Calibration of the Water Cloud Model at C-Band for Winter Crop Fields and Grasslands

In a perspective to develop an inversion approach for estimating surface soil moisture of crop fields from Sentinel-1/2 data (radar and optical sensors), the Water Cloud Model (WCM) was calibrated from C-band Synthetic Aperture Radar (SAR) data and Normalized Difference Vegetation Index (NDVI) values collected over crops fields and grasslands. The soil contribution that depends on soil moisture and surface roughness (in addition to SAR instrumental parameters) was simulated using the physical backscattering model IEM (Integral Equation Model). The vegetation descriptor used in the WCM is the NDVI because it can be directly calculated from optical images. A large dataset consisting of radar backscattered signal in Vertical transmit and Vertical receive (VV) and Vertical transmit and Horizontal receive (VH) polarizations with wide range of incidence angle, soil moisture, surface roughness, and NDVI-values was used. It was collected over two agricultural study sites. Results show that the soil contribution to the total radar backscattered signal is lower in VH than in VV because VH is more sensitive to vegetation cover. Thus, the use of VH alone or in addition to VV for retrieving the soil moisture is not advantageous in presence of well-developed vegetation cover.

[1]  Gérard Dedieu,et al.  Combined use of FORMOSAT-2 images with a crop model for biomass and water monitoring of permanent grassland in Mediterranean region , 2010 .

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

[3]  G. Guyot,et al.  Estimating surface soil moisture and leaf area index of a wheat canopy using a dual-frequency (C and X bands) scatterometer , 1993 .

[4]  B. Duchemin,et al.  Combined use of optical and radar satellite data for the monitoring of irrigation and soil moisture of wheat crops , 2011 .

[5]  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.

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

[7]  Xiaojing Bai,et al.  A Synergistic Methodology for Soil Moisture Estimation in an Alpine Prairie Using Radar and Optical Satellite Data , 2014, Remote. Sens..

[8]  Frédéric Baup,et al.  Analysis of TerraSAR-X data sensitivity to bare soil moisture, roughness, composition and soil crust , 2011 .

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

[10]  N. Baghdadi,et al.  Soil moisture retrieval over irrigated grassland using X-band SAR data , 2016 .

[11]  Mehrez Zribi,et al.  Use of TerraSAR-X Data to Retrieve Soil Moisture Over Bare Soil Agricultural Fields , 2012, IEEE Geoscience and Remote Sensing Letters.

[12]  A. Chehbouni,et al.  Soil surface moisture estimation over a semi-arid region using ENVISAT ASAR radar data for soil evaporation evaluation , 2011 .

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

[14]  Ian G. Cumming,et al.  A modified empirical model for soil moisture estimation in vegetated areas using SAR data , 2004, IGARSS 2004. 2004 IEEE International Geoscience and Remote Sensing Symposium.

[15]  Mehrez Zribi,et al.  Potential of X-Band TerraSAR-X and COSMO-SkyMed SAR Data for the Assessment of Physical Soil Parameters , 2015, Remote. Sens..

[16]  Mehdi Hosseini,et al.  Soil moisture estimation based on integration of optical and SAR images , 2011 .

[17]  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..

[18]  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.

[19]  Shaun Quegan,et al.  High-resolution measurements of scattering in wheat canopies-implications for crop parameter retrieval , 2003, IEEE Trans. Geosci. Remote. Sens..

[20]  Martha C. Anderson,et al.  Upscaling ground observations of vegetation water content, canopy height, and leaf area index during SMEX02 using aircraft and Landsat imagery , 2004 .

[21]  Thuy Le Toan,et al.  Multitemporal C-band radar measurements on wheat fields , 2003, IEEE Transactions on Geoscience and Remote Sensing.

[22]  N. Baghdadi,et al.  Estimation of soil parameters over bare agriculture areas from C-band polarimetric SAR data using neural networks , 2012 .

[23]  Mehrez Zribi,et al.  Irrigated Grassland Monitoring Using a Time Series of TerraSAR-X and COSMO-SkyMed X-Band SAR Data , 2014, Remote. Sens..

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

[25]  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.

[26]  Marco Schwerdt,et al.  Independent System Calibration of Sentinel-1B , 2017, Remote. Sens..

[27]  Dharmendra Singh,et al.  A Fusion Approach to Retrieve Soil Moisture With SAR and Optical Data , 2012, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.

[28]  Mehrez Zribi,et al.  Calibration of the Integral Equation Model for SAR data in C‐band and HH and VV polarizations , 2006 .

[29]  Mehrez Zribi,et al.  Toward an Operational Bare Soil Moisture Mapping Using TerraSAR-X Data Acquired Over Agricultural Areas , 2013, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.

[30]  Mehrez Zribi,et al.  Soil moisture mapping based on ASAR/ENVISAT radar data over a Sahelian region , 2007 .

[31]  Mehrez Zribi,et al.  Analysis of Sentinel-1 Radiometric Stability and Quality for Land Surface Applications , 2016, Remote. Sens..

[32]  Frédéric Baup,et al.  A New Empirical Model for Radar Scattering from Bare Soil Surfaces , 2016, Remote. Sens..

[33]  Christophe Sannier,et al.  Estimating Surface Soil Moisture from TerraSAR-X Data over Two Small Catchments in the Sahelian Part of Western Niger , 2011, Remote. Sens..

[34]  Eric Pottier,et al.  A Potential Use for the C-Band Polarimetric SAR Parameters to Characterize the Soil Surface Over Bare Agriculture Fields , 2012, IEEE Transactions on Geoscience and Remote Sensing.

[35]  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.