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Geometric Aspects of Detecting Grassland Mowing in Krkonoše Mountains Based on Sentinel-1 Coherence
Dvořák, Jakub ; Potůčková, Markéta (advisor) ; Mouratidis, Antonios (referee)
Grassland mowing is a common management practice used in European grasslands for livestock fodder production and to enhance biodiversity. To support a less intensive use of grasslands, public agencies look for a reliable way to monitor the management performed on the grasslands. Satellite remote sensing is a key tool for monitoring over large areas, with SAR remote sensing being especially useful in areas with high cloud cover. However, grassland monitoring using SAR in complex terrain is not fully understood and may come with challenges related to topography and sensor geometry. To explore these potential challenges, this thesis detected mowing events using a high-resolution DEM for precise coregistration and terrain correction of Sentinel-1 SAR imagery. Effect of local incidence angle on detection accuracy from interferometric coherence was also explored. The hypotheses were tested on 61 grassland plots in Krkonoše mountains, Czechia. Detection accuracies in this thesis were higher than in previous studies when only considering SAR detections. The improvement was most likely caused by counting detections from individual orbits to assess the certainty of each detection. A deeper analysis showed that using a high-resolution DEM led to a horizontal shift in computed coherence, but the shift had no...
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Using Sentinel-1 data for creating a digital terrain model by means of radar interferometry
Karvánek, Matouš ; Potůčková, Markéta (advisor) ; Hlaváčová, Ivana (referee)
Using of Sentinel-1 data for radar interferometry Abstract The diploma thesis deals with extraction of a digital surface model (DSM) using synthetic aperture radar interferometry (InSAR) and Sentinel-1 data in selected locations of the Czech Republic. The InSAR technique, the Sentinel-1 data, their parameters and possibilities of their usage are described in the theoretical part of the thesis. The specification of the model areas and used data follows. The practical part is focused on creating a methodology of deriving a digital surface model and its extracting in the three tested locations. These locations differ from each other in their geomorphological features and land cover. At the end of this part the comparison of the extracted model with the reference model DMP 1G using statistical methods is carried out. At the end of this thesis the results are evaluated and discussed. Key words: InSAR, Sentinel-1, SAR, DSM
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Grassland management monitoring based on Sentinel-1 data
Doležal, Jan ; Potůčková, Markéta (advisor) ; Brodský, Lukáš (referee)
The main goal of this diploma thesis was to find and quantify the connection between coherence, entropy, polarimetric angle alpha obtained from Sentinel-1 radar data and grass cutting/pastures. The research was carried out in the area of the Krkonoše national park. To assemble and validate applied methodology, field data was collected 5 times. Hourly rainfall data from Czech hydrometeorological institute was available, but it did not have to be used - no rainfalls were recorded at the time of data acquisitions. Dependence between mowing and the value of coherence has been confirmed. After mowing, median coherence was higher than before mowing. The results were similar to VH as well as VV polarization. Coherence on polygons remained higher after 12-24 days. In total, two different data acquisition geometries (ascending and descending) were examined. The results in both cases were similar. For polarimetric parameters, no correlation between polarimetric parameters and grass mowing or pasture has been confirmed. Keywords: radar, SAR, Sentinel-1, coherence, polarimetry, grass mowing
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Soil moisture estimation using Sentinel-1 radar data
Outrata, David ; Štych, Přemysl (advisor) ; Potůčková, Markéta (referee)
Soil moisture estimation using Sentinel-1 radar data The main aim of this diploma thesis was to find and quantify the relationship between the intensity of backscatter from the Sentinel-1 radar data and the volume soil moisture at the level of agricultural fields. The research was conducted in three areas, in the first part there were two vegetation-free fields near the Thessaloniki (Greece), and information about soil moisture was obtained from own measurements using a thermogravimetric method. The second part drew data from the freely available ISMN database and the research was carried out on agricultural fields during the vegetation season in northwest Germany. The third part used soil moisture data from the Czech Hydrometeorological Institute (ČHMÚ) and the area of interest was two grassed areas of the airport and one agricultural field. Correlation was measured by calculating the determination coefficient and by using the linear regression an equation for calculating the soil moisture from the radar backscatter was compiled. High dependence has been confirmed when VV polarization with constant surface roughness were examined. In the case of surfaces with varying roughness and vegetation cover, only low correlation was found, similarly with using VH polarization. Key words: radar, SAR, Sentinel-1, soil...
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Using Sentinel-1 data for creating a digital terrain model by means of radar interferometry
Karvánek, Matouš ; Potůčková, Markéta (advisor) ; Hlaváčová, Ivana (referee)
Using of Sentinel-1 data for radar interferometry Abstract The diploma thesis deals with extraction of a digital surface model (DSM) using synthetic aperture radar interferometry (InSAR) and Sentinel-1 data in selected locations of the Czech Republic. The InSAR technique, the Sentinel-1 data, their parameters and possibilities of their usage are described in the theoretical part of the thesis. The specification of the model areas and used data follows. The practical part is focused on creating a methodology of deriving a digital surface model and its extracting in the three tested locations. These locations differ from each other in their geomorphological features and land cover. At the end of this part the comparison of the extracted model with the reference model DMP 1G using statistical methods is carried out. At the end of this thesis the results are evaluated and discussed. Key words: InSAR, Sentinel-1, SAR, DSM
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