Towards Soil Moisture Retrieval Using Tower-Based P-Band Radiometer Observations , 2018, IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium.

[260]  M. I. L'vovich,et al.  World Fresh Water Resources , 2013 .

[261]  N. Baghdadi,et al.  Impact of polarization and incidence of the ASAR sensor on coastline mapping: example of Gabon , 2007 .

[262]  Qin Li,et al.  Emission of rough surfaces calculated by the integral equation method with comparison to three-dimensional moment method simulations , 2003, IEEE Trans. Geosci. Remote. Sens..

[263]  Hongjie Xie,et al.  Estimating root zone soil moisture at distant sites using MODIS NDVI and EVI in a semi-arid region of southwestern USA , 2010, Ecol. Informatics.

[264]  Kamal Sarabandi,et al.  An empirical model and an inversion technique for radar scattering from bare soil surfaces , 1992, IEEE Trans. Geosci. Remote. Sens..

[265]  M. Hosseini,et al.  Soil moisture estimation by using multipolarization SAR image , 2011 .

[266]  Saibun Tjuatja,et al.  Numerical simulation of scattering from three-dimensional randomly rough surfaces , 1994, IEEE Trans. Geosci. Remote. Sens..

[267]  Arnaud Mialon,et al.  SMOS-IC: Current Status and Overview of Soil Moisture and VOD Applications , 2018, IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium.

[268]  G. Salvucci,et al.  Empirical evidence of contrasting soil moisture–precipitation feedbacks across the United States , 2016, Science.

[269]  R. Magagi,et al.  Soil moisture retrievals using ALOS2-ScanSAR and MODIS synergy over Tibetan Plateau , 2020 .

[270]  Xiliang Ni,et al.  Retrieving Surface Soil Moisture over Wheat and Soybean Fields during Growing Season Using Modified Water Cloud Model from Radarsat-2 SAR Data , 2019, Remote. Sens..

[271]  J. Kong,et al.  Theory for passive microwave remote sensing of near‐surface soil moisture , 1977 .

[272]  M. Zribi,et al.  A new empirical model to retrieve soil moisture and roughness from C-band radar data , 2003 .

[273]  W. Wagner,et al.  A Method for Estimating Soil Moisture from ERS Scatterometer and Soil Data , 1999 .

[274]  Roger D. De Roo,et al.  A semi-empirical backscattering model at L-band and C-band for a soybean canopy with soil moisture inversion , 2001, IEEE Trans. Geosci. Remote. Sens..