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In this paper, we propose a new approach for improving boreal forest soil moisture estimation using L-band microwave radiometer. The effect is achieved by introducing improved description of forest canopy contribution from multisensor SAR measurements.
The Soil Moisture Active Passive (SMAP) mission, launched January 31, 2015, provides global observations of 1.4 GHz Earth thermal emissions from space [1] through its L-band radiometer. Although SMAP's radiometer passband lies within the protected 1.4–1.427 GHz band, both unauthorized in-band transmitters as well as out-of-band emissions from transmitters operating at frequencies adjacent to this...
Surface soil moisture was retrieved globally by systematically correcting for the effects of vegetation and soil surface roughness. The retrieval is enabled by employing physical-models of radar forward scattering for individual vegetation types to account for vegetation scattering and absorption, and by constraining the surface roughness effect using time-series observations. The L-band SMAP multi-polarized...
Soil moisture is one of the important variables in hydrological systems. Spatial and temporal dynamics of soil moisture are important for determining complex environmental process. The aim of the study is to assess the trend of soil moisture in India and to monitor agricultural drought in Medak district of Telangana state during the period 2002 to 2014. Spatio-temporal analysis has been performed...
We have concluded that before calculation of the AirMOSS project overall RMSE, not only the behavior and location of in-situ soil moisture probes need to be carefully evaluated but also the present error biases—associated with the in-situ probes, radar calibration, vegetation parameterization, forward model inaccuracy, and the inversion algorithm bias—need to be removed. Several measures have been...
Estimation of vertical ground displacements due to seasonal periods of freezing and thawing was carried out on the Selenga River mouth using differential radar interferometry. The results of seasonal radar interferometry measurements for 2008–2010 have been compared with the survey data for 2011, under the assumption that the seasonal deformation is comparable for different years and lie within the...
Remotely sensed soil moisture data can provide timely, objective and quantitative crop soil moisture information with broad geospatial coverage and sufficiently high resolution observations collected throughout the growing season. This paper evaluates the feasibility of using the assimilated ESA Soil Moisture Ocean Salinity (SMOS) Mission L-band passive microwave data for operational US cropland soil...
The distorted Born approximation (DBA) combined with the numerical solutions of Maxwell equations (NMM3D) has been used for the radar backscattering model for NASA's Soil Moisture Active Passive (SMAP) mission. The models for vegetated surfaces such as wheat, grass, soybean and corn have been validated with the Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12) data. In this paper...
Scanning L-band Active/Passive (SLAP) is an airborne remote sensing instrument developed at NASA Goddard Space Flight Center specifically as an airborne simulator of the Soil Moisture Active/Passive (SMAP) satellite instrument suite, for remote sensing of soil moisture, freeze-thaw state, ocean salinity, sea ice, and other physical phenomena that display characteristics at microwave L-band. This paper...
Groundwater is an important component of the hydrological cycle. In Canada, more than 30% of the population relies on groundwater as the main source of water for domestic use. However, its measurement and monitoring remain challenging at large spatial scales. In this study, we examined the relationship between in situ groundwater data extracted from existing wells, and those derived from the Gravity...
An experiment to examine the detectability of volcanic ash cover and its thickness by using L-band synthetic aperture radar (SAR) was carried out. Test sites with 0, 10, 20, and 40 cm ash layers were developed. PALSAR-2 and Pi-SAR-L2 observations were carried out several times with and without the ash cover. The PALSAR-2 backscatter coefficients in HH polarization, σHH0, for soil with ash layers are...
State of the art soil moisture radar retrieval algorithms traditionally depend on substantial amounts of ancillary data, such as land cover and soil texture/composition maps, to parametrize complex electromagnetic models. In this work, we pursue an existing empirical approach as an alternative; it expresses radar backscatter of a vegetated scene as a linear function of soil moisture, thus reducing...
Drought is widely distributed in the world, resulting in the shortage of water resources, decreasing groundwater storage, reducing yields of crops, and sustained severe drought even cause serious social and economic problems that affect people's life. Based on the drought monitoring theory and remote sensing data, the drought assessment in Beijing-Tianjin-Hebei(JJJ) region from 2005 to 2014 have been...
The main objective of this study is to develop an inversion technique based on neural networks to estimate soil surface moisture and leaf area index (LAI) in irrigated grasslands by combining fully polarimetric RADARSAT-2 C-band SAR and optical data (LANDSAT). The benefits of having data in dual-polarization or in full-polarization mode for the SAR images were evaluated in comparison to the single-polarization...
Soil moisture measurements are important for disciplines such as hydrology, climatology and agriculture. GNSS Reflectometry (GNSS-R) technique has been demonstrated to be an effective tool to sense soil moisture content (SMC). Besides airborne observations, great efforts have also been made concerning ground-based measurements. However, those methods are either based on too many hypotheses or depend...
Surface soil moisture (SSM) is a significant variable in various fields of science. This paper aims to analyze and improve a SSM retrieval model to apply it to estimate SSM at the regional scale. Firstly, the model parameters were been analyzed. The rotation angle was transformed into exponential form and the ellipse center horizontal coordinate was decreased for the improved SSM retrieval model....
Improved soil moisture estimation, within a combined radar-radiometer framework, by using Joint-physics modeling is demonstrated and presented in this work. Detailed numerical simulation on bare, but rough surfaces, highlight how improved emission-scattering modeling, can outperform conventional approaches. Root-mean-squared error statistics show almost a factor of two improvement in soil permittivity...
Soil moisture is a key variable in the exchange of water and energy between the land surface and atmosphere, especially over the Tibetan Plateau. The Fengyun-3B Microwave Radiation Imager (FY-3B/MWRI) soil moisture product is one of relatively new passive microwave products. This paper validated the FY-3B/MWRI soil moisture product using in-suit measurements within two soil moisture networks (1°×1°...
In this study, we used a multilinear regression approach to retrieve surface soil moisture from NASA's Soil Moisture Active Passive (SMAP) satellite data to create a global dataset of surface soil moisture which is consistent with ESA's Soil Moisture and Ocean Salinity (SMOS) satellite retrieved surface soil moisture. This was achieved by calibrating coefficients of the regression model using SMOS...
In this paper, the soil moisture content (SMC) estimated from Advanced Microwave Scanning Radiometer 2 (AMSR2) through the ANN-based “HydroAlgo” algorithm is firstly compared with the outputs of the Soil Water Balance hydrological model (SWBM). The comparison is performed over Italy, by considering all the available overpasses of AMSR2, since July 2012. The SMC generated by Hydroalgo is then considered...
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