Now showing items 1-10 of 35
Algal hot spots in a changing Arctic Ocean: Sea-ice ridges and the snow-ice interface
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-12)
During the N-ICE2015 drift expedition north-west of Svalbard, we observed the establishment and development of algal communities in first-year ice (FYI) ridges and at the snow-ice interface. Despite some indications of being hot spots for biological activity, ridges are under-studied largely because they are complex structures that are difficult to sample. Snow infiltration communities can grow at ...
Agreement and Complementarity of Sea Ice Drift Products
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-08)
Changes in Arctic sea ice have raised questions about changes in sea ice drift patterns. Reduced sea ice coverage may open up the Arctic to further exploration of maritime activities, particularly during the summer months. Given such changes, it is important to investigate differences between available sea ice drift products. Products based on synthetic aperture radar (SAR), radar scatterometer, and ...
Assessment of RISAT-1 and Radarsat-2 for Sea Ice Observation from Hybrid-Polarity Perspective
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-25)
Utilizing several Synthetic Aperture Radar (SAR) missions will provide a data set with higher temporal resolution. It is of great importance to understand the difference between various available sensors and polarization modes and to consider how to homogenize the data sets for a following combined analysis. In this study, a uniform and consistent analysis across different SAR missions is carried ...
Can we extend local sea-ice measurements to satellite scale? An example from the N-ICE2015 expedition
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-17)
Knowledge of Arctic sea-ice conditions is of great interest for Arctic residents, as well as for commercial usage, and to study the effects of climate change. Information gained from analysis of satellite data contributes to this understanding. In the course of using in situ data in combination with remotely sensed data, the question of how representative local scale measurements are of a wider ...
X-, C-, and L-band SAR signatures of newly formed sea ice in Arctic leads during winter and spring
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-02)
We examine an extensive synthetic aperture radar (SAR) data set from the Arctic Ocean spanning a time period from January to June 2015, with the aim of identifying multi-polarization parameters that can be used to accurately separate newly formed sea ice from the surroundings. Newly formed sea ice areas both provide favourable routing for ship traffic, and are key to Arctic climate science because ...
Hon förebygger miljökatastrofer
(Others; Andre, 2015)
Det får inte hända. men om det ändå gör det behövs ny teknik för att mildra effekterna. Malin Johanssons forskning handlar om att förebygga miljökatastrofer, när oljebolagen söker sig allt längre in i Arktis.
Synthetic Aperture Radar Remote Sensing of Operational Platform Produced Water Releases
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-03)
Oil spill detection services based on satellite synthetic aperture radar (SAR) frequently detect oil slicks close to platforms due to legal releases of produced water. Separating these slicks from larger releases, e.g., due to accidental leakage is challenging. The aim of this work is to investigate the SAR characteristics of produced water, including the typical appearance in HH/VV data, possible ...
Malin letar oljespill i ishavet
(Chronicle; Kronikk, 2020-03-13)
Can Mineral Oil Slicks Be Distinguished From Newly Formed Sea Ice Using Synthetic Aperture Radar?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-18)
In this feasibility study discriminating oil slicks and newly formed sea ice using SAR imagery is investigated, using imagery from the L-band high-resolution Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) airborne and the satellite C-band RADARSAT-2 (RS-2) systems. To determine the separability of these two varying but similar appearing low backscatter ocean surfaces, multi-polarization ...
Consistent ice and open water classification combining historical synthetic aperture radar satellite images from ERS-1/2, Envisat ASAR, RADARSAT-2 and Sentinel-1A/B
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-17)
Synthetic Aperture Radar (SAR) satellite images are used to monitor Arctic sea ice, with systematic data records dating back to 1991. We propose a semi-supervised classification method that separates open water from sea ice and can utilise ERS-1/2, Envisat ASAR, RADARSAT-2 and Sentinel-1 SAR images. The classification combines automatic segmentation with a manual segment selection stage. The ...