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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - A Modified Scattering Model of Row Wheat at X-Band
摘要： Cereal crops, contrary to natural vegetation, have the different characteristics for their regular planting. Further, the random assumption of the radiative transfer theory is not suitable for cereal canopy. The paper aimed to present a modified scattering model of row wheat at X-band (center frequency 3.2GHz). The modified scattering model considered both the surface scattering of soil and the volume scattering of wheat canopy. In different wheat growth stage, the weights of the two kinds of scattering phenomenon were set up based on an empirical growth model because of their visible area. A series of data including wheat growth parameters and backscatter coefficients, related to the interaction, were collected for the analyses of the model. The research results showed the model could better reflect the scattering phenomenon of regulate planting, which is helpful to agriculture remote sensing fields.
关键词： scatterometer,vegetation,soil,Modeling,backscatter
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - The “Urban Geomatics for Bulk Information Generation, Data Assessment and Technology Awareness” Project: Detection, Representation and Analysis of the Urban Scenario Changes
摘要： About 54% of world population nowadays lives in urban areas and this percentage is expected to increase up to 66% by 2050. Therefore, it is crucial to manage this social and cultural change by collecting, integrating and sharing reliable and open spatial information concerning the urban environments where we leave in. The present availability of huge archives of synthetic aperture radar (SAR) data collected since 1992 by ESA, in conjunction with the available Earth-Observation (EO) optical data, represents a unique possibility to derive valuable information for the understanding of the ongoing urban processes. In this framework, the three-year project financed by the Italian Ministry of Instruction, Research and University, entitled “URBAN GEOmatics for bulk information generation, data assessment and technology awareness” may play a role for the assessment and the development of new replicable methodologies for the study of soil consumption and mobility in urban zones. The paper aims to present some preliminary results achieved during the project, clarifying how the new emerging technologies for managing big EO data are proficient for the investigation of urban processes.
关键词： InSAR,Urban areas,soil consumption
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Smos Retrievals of Soil Freezing and Thawing and its Applications
摘要： The Finnish Meteorological Institute, together with Gamma Remote Sensing, Switzerland, has developed a global soil freeze/thaw detection algorithm using passive L-band microwave observations from the European Space Agency’s Soil Moisture and Ocean Salinity (SMOS) mission. The current product gives the soil state as “frozen”, “partially frozen”, or “thawed”. Estimates for a given season are derived after each winter period. An operational product with a latency of one day is under development. Global information on soil freezing and thawing has many applications; e.g. in evaluation or as an input prior in carbon and climate models, soil carrying capacity analysis, and hydrological models.
关键词： soil freeze/thaw,L-band,SMOS,carbon cycle
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - SMOS-IC: Current Status and Overview of Soil Moisture and VOD Applications
摘要： In 2017, the new SMOS-IC retrieval product of soil moisture (SM) and L-band Vegetation Optical depth (L-VOD) was developed. This product relies on a two-parameter inversion of the L-MEB model (L-band Microwave Emission of the Biosphere) which requires little ancillary information and was found to be accurate, making it very well-suited for application in agriculture, hydrology, climate and vegetation monitoring. In this communication we present recent improvements in the SMOS-IC retrieval algorithm and recent applications using the soil moisture or VOD retrievals from the SMOS-IC data set. SMOS-IC SM is available at the French CATDS center.
关键词： carbon stocks,biomass,SMOS,VOD,SMOS-IC,soil moisture
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Geophysical Relationship between Cygnss GNSS-R Bistatic Reflectivity and Smap Microwave Radiometry Brightness Temperature Over Land Surfaces
摘要： This work presents an assessment on the correlation between CyGNSS-derived Global Navigation Satellite Systems Reflectometry (GNSS-R) bistatic reflectivity rl? and SMAP-derived brightness temperature BT, over land surfaces. This parametric-study is performed as a function of Soil Moisture Content (SMC), and vegetation opacity τ. Several target areas are selected to evaluate potential differentiated geophysical effects on “active” (as many transmitters as navigation satellites are in view), and passive approaches. Although microwave radiometry has potentially a better sensitivity to SMC, the spatial resolution is poor ~ 40 km. On the other hand, GNSS-R bistatic coherent radar footprint is limited by half of the first Fresnel zone which provides about ~ 150 m of spatial resolution (depending on the geometry). The synergetic combination of both techniques could provide advantages with respect to active monostatic Synthetic Aperture Radar (SAR).
关键词： vegetation opacity,CyGNSS,GNSS-R,land,microwave radiometry,SMAP,multi-static radar,Soil Moisture Content (SMC)
更新于2025-09-10 09:29:36
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A GA-based stacking algorithm for predicting soil organic matter from vis-NIR spectral data
摘要： It has been demonstrated that diffuse reflectance spectroscopy in the visible and near-infrared (vis–NIR) can be exploited to predict chemical and physical soil properties. Immense soil spectral libraries (SSL) are being developed, therefore more elaborate tools that capitalize on contemporary knowledge and techniques need to be established to provide accurate predictions. In this paper, we propose a novel genetic algorithm-based stacking model that makes synergetic use of multiple models developed from different pre-processed spectral sources (termed L1 models). This is a form of ensemble learning where multiple hypotheses are combined to create a more robust and more accurate ensemble hypothesis. The genetic algorithm automatically defines the configuration of the stacked model, by selecting the best cooperating subset of the initial models. Our methodology was tested on the newly developed GEO-CRADLE SSL to predict soil organic matter (SOM). Results showed that the accuracy of prediction of the proposed method ( =0.76, and ratio of performance to inter quartile range RPIQ=2.22) was better than the one attained by the best L1 model ( =0.65, RPIQ=1.93). This approach can thus be effectively utilized to enhance the predictions of soil properties in small and large soil spectral libraries alike.
关键词： model stacking,North Africa,GEO-CRADLE,vis–NIR spectroscopy,soil spectroscopy,Middle East,Balkans
更新于2025-09-10 09:29:36
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Mapping Soil Alkalinity and Salinity in Northern Songnen Plain, China with the HJ-1 Hyperspectral Imager Data and Partial Least Squares Regression
摘要： In arid and semi-arid regions, identifying and monitoring of soil alkalinity and salinity are in urgently need for preventing land degradation and maintaining ecological balances. In this study, physicochemical, statistical, and spectral analysis revealed that potential of hydrogen (pH) and electrical conductivity (EC) characterized the saline-alkali soils and were sensitive to the visible and near infrared (VIS-NIR) wavelengths. On the basis of soil pH, EC, and spectral data, the partial least squares regression (PLSR) models for estimating soil alkalinity and salinity were constructed. The R2 values for soil pH and EC models were 0.77 and 0.48, and the root mean square errors (RMSEs) were 0.95 and 17.92 dS/m, respectively. The ratios of performance to inter-quartile distance (RPIQ) for the soil pH and EC models were 3.84 and 0.14, respectively, indicating that the soil pH model performed well but the soil EC model was not considerably reliable. With the validation dataset, the RMSEs of the two models were 1.06 and 18.92 dS/m. With the PLSR models applied to hyperspectral data acquired from the hyperspectral imager (HSI) onboard the HJ-1A satellite (launched in 2008 by China), the soil alkalinity and salinity distributions were mapped in the study area, and were validated with RMSEs of 1.09 and 17.30 dS/m, respectively. These findings revealed that the hyperspectral images in the VIS-NIR wavelengths had the potential to map soil alkalinity and salinity in the Songnen Plain, China.
关键词： alkalinity and salinity,PLSR model,hyperspectral data,soil
更新于2025-09-10 09:29:36
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Determination of hydrological roughness by means of close range remote sensing
摘要： The objective of the presented work was to develop a method to acquire Manning’s n by creating very high-resolution surface models with structure-from-motion methods. As hydraulic roughness is an essential parameter for physically based erosion models, a practical measuring technique is valuable during field work. Data acquisition took place during several field experiments in the Lainbach valley, southern Germany, and on agricultural sites in Saxony, eastern Germany, and in central Brazil. Rill and interrill conditions were simulated by flow experiments. In order to validate our findings stream velocity was measured with colour tracers. Grain sizes were derived by measuring distances from a best fit line to the reconstructed soil surface. Several diameters from D50 to D90 were tested with D90 showing best correlation between tracer experiments and photogrammetrically acquired data. Several roughness parameters were tested (standard deviation, random roughness, Garbrecht’s n and D90). Best agreement in between the grain size and the hydraulic roughness was achieved with a non-linear sigmoid function and D90 rather than with the Garbrecht equation or statistical parameters.
关键词： soil erosion models,hydrological roughness,close range remote sensing,Manning’s n,structure-from-motion
更新于2025-09-10 09:29:36
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Vegetation Optical Depth and Soil Moisture Retrieved from L-Band Radiometry over the Growth Cycle of a Winter Wheat
摘要： L-band radiometer measurements were performed at the Selhausen remote sensing field laboratory (Germany) over the entire growing season of a winter wheat stand. L-band microwave observations were collected over two different footprints within a homogenous winter wheat stand in order to disentangle the emissions originating from the soil and from the vegetation. Based on brightness temperature (TB) measurements performed over an area consisting of a soil surface covered by a reflector (i.e., to block the radiation from the soil surface), vegetation optical depth (τ) information was retrieved using the tau-omega (τ-ω) radiative transfer model. The retrieved τ appeared to be clearly polarization dependent, with lower values for horizontal (H) and higher values for vertical (V) polarization. Additionally, a strong dependency of τ on incidence angle for the V polarization was observed. Furthermore, τ indicated a bell-shaped temporal evolution, with lowest values during the tillering and senescence stages, and highest values during flowering of the wheat plants. The latter corresponded to the highest amounts of vegetation water content (VWC) and largest leaf area index (LAI). To show that the time, polarization, and angle dependence is also highly dependent on the observed vegetation species, white mustard was grown during a short experiment, and radiometer measurements were performed using the same experimental setup. These results showed that the mustard canopy is more isotropic compared to the wheat vegetation (i.e., the τ parameter is less dependent on incidence angle and polarization). In a next step, the relationship between τ and in situ measured vegetation properties (VWC, LAI, total of aboveground vegetation biomass, and vegetation height) was investigated, showing a strong correlation between τ over the entire growing season and the VWC as well as between τ and LAI. Finally, the soil moisture was retrieved from TB observations over a second plot without a reflector on the ground. The retrievals were significantly improved compared to in situ measurements by using the time, polarization, and angle dependent τ as a priori information. This improvement can be explained by the better representation of the vegetation layer effect on the measured TB.
关键词： inverse modeling,SMOS,vegetation optical depth,microwave remote sensing,SMAP,soil moisture,winter wheat,tower-based experiment
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Comparison of Different High-Resolution Soil Moisture Products Across an Agricultural Landscape in South-Eastern Australia
摘要： A number of satellite missions have the capability to provide surface soil moisture information at a range of spatial and temporal scales. However, the validation of such products heavily relies on point measurements from permanent stations, which may or may not be representative of the larger scale soil moisture conditions. Hence, methods need to be developed that allow the sampling of surface soil moisture on the ground across large scales over a reasonably short time scale, in order to capture the spatial variability within a footprint, or to provide spatially sufficiently large data sets to validate high-resolution products, be they at their native resolution or downscaled. In this study, two field-scale ground sampling techniques, namely stationary and roving Cosmic Ray Probes, are compared against a high-resolution satellite product. The data are compared for their temporal performance as well as with a focus on capturing the correct spatial variability. The challenge is the inherently different sensing depth of the various technologies. It is shown that this may largely be overcome through scaling the products.
关键词： Soil moisture,satellite product validation,cosmic ray probe
更新于2025-09-10 09:29:36