Estimating soil moisture at the watershed scale with satellite-based radar and land surface models

Spatially distributed soil moisture profiles are required for watershed applications such as drought and flood prediction, crop irrigation scheduling, pest management, and determining mobility with lightweight vehicles. Satellite-based soil moisture can be obtained from passive microwave, active microwave, and optical sensors, although the coarse spatial resolution of passive microwave and the inability to obtain vertically resolved information from optical sensors limit their usefulness for watershed-scale applications. Active microwave sensors such as synthetic aperture radar (SAR) currently represent the best approach for obtaining spatially distributed surface soil moisture at scales of 10–100 m for watersheds ranging from 1 000 to 25 000 km2. Although SAR provides surface soil moisture, the applications listed above require vertically resolved soil moisture profiles. To obtain distributed soil moisture profiles, a combined approach of calibration and data assimilation in soil vegetation atmosphere transfer (SVAT) models based on recent advances in soil physics is the most promising avenue of research. This review summarizes the state of the science using current satellite-based sensors to determine watershed-scale surface soil moisture distribution and the state of combining SVAT models with data assimilation and calibration approaches for the estimation of profile soil moisture. The basic conclusion of this review is that currently orbiting SAR sensors combined with available SVAT models could provide distributed profile soil moisture information with known accuracy at the watershed scale. The priority areas for future research should include image-based approaches for mapping surface roughness, determination of soil moisture in densely vegetated sites, active and passive microwave data fusion, and joint calibration and data assimilation approaches for a combined remote sensing – modeling system. For validation, a worldwide in situ soil moisture monitoring program should be implemented. Finally, to realize the full potential of satellite-based soil moisture estimation for watershed applications, it will be necessary to continue sensor development, improve image availability and timely delivery, and reduce image cost.

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

[2]  T. Schmugge.  Remote Sensing of Surface Soil Moisture , 1978 .

[3]  H. Pan,et al.  A two-layer model of soil hydrology , 1984 .

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

[5]  Richard K. Moore,et al.  Radar remote sensing and surface scattering and emission theory , 1986 .

[6]  A. Dalcher,et al.  A Simple Biosphere Model (SIB) for Use within General Circulation Models , 1986 .

[7]  Charlotte Steinmeier,et al.  The SIR-B Observations of Microwave Backscatter Dependence on Soil Moisture, Surface Roughness, and Vegetation Covers , 1986, IEEE Transactions on Geoscience and Remote Sensing.

[8]  Ann Henderson-Sellers,et al.  Biosphere-atmosphere Transfer Scheme (BATS) for the NCAR Community Climate Model , 1986 .

[9]  H. Pan,et al.  Interaction between soil hydrology and boundary-layer development , 1987 .

[10]  R. Pelletier,et al.  Response to soil moisture of spectral indexes derived from bidirectional reflectance in Thematic Mapper wavebands , 1988 .

[11]  F. Ulaby,et al.  Handbook of radar scattering statistics for terrain , 1989 .

[12]  Piers J. Sellers,et al.  A Simplified Biosphere Model for Global Climate Studies , 1991 .

[13]  Bhaskar J. Choudhury,et al.  Analysis of normalized difference and surface temperature observations over southeastern Australia , 1991 .

[14]  S. Sorooshian,et al.  Effective and efficient global optimization for conceptual rainfall‐runoff models , 1992 .

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

[16]  Kamal Sarabandi,et al.  Preliminary analysis of ERS-1 SAR for forest ecosystem studies , 1992, IEEE Trans. Geosci. Remote. Sens..

[17]  A. Fung,et al.  Dependence of the surface backscattering coefficients on roughness, frequency and polarization states , 1992 .

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

[19]  Behavior of AIRSAR signals during MAC-EUROPE'91 , 1993, Proceedings of IGARSS '93 - IEEE International Geoscience and Remote Sensing Symposium.

[20]  R. Dickinson,et al.  The Project for Intercomparison of Land Surface Parameterization Schemes (PILPS): Phases 2 and 3 , 1993 .

[21]  Ann Henderson-Sellers,et al.  Biosphere-atmosphere transfer scheme(BATS) version 1e as coupled to the NCAR community climate model , 1993 .

[22]  Extraction of soil moisture from multitemporal, ERS-1 SLC data of the Freiburg test-site , 1993, Proceedings of IGARSS '93 - IEEE International Geoscience and Remote Sensing Symposium.

[23]  L. Prévot,et al.  Estimating the characteristics of vegetation canopies with airborne radar measurements , 1993 .

[24]  S. Running,et al.  Developing Satellite-derived Estimates of Surface Moisture Status , 1993 .

[25]  F. R. Schiebe,et al.  Large area mapping of soil moisture using the ESTAR passive microwave radiometer , 1995 .

[27]  E. T. Engman.  The potential of SAR in hydrology , 1994, Proceedings of IGARSS '94 - 1994 IEEE International Geoscience and Remote Sensing Symposium.

[28]  Raghavan Srinivasan,et al.  INTEGRATION OF A BASIN‐SCALE WATER QUALITY MODEL WITH GIS , 1994 .

[29]  D. Lettenmaier,et al.  A simple hydrologically based model of land surface water and energy fluxes for general circulation models , 1994 .

[30]  M. Friedl,et al.  Sources of variation in radiometric surface temperature over a tallgrass prairie , 1994 .

[31]  Dara Entekhabi,et al.  Solving the inverse problem for soil moisture and temperature profiles by sequential assimilation of multifrequency remotely sensed observations , 1994, IEEE Trans. Geosci. Remote. Sens..

[32]  Eric F. Wood,et al.  Application of multiscale water and energy balance models on a tallgrass prairie , 1994 .

[33]  Scott A. Isard,et al.  A Soil Moisture Climatology of Illinois , 1994 .

[34]  J. Famiglietti,et al.  Multiscale modeling of spatially variable water and energy balance processes , 1994 .

[35]  Garrison Sposito,et al.  Recent advances associated with soil water in the unsaturated zone (95RG00280) , 1995 .

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

[37]  E. Engman,et al.  Status of microwave soil moisture measurements with remote sensing , 1995 .

[38]  Kun Shan Chen,et al.  A simple model for retrieving bare soil moisture from radar-scattering coefficients , 1995 .

[39]  Robert M. Rabin,et al.  Regional‐scale comparisons of vegetation and soil wetness with surface energy budget properties from satellite and in‐situ observations , 1995 .

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

[41]  Ann Henderson-Sellers,et al.  The Project for Intercomparison of Land Surface Parameterization Schemes (PILPS): Phases 2 and 3 , 1995 .

[42]  V. Singh,et al.  Computer Models of Watershed Hydrology , 1995 .

[43]  Peter A. Troch,et al.  Evaluation of surface soil moisture distribution by means of SAR remote sensing techniques and conceptual hydrological modelling , 1995 .

[44]  Tobias Wever,et al.  Evaluation of the AIRSAR system for soil moisture analysis , 1995 .

[45]  Dennis McLaughlin,et al.  Recent developments in hydrologic data assimilation , 1995 .

[46]  Ya-Qiu Jin,et al.  A simple method to estimate the soil wetness and surface roughness by using active/passive microwave data , 1995 .

[47]  Yann Kerr,et al.  Geographical, biological and remote sensing aspects of the hydrologic atmospheric pilot experiment in the sahel (HAPEX-Sahel) , 1995 .

[48]  André Chanzy,et al.  Soil evaporation monitoring: a possible synergism of microwave and infrared remote sensing , 1995 .

[49]  T. Carlson,et al.  Thermal remote sensing of surface soil water content with partial vegetation cover for incorporation into climate models , 1995 .

[50]  D. Vidal-Madjar,et al.  Taking into account vegetation effects to estimate soil moisture from C-band radar measurements , 1996 .

[51]  Thomas J. Schmugge,et al.  Applications of passive microwave observations of surface soil moisture , 1996, IGARSS '96. 1996 International Geoscience and Remote Sensing Symposium.

[52]  D. Randall,et al.  A Revised Land Surface Parameterization (SiB2) for Atmospheric GCMS. Part I: Model Formulation , 1996 .

[53]  M. S. Dawson,et al.  A modified IEM model for: scattering from soil surfaces with application to soil moisture sensing , 1996, IGARSS '96. 1996 International Geoscience and Remote Sensing Symposium.

[54]  A. Henderson‐sellers,et al.  Validation of soil moisture simulation in landsurface parameterisation schemes with HAPEX data , 1996 .

[55]  C. Justice,et al.  A Revised Land Surface Parameterization (SiB2) for Atmospheric GCMS. Part II: The Generation of Global Fields of Terrestrial Biophysical Parameters from Satellite Data , 1996 .

[56]  D. Lettenmaier,et al.  Surface soil moisture parameterization of the VIC-2L model: Evaluation and modification , 1996 .

[57]  Eric F. Lambin,et al.  The surface temperature-vegetation index space for land cover and land-cover change analysis , 1996 .

[58]  F. Ulaby,et al.  Radar mapping of surface soil moisture , 1996 .

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

[60]  Y. Xue,et al.  Modeling of land surface evaporation by four schemes and comparison with FIFE observations , 1996 .

[61]  M. S. Moran,et al.  Combining multifrequency microwave and optical data for crop management , 1997 .

[62]  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 .

[63]  Y. Kerr,et al.  Soil moisture estimation under sparse vegetation using microwave radiometry at C-band , 1997, IGARSS'97. 1997 IEEE International Geoscience and Remote Sensing Symposium Proceedings. Remote Sensing - A Scientific Vision for Sustainable Development.

[64]  S. Goward,et al.  Estimation of air temperature from remotely sensed surface observations , 1997 .

[65]  Eric F. Wood,et al.  A soil‐vegetation‐atmosphere transfer scheme for modeling spatially variable water and energy balance processes , 1997 .

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

[67]  B. Brisco,et al.  Effect of surface soil moisture gradients on modelling radar backscattering from bare fields , 1997 .

[68]  R. Gillies.  A verification of the 'triangle' method for obtaining surface water content and energy fluxes from remote measurements of Normalized Difference Vegetation Index (NDVI) and surface radiant temperature , 1997 .

[69]  Jiancheng Shi,et al.  A Comparison of Soil Moisture Retrieval Models Using SIR-C Measurements over the Little Washita River Watershed , 1997 .

[70]  Wim G.M. Bastiaanssen,et al.  Area-average estimates of evaporation, wetness indicators and top soil moisture during two golden days in EFEDA , 1997 .

[71]  K. Mitchell,et al.  Impact of Atmospheric Surface-layer Parameterizations in the new Land-surface Scheme of the NCEP Mesoscale Eta Model , 1997 .

[72]  Randal D. Koster,et al.  The Interplay between Transpiration and Runoff Formulations in Land Surface Schemes Used with Atmospheric Models , 1997 .

[73]  S. Sarkar,et al.  Calibration of a water uptake simulation model under varying soil moisture regime and nitrogen level for wheat crop , 1997 .

[74]  F. Mattia,et al.  On the retrieval of soil moisture from SAR data over bare soils , 1997, IGARSS'97. 1997 IEEE International Geoscience and Remote Sensing Symposium Proceedings. Remote Sensing - A Scientific Vision for Sustainable Development.

[75]  Jiancheng Shi,et al.  Estimation of bare surface soil moisture and surface roughness parameter using L-band SAR image data , 1997, IEEE Trans. Geosci. Remote. Sens..

[76]  John R. Williams,et al.  LARGE AREA HYDROLOGIC MODELING AND ASSESSMENT PART I: MODEL DEVELOPMENT 1 , 1998 .

[77]  Yoshio Inoue,et al.  Ku- and C-band SAR for discriminating agricultural crop and soil conditions , 1998, IEEE Trans. Geosci. Remote. Sens..

[78]  Scott T. Acton,et al.  Automated segmentation of surface soil moisture from Landsat TM data , 1998, 1998 IEEE Southwest Symposium on Image Analysis and Interpretation (Cat. No.98EX165).

[79]  J. Wigneron,et al.  Estimation of energy fluxes and photosynthesis from thermal infrared, spectral reflectances, microwave data and SVAT modeling , 1998, IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174).

[80]  Soroosh Sorooshian,et al.  Multi-objective global optimization for hydrologic models , 1998 .

[81]  Jean-Christophe Calvet,et al.  Retrieving the Root-Zone Soil Moisture from Surface Soil Moisture or Temperature Estimates: A Feasibility Study Based on Field Measurements , 1998 .

[82]  Bruce G. Colpitts,et al.  The integral equation model and surface roughness signatures in soil moisture and tillage type determination , 1998, IEEE Trans. Geosci. Remote. Sens..

[83]  A. Weimann.  Inverting a microwave backscattering model by the use of a neural network for the estimation of soil moisture , 1998, IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174).

[84]  Ground-based microwave radiometer measurements during the Southern Great Plains '97 experiment , 1998, IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174).

[85]  Thomas J. Jackson,et al.  Microwave remote sensing of soil moisture for estimation of profile soil property , 1998 .

[86]  M. S. Moran,et al.  Relation between ERS‐1 synthetic aperture radar data and measurements of surface roughness and moisture content of rocky soils in a semiarid rangeland , 1998 .

[87]  K. Schneider,et al.  The determination of mesoscale soil moisture patterns with ERS data , 1998, IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174).

[88]  W. J. Shuttleworth,et al.  Integration of soil moisture remote sensing and hydrologic modeling using data assimilation , 1998 .

[89]  A. J. Dolman,et al.  The Pilot Phase of the Global Soil Wetness Project , 1999 .

[90]  M. Borgeaud,et al.  Status of the retrieval of bio- and geo-physical parameters from SAR data for land applications , 1999, IEEE 1999 International Geoscience and Remote Sensing Symposium. IGARSS'99 (Cat. No.99CH36293).

[91]  S. Beldringa,et al.  Distribution of soil moisture and groundwater levels at patch and catchment scales , 1999 .

[92]  Dara Entekhabi,et al.  Tests of sequential data assimilation for retrieving profile soil moisture and temperature from observed L-band radiobrightness , 1999, IEEE Trans. Geosci. Remote. Sens..

[94]  J. E. Lewis,et al.  A moisture index for surface characterization over a semiarid area , 1999 .

[95]  R. Lang,et al.  Passive and active microwave remote sensing of soil moisture under a forest canopy , 1999, IEEE 1999 International Geoscience and Remote Sensing Symposium. IGARSS'99 (Cat. No.99CH36293).

[96]  M. Ashby.  Modelling the water and energy balances of Amazonian rainforest and pasture using Anglo-Brazilian Amazonian climate observation study data , 1999 .

[97]  Soil moisture variability on the landscape as a function of land use: implication for remote sensing of surface soil moisture , 1999, IEEE 1999 International Geoscience and Remote Sensing Symposium. IGARSS'99 (Cat. No.99CH36293).

[98]  Ravi Kothari,et al.  Spatial characterization of remotely sensed soil moisture data using self organizing feature maps , 1999, IEEE Trans. Geosci. Remote. Sens..

[99]  Fabio Castelli,et al.  Estimation of surface heat flux and an index of soil moisture using adjoint‐state surface energy balance , 1999 .

[100]  Dirk H. Hoekman,et al.  Radar backscatter inversion techniques for estimation of surface soil moisture: EFEDA-Spain and HAPEX-Sahel case studies , 1999, IEEE Trans. Geosci. Remote. Sens..

[101]  Jean-Christophe Calvet,et al.  From Near-Surface to Root-Zone Soil Moisture Using Year-Round Data , 2000 .

[102]  N. Floury,et al.  On the soil moisture retrieval of bare soils with ERS SAR data , 2000, IGARSS 2000. IEEE 2000 International Geoscience and Remote Sensing Symposium. Taking the Pulse of the Planet: The Role of Remote Sensing in Managing the Environment. Proceedings (Cat. No.00CH37120).

[103]  George Mason,et al.  Development of a fast all-seasons model for the state of the ground , 2000, 2000 Winter Simulation Conference Proceedings (Cat. No.00CH37165).

[104]  P. Curran,et al.  The relationship between ERS-2 SAR backscatter and soil moisture: Generalization from a humid to semi-arid transect , 2000 .

[105]  Jean-Pierre Wigneron,et al.  Estimation of Watershed Soil Moisture Index from ERS/SAR Data , 2000 .

[106]  M. S. Moran,et al.  Soil moisture evaluation using multi-temporal synthetic aperture radar (SAR) in semiarid rangeland , 2000 .

[107]  Klaus Scipal,et al.  Large-scale soil moisture mapping in western Africa using the ERS scatterometer , 2000, IEEE Trans. Geosci. Remote. Sens..

[108]  A. Robock,et al.  The Global Soil Moisture Data Bank , 2000 .

[109]  F.P. De Troch,et al.  Soil moisture inversion from ERS and SIR-C imagery at the Zwalm catchment, Belgium , 2000, IGARSS 2000. IEEE 2000 International Geoscience and Remote Sensing Symposium. Taking the Pulse of the Planet: The Role of Remote Sensing in Managing the Environment. Proceedings (Cat. No.00CH37120).

[110]  Yisok Oh.  Retrieval of the effective soil moisture contents as a ground truth from natural soil surfaces , 2000, IGARSS 2000. IEEE 2000 International Geoscience and Remote Sensing Symposium. Taking the Pulse of the Planet: The Role of Remote Sensing in Managing the Environment. Proceedings (Cat. No.00CH37120).

[111]  Yang Du,et al.  Sensitivity to soil moisture by active and passive microwave sensors , 2000, IEEE Trans. Geosci. Remote. Sens..

[112]  Samuel N. Goward,et al.  Thermal Remote Sensing of Near Surface Environmental Variables: Application Over the Oklahoma Mesonet , 2000 .

[113]  G. Bouleta,et al.  A simple water and energy balance model designed for regionalization and remote sensing data utilization , 2000 .

[114]  D. McLaughlin,et al.  Variational data assimilation of soil moisture and temperature from remote sensing observations. , 2000 .

[116]  Peter Troch,et al.  Assimilation of active microwave observation data for soil moisture profile estimation , 2000 .

[117]  Giorgio Boni,et al.  Land data assimilation with satellite measurements for the estimation of surface energy balance components and surface control on evaporation , 2001 .

[118]  Giorgio Boni,et al.  Sampling strategies and assimilation of ground temperature for the estimation of surface energy balance components , 2001, IEEE Trans. Geosci. Remote. Sens..

[119]  Multi-parameter airborne SAR remote sensing of soil moisture in agricultural area , 2001, IGARSS 2001. Scanning the Present and Resolving the Future. Proceedings. IEEE 2001 International Geoscience and Remote Sensing Symposium (Cat. No.01CH37217).

[120]  C. Notarnicola,et al.  Bayesian fusion of active and passive microwave data for estimating bare soil water content , 2001, IGARSS 2001. Scanning the Present and Resolving the Future. Proceedings. IEEE 2001 International Geoscience and Remote Sensing Symposium (Cat. No.01CH37217).

[121]  Peter Troch,et al.  Directives for 4-D soil moisture data assimilation in hydrological modelling , 2001 .

[122]  M. S. Moran,et al.  Coupling a grassland ecosystem model with Landsat imagery for a 10-year simulation of carbon and water budgets , 2001 .

[123]  Rajat Bindlish,et al.  Parameterization of vegetation backscatter in radar-based, soil moisture estimation , 2001 .

[124]  Eric F. Wood,et al.  A re-examination of modeled and measured soil moisture spatial variability and its implications for land surface modeling , 2001 .

[125]  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..

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

[127]  Thomas J. Jackson,et al.  Multitemporal monitoring of soil moisture with RADARSAT sar during the 1997 Southern Great Plains hydrology experiment , 2001 .

[128]  Jetse D. Kalma,et al.  One-dimensional soil moisture profile retrieval by assimilation of near-surface observations: a comparison of retrieval algorithms , 2001 .

[129]  K. Stankiewicz,et al.  Various approaches for soil moisture estimates using remote sensing , 2001, IGARSS 2001. Scanning the Present and Resolving the Future. Proceedings. IEEE 2001 International Geoscience and Remote Sensing Symposium (Cat. No.01CH37217).

[130]  Paul R. Houser,et al.  A methodology for initializing soil moisture in a global climate model: Assimilation of near‐surface soil moisture observations , 2001 .

[131]  D. McLaughlin,et al.  Downscaling of radio brightness measurements for soil moisture estimation: A four‐dimensional variational data assimilation approach , 2001 .

[132]  Yann Kerr,et al.  Directional effect on radiative surface temperature measurements over a semiarid grassland site , 2001 .

[133]  D. Entekhabi,et al.  Land data assimilation and estimation of soil moisture using measurements from the Southern Great Plains 1997 Field Experiment , 2001 .

[134]  Thomas J. Jackson,et al.  Soil moisture and TRMM microwave imager relationships in the Southern Great Plains 1999 (SGP99) experiment , 2001, IEEE Trans. Geosci. Remote. Sens..

[135]  Investigating the potential for soil moisture and surface roughness monitoring in drylands using ERS SAR data , 2001 .

[136]  J. Font,et al.  The objectives and rationale of the Soil Moisture and Ocean Salinity (SMOS) mission , 2001, IGARSS 2001. Scanning the Present and Resolving the Future. Proceedings. IEEE 2001 International Geoscience and Remote Sensing Symposium (Cat. No.01CH37217).

[137]  Rolf Reichle,et al.  Variational data assimilation of microwave radiobrightness observations for land surface hydrology applications , 2001, IEEE Trans. Geosci. Remote. Sens..

[138]  Jetse D. Kalma,et al.  One-Dimensional Soil Moisture Profile Retrieval by Assimilation of Near-Surface Measurements: A Simplified Soil Moisture Model and Field Application , 2001 .

[139]  Zhiming Lu,et al.  Study of high SAR backscattering caused by an increase of soil moisture over a sparsely vegetated area: Implications for characteristics of backscattering , 2002 .

[140]  N. Baghdadi,et al.  Retrieving surface roughness and soil moisture from synthetic aperture radar (SAR) data using neural networks , 2002 .

[141]  J. Wigneron,et al.  An empirical calibration of the integral equation model based on SAR data, soil moisture and surface roughness measurement over bare soils , 2002 .

[142]  Jeffrey P. Walker,et al.  Extended versus Ensemble Kalman Filtering for Land Data Assimilation , 2002 .

[143]  Thomas J. Jackson,et al.  Soil moisture retrieval using the C-band polarimetric scanning radiometer during the Southern Great Plains 1999 Experiment , 2002, IEEE Trans. Geosci. Remote. Sens..

[144]  Thomas R. Gatliffe,et al.  Calibration and Reliability in Groundwater Modelling: Coping with Uncertainty , 2002, Technometrics.

[145]  Dennis McLaughlin,et al.  An integrated approach to hydrologic data assimilation: interpolation, smoothing, and filtering , 2002 .

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

[147]  Wade T. Crow,et al.  The Value of Coarse-Scale Soil Moisture Observations for Regional Surface Energy Balance Modeling , 2002 .

[148]  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 .

[149]  Rajat Bindlish,et al.  Subpixel variability of remotely sensed soil moisture: an inter-comparison study of SAR and ESTAR , 2002, IEEE Trans. Geosci. Remote. Sens..

[150]  Priroda microwave radiometer observations in the Southern Great Plains 1997 hydrology experiment , 2002 .

[151]  Christophe François,et al.  The potential of directional radiometric temperatures for monitoring soil and leaf temperature and soil moisture status , 2002 .

[152]  Gerald N. Flerchinger,et al.  Intercode comparisons for simulating water balance of surficial sediments in semiarid regions , 2002 .

[153]  Jan Feyen,et al.  Use of sensitivity and uncertainty measures in distributed hydrological modeling with an application to the MIKE SHE model , 2002 .

[154]  Wade T. Crow,et al.  Impact of Soil Moisture Aggregation on Surface Energy Flux Prediction During SGP'97 , 2002 .

[155]  A. Karnieli,et al.  Mapping of several soil properties using DAIS-7915 hyperspectral scanner data - a case study over clayey soils in Israel , 2002 .

[156]  D. McLaughlin,et al.  Hydrologic Data Assimilation with the Ensemble Kalman Filter , 2002 .

[157]  Ana P. Barros,et al.  Downscaling of remotely sensed soil moisture with a modified fractal interpolation method using contraction mapping and ancillary data , 2002 .

[158]  F. Baret,et al.  Relating soil surface moisture to reflectance , 2002 .

[159]  Gwangseob Kim,et al.  Space-time characterization of soil moisture from passive microwave remotely sensed imagery and ancillary data , 2002 .

[160]  Thomas J. Jackson,et al.  Soil moisture retrieval from AMSR-E , 2003, IEEE Trans. Geosci. Remote. Sens..

[161]  Jirka Òimçnek,et al.  Using the HYDRUS-1 D and HYDRUS-2 D Codes for Estimating Unsaturated Soil Hydraulic and Solute Transport Parameters , 2003 .

[162]  Lifeng Luo,et al.  An intercomparison of soil moisture fields in the North American Land Data Assimilation System (NLDAS) , 2003 .

[163]  Witold F. Krajewski,et al.  An analysis of small-scale rainfall variability in different climatic regimes , 2003 .

[164]  Modelling the water and energy balances of Amazonian rainforest and pasture , 2003 .

[165]  W. Crow,et al.  The assimilation of remotely sensed soil brightness temperature imagery into a land surface model using Ensemble Kalman filtering: a case study based on ESTAR measurements during SGP97 , 2003 .

[166]  T. D. Potter,et al.  Handbook of weather, climate, and water : atmospheric chemistry, hydrology, and societal impacts , 2003 .

[167]  R. Koster,et al.  Assessing the Impact of Horizontal Error Correlations in Background Fields on Soil Moisture Estimation , 2003 .

[168]  J. D. Tarpley,et al.  The multi‐institution North American Land Data Assimilation System (NLDAS): Utilizing multiple GCIP products and partners in a continental distributed hydrological modeling system , 2004 .

[169]  Jiaguo Qi,et al.  Soil moisture estimation in a semiarid rangeland using ERS-2 and TM imagery , 2004 .

[170]  Ross Bryant,et al.  Comparison of two methods for extracting surface soil moisture from C-band radar imagery , 2004, IGARSS 2004. 2004 IEEE International Geoscience and Remote Sensing Symposium.

[171]  M. Sahebi,et al.  Semi-empirical calibration of the IEM backscattering model using radar images and moisture and roughness field measurements , 2004 .

[172]  Jeffrey P. Walker,et al.  THE GLOBAL LAND DATA ASSIMILATION SYSTEM , 2004 .

[173]  Jean Rousselle,et al.  Mapping near‐surface soil moisture with RADARSAT‐1 synthetic aperture radar data , 2004 .

[174]  Anthony J. Jakeman,et al.  Model development for integrated assessment of water allocation options , 2004 .

[175]  Soroosh Sorooshian,et al.  Dual state-parameter estimation of hydrological models using ensemble Kalman filter , 2005 .

[176]  Soroosh Sorooshian,et al.  Constraining Land Surface and Atmospheric Parameters of a Locally Coupled Model Using Observational Data , 2005 .

[177]  Jitendra Behari,et al.  Microwave dielectric behavior of wet soils , 2005 .