The objective of the study was to estimate soil moisture (SM) from Sentinel-1 (S-1) satellite images acquired over wetlands. The study was carried out during the years 2015–2017 in the Biebrza ...Wetlands, situated in north-eastern Poland. At the Biebrza Wetlands, two Sentinel-1 validation sites were established, covering grassland and marshland biomes, where a network of 18 stations for soil moisture measurement was deployed. The sites were funded by the European Space Agency (ESA), and the collected measurements are available through the International Soil Moisture Network (ISMN). The SAR data of the Sentinel-1 satellite with VH (vertical transmit and horizontal receive) and VV (vertical transmit and vertical receive) polarization were applied to SM retrieval for a broad range of vegetation and soil moisture conditions. The methodology is based on research into the effect of vegetation on backscatter (σ°) changes under different soil moisture and Normalized Difference Vegetation Index (NDVI) values. The NDVI was derived from the optical imagery of a MODIS (Moderate Resolution Imaging Spectroradiometer) sensor onboard the Terra satellite. It was found that the state of the vegetation expressed by NDVI can be described by the indices such as the difference between σ° VH and VV, or the ratio of σ° VV/VH, as calculated from the Sentinel-1 images in the logarithmic domain. The most significant correlation coefficient for soil moisture was found for data that was acquired from the ascending tracks of the Sentinel-1 satellite, characterized by the lowest incidence angle, and SM at a depth of 5 cm. The study demonstrated that the use of the inversion approach, which was applied to the newly developed models using Water Cloud Model (WCM) that includes the derived indices based on S-1, allowed the estimation of SM for wetlands with reasonable accuracy (10 vol. %). The developed soil moisture retrieval algorithms based on S-1 data are suited for wetland ecosystems, where soil moisture values are several times higher than in agricultural areas.
The objectives of the study were to determine the spatial rate of CO2 flux (Net Ecosystem Exchange) and soil moisture in a wetland ecosystem applying Sentinel-1 IW (Interferometric Wide) data of VH ...(Vertical Transmit/Horizontal Receive—cross polarization) and VV (Vertical Transmit/Vertical Receive—like polarization) polarization. In-situ measurements of carbon flux, soil moisture, and LAI (Leaf Area Index) were carried out over the Biebrza Wetland in north-eastern Poland. The impact of soil moisture and LAI on backscattering coefficient (σ°) calculated from Sentinel-1 data showed that LAI dominates the influence on σ° when soil moisture is low. The models for soil moisture have been derived for wetland vegetation habitat types applying VH polarization (R2 = 0.70 to 0.76). The vegetation habitats: reeds, sedge-moss, sedges, grass-herbs, and grass were classified using combined one Landsat 8 OLI (Operational Land Imager) and three TerraSAR-X (TSX) ScanSAR VV data. The model for the assessment of Net Ecosystem Exchange (NEE) has been developed based on the assumption that soil moisture and biomass represented by LAI have an influence on it. The σ° VH and σ° VV describe soil moisture and LAI, and have been the input to the NEE model. The model, created for classified habitats, is as follows: NEE = f (σ° Sentinel-1 VH, σ° Sentinel-1 VV). Reasonably good predictions of NEE have been achieved for classified habitats (R2 = 0.51 to 0.58). The developed model has been used for mapping spatial and temporal distribution of NEE over Biebrza wetland habitat types. Eventually, emissions of CO2 to the atmosphere (NEE positive) has been noted when soil moisture (SM) and biomass were low. This study demonstrates the importance of the capability of Sentinel-1 microwave data to calculate soil moisture and estimate NEE with all-weather acquisition conditions, offering an important advantage for frequent wetlands monitoring.
The aim of the study was to elaborate the remote sensing methods for monitoring wetlands ecosystems. The investigation was carried out during the years 2002-2010 in the Biebrza Wetlands. The ...meteorological conditions at the test site varied from extremely dry to very wet. The authors propose applying satellite remote sensing data acquired in the optical and microwave spectrums to classify wetlands vegetation habitats for the assessment of vegetation changes and estimation of wetlands' biophysical properties to improve monitoring of these unique, very often physically impenetrable, areas. The backscattering coefficients ( sigma degree ) calculated from ALOS PALSAR FBD (Advanced Land Observing Satellite, Phased Array type L-band Synthetic Aperture Radar, Fine Beam Dual Mode) images registered at cross polarization HV on 12 May 2008 were used to classify the main wetland communities using ground truth observations and the visual interpretation method. As a result, the sigma degree values were distributed among the six wetlands' vegetation classes: scrubs, sedges-scrubs, sedges, reeds, sedges-reeds, rushes, and the areas of each community and changes were assessed. Also, the change in the biophysical variable as Leaf Area Index (LAI) is described using the information from PALSAR data. Strong linear relationships have been found between LAI and sigma degree derived for particular wetland classes, which then were applied to elaborate the maps of LAI distribution. The other variables used to characterize the changing environmental conditions are: surface temperature (Ts) calculated from NOAA AVHRR (National Oceanic and Atmospheric Administration Advanced Very High Resolution Radiometer) and Normalized Difference Vegetation Index (NDVI) from ENVISAT MERIS (ENVIronmental SATellite MEdium Resolution Imaging Spectrometer). Differences of almost double Ts between "dry" and "wet" years were noticed that reflect observed weather conditions. The highest values of NDVI occurred in years with a sufficient amount of precipitation with the lowest in "dry" years. NDVI values variances within the same wetlands class resulted mainly from the differences in soil moisture. The results of this study show that the satellite data from microwave and optical spectrum gave the repetitive spatial information about vegetation growth conditions and could be used for monitoring wetland ecosystems.
Biophysical Parameters Assessed from Microwave and Optical Data The study has been carried out at Biebrza Wetlands situated in the N-E part of Poland, a NATURA 2000 and Ramsar Convention test site in ...2003-2009. It is one of the largest in Europe natural rich biotope with the large amount of unique species of flora and important zone for nesting and wintering for fauna. Data from microwave and optical satellite images and soil-vegetation ground measurements were analyzed to develop methods for monitoring and mapping biophysical parameters. Satellite data applied for the study included: ENVISAT.ASAR, ENVISAT.MERIS, ALOS.PALSAR, ALOS.AVNIR-2, and NOAA.AVHRR data. Optical images were used for classification of wetlands communities and calculation of vegetation index NDVI. Also, latent heat flux has been calculated using NOAA.AVHRR data and meteorological data. Microwave images acquired in different modes (ASAR IS2 and IS6, ALPSR.FBD) and polarizations (HH, HV, VV) were used for assessment and mapping of Leaf Area Index (LAI) and soil moisture (SM) for every habitat classified from optical images. Backscattering coefficient calculated from ALOS.PALSAR HV and ENVISAT.ASAR IS6 VV was applied for assessment of vegetation bio-parameters. Backscattering coefficient calculated from ALOS.PALSAR.FBD HH and ENVISAT.ASAR HH IS2 was used for SM assessment. The study was conducted in the framework of ESA PECS project No 98101 and ESA PI projects: C1P.7389 and AOALO.3742.
The Remote Sensing Centre in the Institute of Geodesy and Cartography has undertaken the investigation of applying ENVISAT.ASAR, ALOS.PALSAR, and TerraSAR-X data for modelling of soil moisture under ...various crops. Radar data are independent of weather conditions and that is why they are very useful in monitoring the dynamic of various soil–vegetation parameters. The aim of the study was to examine the usefulness of radar data for describing the soil–vegetation parameters of agri-environment ecosystem in the Wielkopolska region of Poland. The research on agriculture area has been carried out at ground level by taking measurements of soil moisture, Leaf Area Index, height of the vegetation, and wet and dry biomass. The TerraSAR-X and ALOS.PALSAR images have been applied for classification of agriculture area. The images taken in X band were used for discriminating the structure of vegetation, while the images taken in L-band turned out to be very effective at mapping structure of forests and distinguishing them from non-forest areas. Therefore synergy of images acquired in bands X and L gave good results in classification of forested areas and crops. The influence of soil moisture on backscattering coefficient calculated from ENVISAT.ASAR under various polarisations and incidence angles for different crops distinguished from classification of ENVISAT.ASAR IS6 and IS4 has been examined to find correlations between satellite derived data and soil–vegetation parameters. The best correlation between backscatter and LAI has been obtained by applying ASAR IS6 HH or ASAR IS4 HH images, while the best correlation between backscatter and soil moisture has been obtained applying ASAR IS6 VV or ASAR IS4 VV images. The influence of the crop descriptor such as LAI on backscatter coefficient calculated from ENVISAT.ASAR IS2 HH under various soil moisture conditions as well as the influence of the crop descriptor such as soil moisture on backscatter coefficient calculated from ENVISAT.ASAR IS2 HV under various LAI conditions was examined for wheat using the “water-cloud model”. The relationships between modelled values of soil moisture and LAI and measured values have been derived and discussed.
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Provider: - Institution: - Data provided by Europeana Collections- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain ...Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
This study was conducted during 2003-2009 in Biebrza Wetlands, a NATURA 2000 and Ramsar Convention test site situated in Northeast Poland. It is one of the largest in Europe natural rich biotope with ...the large amount of unique spices of flora and important zone for nesting and wintering for fauna. Protection of wetlands that are very sensitive ecosystems are of great importance in nature conservation for carbon and water cycles. Changes of soil water content affect plant cover and lead to elimination or preference of certain species. Controlling soil moisture is essential for protection of peat-forming plant communities and slow down drying processes against mineralization and carbon exhaust. Data from optical and microwave satellite images and soil-vegetation ground measurements were analyzed to develop methods for monitoring and mapping soil-vegetation parameters over wetlands. This study was conducted in the framework of national grant N N526021733 and ESA projects AOID.122 and AOALO.3742.
Nature has always been a source of inspiration for the development of novel materials and devices. In particular, polymer actuators that mimic the movements and functions of natural organisms have ...been of great interest due to their potential applications in various fields, such as biomedical engineering, soft robotics, and energy harvesting. During recent years, the development and actuation performance of electrospun fibrous meshes with the advantages of high permeability, surface area, and easy functional modification, has received extensive attention from researchers. This review covers the recent progress in the state-of-the-art electrospun actuators based on commonly used polymers such as stimuli-sensitive hydrogels, shape-memory polymers (SMPs), and electroactive polymers. The design strategies inspired by nature such as hierarchical systems, layered structures, and responsive interfaces to enhance the performance and functionality of these actuators, including the role of biomimicry to create devices that mimic the behavior of natural organisms, are discussed. Finally, the challenges and future directions in the field, with a focus on the development of more efficient and versatile electrospun polymer actuators which can be used in a wide range of applications, are addressed. The insights gained from this review can contribute to the development of advanced and multifunctional actuators with improved performance and expanded application possibilities.
The presented research focuses on the synthesis and structure–properties relationship of poly(carbonate-urea-urethane) (PCUU) systems including investigations on shape-memory effect capability. ...Furthermore, we approached the topic from a broader perspective by conducting extensive analysis of the relationship between the synthesized compounds and the results of computer simulations by means of the Monte Carlo method. For the first time, by using a unique simulation tool, the dynamic lattice liquid model (DLL), all steps of multi-step synthesis of these materials were covered by the simulations. Furthermore, broad thermal, mechanical, and thermomechanical characterization of synthesized PCUUs was performed, as well as determining the shape-memory properties. PCUUs exhibited good mechanical properties with a tensile strength above 20 MPa, elongation at break around 800%, and an exhibited shape-memory effect with shape fixity and shape recovery ratios above 94% and 99%, respectively. The dynamic lattice liquid model was employed to show the products and their molar mass distribution, as well as monomer conversion or the dispersity index for individual reaction steps. The results obtained in the following manuscript allow the planning of syntheses for the PCUUs of various structures, including crosslinked and soluble systems, which can provide a broad variety of applications of these materials, as well as a better understanding of the composition–properties relationship.
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