A5086601480- Oceanographic and Atmospheric Processes
- Ocean Waves and Remote Sensing
- Arctic and Antarctic ice dynamics
- Gamma-ray bursts and supernovae
- Methane Hydrates and Related Phenomena
- Geophysics and Gravity Measurements
- Cryospheric studies and observations
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Underwater Acoustics Research
- Electron and X-Ray Spectroscopy Techniques
- Surface and Thin Film Phenomena
- Coastal and Marine Dynamics
- Advanced Computational Techniques and Applications
- Soil Moisture and Remote Sensing
- Marine and coastal ecosystems
- Medical Imaging Techniques and Applications
- Analytical Chemistry and Sensors
- Tropical and Extratropical Cyclones Research
- Copper Interconnects and Reliability
- Climate change and permafrost
- Remote Sensing and Land Use
- SAS software applications and methods
- Paleontology and Stratigraphy of Fossils
- Environmental Monitoring and Data Management
Nansen Environmental and Remote Sensing Center
2008-2020
Norwegian Meteorological Institute
2020
Nansen International Environmental and Remote Sensing Center
2008-2019
University of Copenhagen
2018
University of Oslo
2003-2004
Pennsylvania State University
1993
The synthetic aperture radar (SAR) Doppler centroid has been used to estimate the scatter line-of-sight velocity. In weak moderate ocean surface current environment, SAR is dominated by directionality and strength of wave-induced displacements. this paper, we show how sea state signature can be improve wind retrieval from SAR. shifts C-band return signals are thoroughly investigated colocating measurements ASCAT scatterometer with anomalies retrieved Envisat ASAR. An empirical geophysical...
Abstract. A new Sentinel-1 image-based sea ice classification algorithm using a machine-learning-based model trained in semi-automated manner is proposed to support daily charting. Previous studies mostly rely on manual work selecting training and validation data. We show that the readily available charts from operational services can reduce amount of preparation large amounts training/testing Furthermore, they feed highly reliable data trainer by indirectly exploiting best ability experts...
The processing steps and error corrections needed to retrieve estimates of sea surface range Doppler velocities from Envisat Advanced Synthetic Aperture Radar Wide Swath Medium resolution image products are presented. Retrieval accuracies based on examination the corrected shift measurements assessed. root-mean-square errors after bias found be 4.7 3.9 Hz in VV HH polarizations, respectively. At 35° incidence angle, this corresponds horizontal 23 19 cm/s.
Radarsat-2 C-band quad-polarization SAR observations of crude oil, emulsion, and plant oil slicks acquired in the wind speed range from 4 to 8 m/s incidence angles 30° 50° are analyzed yield new insights into attenuation short waves breaking by surface real conditions. To provide a direct quantitative assessment wave damping, measurements decomposed polarization difference (PD), ratio (PR), nonpolarized (NP), cross-polarized (CP) components. The PD signals relate extent Bragg damping slick...
Abstract Ocean surface radial velocities (RVLs) derived from the Sentinel‐1 A/B Interferomic Wide (IW) mode Doppler frequency shift observations are regularly acquired over Norwegian coastal zone. These data can be used to complement existing ocean observation systems with high‐resolution (up 1.5 × km) spatial current (OSC) maps. In this study, IW Level 2 OSC retrievals were obtained months (October–November 2017) of raw Coastal Current (NCC). The results evaluated using high‐frequency radar...
[1] Sea surface range Doppler velocities from nearly 1200 Envisat Advanced Synthetic Aperture Radar (ASAR) acquisitions between 2007 and 2011, covering the Norwegian Sea, North Skagerrak have been examined. After systematic corrections, inflow of Atlantic Water to via two branches Current, is investigated. Distinct expressions eastern branch, Slope are revealed with a speed 20–40 cm/s clear manifestation topographic steering along 500 m isobath. The western Front also depicted but lower...
We present optical, near-infrared, and X-ray observations of the optical afterglow (OA) rich, long-duration gamma-ray burst GRB 011211. Hubble Space Telescope (HST) data obtained 14, 26, 32, 59 days after burst, show host galaxy to have a morphology that is fairly typical blue galaxies at high redshift. measure its magnitude be . detect break in OA R-band light curve which naturally accounted for by collimated outflow geometry. By fitting broken power-law we find best fit with pre-break...
Long gamma-ray bursts are produced during the dramatic deaths of massive stars with very short lifetimes, meaning that they explode close to birth place their progenitors. During a period become most luminous objects observable in Universe, being perfect beacons study high-redshift star-forming regions. To use afterglow GRB 161023A at redshift $z=2.710$ as background source environment explosion and intervening systems along its line-of-sight. r first time, we complement UV/Optical/NIR...
Nansat is a Python toolbox for analysing and processing 2-dimensional geospatial data, such as satellite imagery, output from numerical models, gridded in-situ data. It created with strong focus on facilitating research, development of algorithms autonomous systems. extends the widely used Geospatial Abstraction Data Library (GDAL) by adding scientific meaning to datasets through metadata, common functionality data analysis handling (e.g., exporting various formats). uses metadata...
Abstract. A new Sentinel-1 image-based sea ice classification algorithm is proposed to support automated charting. Previous studies mostly rely on manual work in selecting training and validation data. We show that the use of readily available charts from an operational services allow automate selection large amount training/testing data void biased, subjective decisions. The scheme has two phases: operational. Both phases start removal thermal, scalloping textural noise calculation gray...
Context. In 2003, the Sun and Earth passed through both equatorial plane of Jupiter therefore orbital planes its main satellites.
Image segmentation remains one of the major challenges in 3D medical image analysis. We describe a generally applicable image-segmentation technique that combines operator interaction and automatic processing, with particular focus on cardiac For given image, method works as follows. First, interactively defines region cues either give 'tissue samples' or impose spatial constraints where regions can cannot lie. Next, three-step relaxation-labeling algorithm is applied. first step, each voxel...