Fjernmålingsbasert kartlegging og overvåking av tidevannssonen

Source at https://www.miljodirektoratet.no/publikasjoner/2021/mai-2021/satellite-based-national-intertidal-zone-mapping-of-continental-norway-with-sentinel-12/The report describes updated methods that were originally developed in Haarpaintner & Davids (2020) to map the intertidal zone, in terms of atmospheric exposure, type and areal extent, based on radar and optical high resolution (10m) satellite imagery from Sentinel-1A/B (C-band synthetic aperture radar, C-SAR) and Sentinel-2A/B (multi-spectral instruments) of the European Copernicus Program. It further presents the application of the method to create products covering the whole Norwegian coast, and describes some limitations and error sources. The project resulted in a first version of national products of the intertidal zone area, type and its atmospheric exposure

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

Sluttrapport: Fjernmålingsbasert kartlegging og overvåking av tidevannssonen.

The report describes developed methods and results based on radar and optical high resolution (10-20m) satellite imagery from Sentinel-1 C-band synthetic aperture radars (C-SAR) S1A and S1B and Sentinel-2 MultiSpectral Instruments (MSI) S2A and S2B from the European Copernicus Program to map the intertidal zone in Trondheimsfjorden, Norway, with the aim to extend it nationally.Miljødirektorate

ESA DUE Innovator III SAR for REDD – D2.3 Final Report. (5/2018)

publishedVersio

The Storfjorden polynya: ERS-2 SAR observations and overview

Persistent polynyas have been observed over several winters in Storfjorden, situated between Spitsbergen and Barentsøya/Edgeøya in the south of the Svalbard archipelago. Polynyas are in general active regions with respect to ocean-atmosphere heat exchange, presenting strong convection phenomena and as such being involved in important water mass formation and having an impact on the marine ecosystem. Hydrographic observations have revealed very dense (cold and saline) brine-enriched bottom waters leaving the continental shelf as gravity driven plumes into the deep sea west of Spitsbergen. Satellite observations, using ERS-2 SAR imagery, reveal the evolution of the Storfjorden polynya during winter 1997/98. After forming a complete ice cover until mid-January, Storfjorden responds dynamically to northerly winds by opening a large latent heat polynya. It occupies at its largest extent a region of up to 6000 km2 of open water, thin ice and brash ice. Comparable in size to other large Arctic polynyas, the Storfjorden polynya might have the same or even greater importance in the thermohaline circulation and bottom water mass formation. Ice production is estimated at 30 km3 in Storfjorden, rejecting around 700 Mt (Megatons) of salt that can raise the salinity in Storfjorden by 0.9-1.0 PSU. First studies and the winter 1997/98 evolution of this polynya are presented in this paper

Numerical modelling of the Storfjorden (Svalbard) polynya development due to wind stress : role of the sea ice rheology and damping forces

Remote sensing of the ice cover in Storfjorden (Svalbard) revealed the persistence and evolution of latent heat polynyas during the winter of 1997/98. Latent heat polynyas open mechanically under wind stress or ocean currents that transport the ice cover away. In the present work we used mathematical modelling to simulate the Storfjorden polynya size and geometry caused by wind stress, measured at the meteorological station on the island of Hopen in winter 1997/98. The dependence of the polynya outlines on the wind velocity is presented. Two approaches were used: quasi-static and dynamic. Quasi-static simulations are based on a time-independent, linear ice stress-strain relationship valid for the low strain rates only. Time dependence of the ice cover fracture is joined with stress-strain nonlinearity caused by ice delayed-elastic recovery and viscosity. Results are compared to satellite observations from the synthetic aperture radar (SAR) of ERS-2. The simulation results show that a northern wind opens a larger polynya (ca. 30%) than does a north-eastern wind with the same speed. The results also indicate that the bathymetry and geometry of the fjord might have a stronger influence on the polynya opening and development than the location of individual islands and reefs

Formation de saumures par production de glaces de mer dans Storfjorden, Svalbard, estimée à partir d'images ers-2 sar et de simples modèles de dérive et formation de glaces de mer

VERSAILLES-BU Sciences et IUT (786462101) / SudocSudocFranceF

Mapping Atmospheric Exposure of the Intertidal Zone with Sentinel-1 CSAR in Northern Norway

The intertidal zone (ITZ) is a highly dynamic and diverse coastal ecosystem under pressure that provides important eco-services. Being periodically under water makes it challenging to monitor, and the only possibility to map it in all tidal stages is by using dense time series of observations. At high latitudes, the Sentinel-1 (S1) constellation of the European Copernicus Program consistently provides radar imagery at fixed times on a near-daily basis, independently of cloud cover and sunlight. As tides have a period of 12 h 25.2 min, 1–2 year long S1 time series are therefore able to sample the whole tidal range and, thus, map the percentage of atmospheric exposure of the ITZ, which is an important environmental parameter. Tidal reference levels of mean high/low water at spring, mean and neap tide correspond each to specific percentiles of tidal heights and inversely correspond to atmospheric exposure. The presented method maps atmospheric exposure on the basis of purely statistical analyses of Sentinel-1 time series without the need for any tidal gauge data, by extracting water lines via simple thresholding of radar backscatter percentiles images. The individual thresholds for the second, fifth, 25th, 50th, 75th, 95th, and 98th percentile image were determined by fitting the threshold contour lines to in situ water line GPS tracks collected at corresponding tidal reference levels at five locations around Tromsø in Northern Norway. They inversely correspond to atmospheric exposures of 98%, 95%, 75%, 50%, 25%, 5%, and 2%, respectively. The method was applied to the whole Tromsø Municipality resulting in an ITZ atmospheric exposure map. The validation shows that the mean low water lines at neap, mid, and spring tide were mapped with accuracies of 93%, 84%, and 64%, respectively. The overall approach should be applicable worldwide