Iceberg Detection With RADARSAT-2 Quad-Polarimetric C-Band SAR in Kongsfjorden, Svalbard—Comparison With a Ground-Based Radar

Satellite monitoring of icebergs in the Arctic region is paramount for the safety of shipping and maritime activities. The potential of polarimetric synthetic aperture radar data in enhancing detection capabilities of icebergs under interchangeable and challenging conditions is explored in this work. We introduce RADARSAT-2 quad-pol C -band data to detect icebergs in Kongsfjorden, Svalbard. The location contains two tidewater glaciers and is chosen because multiple processes are present in this region, such as ice formation and its relationship with the glaciers, freshwater discharge. Six state-of-the-art detectors are tested for detection performance. These are the dual-intensity polarization ratio anomaly detector, polarimetric notch filter, polarimetric match filter, symmetry, polarimetric whitening filter (PWF), and optimal polarimetric detector (OPD). In addition, we also tested the parameters of the Cloude–Pottier decomposition. In this study, we make use of a ground-based radar for validation and comparison with satellite images. We show that in calm sea-state conditions, the OPD and PWF detectors give high probability of detection ( PD ) values of 0.7–0.8 when the probability of false alarm ( PF ) value is 0.01–0.05, compared with choppy sea conditions where the same detectors have degraded performance ( PD = 0.5–0.7). Target-to-clutter ratio (TCR) values for each polarization channel is also extracted and compared to the icebergs’ dimensions. The ground-based radar shows higher values in TCR, compared with satellite images. These findings corroborate previous work and show that sea-ice activity, surface roughness, incidence angle, weather, and sea-state conditions all affect the sensitivity of the detectors for this task

SENBYGG

Rapporten dokumenterer resultater fra prosjektet SENBYGG der Statens kartverk er oppdragsgiver. Prosjektet har som formål å detektere bygningsendringer (nybygg, tilbygg eller revet bygg) ved hjelp av radarsatellittene Sentinel-1 A og B. I prosjektet har vi studert flere mulige metoder for endringsdeteksjon. Radarsatellitter (SAR) har relativt god oppløsning (10m) men betydelig med støy. For å redusere støyen midler vi bilder over samme område for hvert kalenderår. Endringer detekteres ved å sammenligne tilbakespredning fra to etterfølgende år. I prosjektet har vi påvist at det er fult mulig å detektere bygningsendringer i SAR bilder basert på årlige middelbilder. Man kan også redusere tidsintervallene noe, men antall feil vil øke siden støyene i bildene da blir mer merkbar.SENBYGGpublishedVersio

InSAR Svalbard – User requirements, technical considerations, and product development plan

The InSAR Svalbard development project (2023–2025) is a partnership between the Geological Survey of Norway (NGU) and NORCE Norwegian Research Centre AS, with funding from the Norwegian Space Agency (Post 74, contract number: 74CO2301). The project aims to start the development of a Ground Motion Service (GMS) in Svalbard, providing spaceborne Synthetic Aperture Radar Interferometry (InSAR) ground displacement maps and time series tailored to Arctic conditions. This report presents the findings from the project's first year, including the outcomes of a user workshop and a user survey conducted in 2023. The study's main goal was to identify the user requirements for an InSAR Svalbard GMS, and to highlight past InSAR research and known for processing limitations. The report also presents a product development plan that considers both user needs and technical considerations.publishedVersio

The glaciers climate change initiative: Methods for creating glacier area, elevation change and velocity products

Glaciers and their changes through time are increasingly obtained from a wide range of satellite sensors. Due to the often remote location of glaciers in inaccessible and high-mountain terrain, satellite observations frequently provide the only available measurements. Furthermore, satellite data provide observations of glacier character- istics that are difficult to monitor using ground-based measurements, thus complementing the latter. In the Glaciers_cci project of the European Space Agency (ESA), three of these characteristics are investigated in detail: glacier area, elevation change and surface velocity. We use (a) data from optical sensors to derive glacier outlines, (b) digital elevation models from at least two points in time, (c) repeat altimetry for determining elevation changes, and (d) data from repeat optical and microwave sensors for calculating surface velocity. For the latter, the two sensor types provide complementary information in terms of spatio-temporal coverage. While (c) and (d) can be generated mostly automatically, (a) and (b) require the intervention of an analyst. Largely based on the results of various round robin experiments (multi-analyst benchmark studies) for each of the products, we suggest and describe the most suitable algorithms for product creation and provide recommendations concerning their practical implementation and the required post-processing. For some of the products (area, velocity) post-processing can influence product quality more than the main-processing algorithm

Rockslide Mapping in Norway by Means of Interferometric SAR Time Series Analysis

Rockslides have a high socioeconomic and environmental importance in many coun- tries. Norway is particularly susceptible to large rockslides due to its many fjords and steep mountains. One of the most dangerous hazards related to rock slope failures are tsunamis that can lead to large loss of life. It is therefore very important to systemati- cally identify potential unstable rock slopes. In this thesis, we consider the use of satellite remote sensing interferometric syn- thetic aperture radar (InSAR) for detecting surface displacement in rural areas of Norway. The main focus of the work has been on developing small baseline (SB) InSAR time series methods for mapping and monitoring of rockslides in Norway. The first part of the thesis is a basic review of the satellite SAR imaging instrument, with a focus on the InSAR methodology. Different satellite sensors and their limitations is discussed. The introduction chapters have been written with the nonspecialist in mind. In the second part of the thesis, we present a discussion about particular InSAR processing challenges in Norway, as well as preliminary results from two ongoing research projects, with the aim of demonstrating the possibilities that emerges by using new high-resolution SAR sensors, as well as the potential to perform continuous surface displacement monitoring using radar corner reflectors. The last chapters of the thesis demonstrate that InSAR is a powerful tool that can be used to identify the relative magnitude and spatial pattern of active rockslide sites on both a regional and individual rockslide site scale

Ground displacements on Aitik tailings dams using SAR Interferometry. (21/2018)

As part of the REmote SEnsing supporting surveillance and operation of Mines (RESEM) project, we performed a preliminary study about the use of Synthetic Aperture Radar Interferometry (InSAR) for documenting ground displacements on tailings dams (Aitik copper mine, Sweden). The Stacking and SBAS methods have been applied to map the spatial distribution of the ground displacements based on 2015–2017 TerraSAR-X and Sentinel-1 satellite data, as well as to retrieve time series between May and November 2017. The 2D InSAR method has been used to combine results from ascending and descending SAR geometries. The report summarized described the main findings of the InSAR analysis and discuss the potential and limitations of the technique for applications in in the mining sector.publishedVersio

Spaceborne radar interferometry (InSAR) for natural hazards, landslides and infrastructure: limitations and potential / Satellittbasert radarinterferometri (InSAR) for naturfare, skred og infrastruktur: begrensninger og muligheter (5/2015)

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Ground displacements on Aitik tailings dams using SAR Interferometry. (21/2018)

As part of the REmote SEnsing supporting surveillance and operation of Mines (RESEM) project, we performed a preliminary study about the use of Synthetic Aperture Radar Interferometry (InSAR) for documenting ground displacements on tailings dams (Aitik copper mine, Sweden). The Stacking and SBAS methods have been applied to map the spatial distribution of the ground displacements based on 2015–2017 TerraSAR-X and Sentinel-1 satellite data, as well as to retrieve time series between May and November 2017. The 2D InSAR method has been used to combine results from ascending and descending SAR geometries. The report summarized described the main findings of the InSAR analysis and discuss the potential and limitations of the technique for applications in in the mining sector

Validation of SAR iceberg detection with ground-based radar and GPS measurements

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