Tromsø, Norway
Tromsø, Norway

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Rott H.,University of Innsbruck | Yueh S.H.,Jet Propulsion Laboratory | Cline D.W.,National Oceanic and Atmospheric Administration | Duguay C.,University of Waterloo | And 11 more authors.
Proceedings of the IEEE | Year: 2010

Snow is a critical component of the global water cycle and climate system, and a major source of water supply in many parts of the world. There is a lack of spatially distributed information on the accumulation of snow on land surfaces, glaciers, lake ice, and sea ice. Satellite missions for systematic and global snow observations will be essential to improve the representation of the cryosphere in climate models and to advance the knowledge and prediction of the water cycle variability and changes that depend on snow and ice resources. This paper describes the scientific drivers and technical approach of the proposed Cold Regions Hydrology High-Resolution Observatory (CoReH2O) satellite mission for snow and cold land processes. The sensor is a synthetic aperture radar operating at 17.2 and 9.6 GHz, VV and VH polarizations. The dual-frequency and dual-polarization design enables the decomposition of the scattering signal for retrieving snow mass and other physical properties of snow and ice. © 2006 IEEE.


Hawley R.L.,Dartmouth College | Brandt O.,Norwegian Polar Institute | Dunse T.,University of Oslo | Hagen J.O.,University of Oslo | And 5 more authors.
Journal of Glaciology | Year: 2013

Winter balance is an important metric for assessing the change on glaciers and ice caps, yet measuring it using ground-based techniques can be challenging. We use the European Space Agency prototype Airborne SAR/Interferometric Radar Altimeter System (ASIRAS) to extract snow depths from the received altimeter waveforms over Austfonna ice cap, Svalbard. Additionally, we attempt to distinguish the long-term firn area from other glacier facies. We validate our results using snow depth and glacier facies characterizations determined from ground-based radar profiles, snow pits and a multilook satellite synthetic aperture radar image. We show that the depth of the winter snowpack can be extracted from the altimeter data over most of the accumulation zone, comprising wet snow zone and a superimposed ice zone. The method struggles at lower elevations where internal reflections within the winter snowpack are strong and the winter snow depth is less than-1m. We use the abruptness of the eflection from the last summer surface (LSS) to attempt to distinguish glacier facies. While there is a general correlation between LSS abruptness and glacier facies, we do not find a relationship that warrants a distinct classification based on ASIRAS waveforms alone.


Rott H.,University of Innsbruck | Cline D.W.,National Oceanic and Atmospheric Administration | Duguay C.,University of Waterloo | Essery R.,University of Edinburgh | And 7 more authors.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2012

(CoReH2O) satellite mission was selected for detailed scientific and technical studies within the Earth Explorer Programme of ESA. The sensor is a dual frequency SAR, operating at 17.2 GHz and 9.6 GHz, VV and VH polarizations The mission will deliver spatially distributed snow and ice observations to improve the representation of the croysphere in hydrological and climate models. Primary parameters are the extent and water equivalent (SWE) of the snow pack and snow accumulation on glaciers. Scientific preparations of the mission include the development and testing of algorithms for retrieval of snow parameters, studies on synergy of CoReH2O-type snow products with passive microwave measurements, the assimilation of satellite snow data in process models, and field experiments. Performance of retrievals for snow extent and SWE was tested with simulated and experimental data, including Ku- and X-band SAR images of the airborne SnowSAR system. © 2012 IEEE.


Rott H.,University of Innsbruck | Cline D.W.,National Oceanic and Atmospheric Administration | Duguay C.,University of Waterloo | Essery R.,University of Edinburgh | And 8 more authors.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2011

The COld REgions Hydrology High-resolution Observatory (CoReH20) satellite mission has been selected for detailed scientific and technical studies within the ESA Living Planet Programme. The mission addresses the need for distributed snow and ice observations to improve the representation of the cryosphere in climate models and the prediction of the water cycle. The sensor is a dual frequency SAR, operating at 17.2 GHz and 9.6 GHz, VV and VH polarizations. This configuration enables the decomposition of the scattering signal for retrieving snow mass (SWE) and other physical properties of snow and ice. A major task for mission preparation is the development and testing of algorithms for SWE retrieval. The baseline algorithm applies a constrained minimization approach, matching forward computed and measured backscatter by iterating for SWE and effective grain size of the snow volume. Experimental campaigns on Ku- and X-band backscatter of snow deliver important information for retrieval development and validation. © 2011 IEEE.


Anensen N.,University of Bergen | Hjelle S.M.,University of Bergen | Van Belle W.,Norut IT | Haaland I.,University of Bergen | And 8 more authors.
Oncogene | Year: 2012

The wild-type tumor-suppressor gene TP53 encodes several isoforms of the p53 protein. However, while the role of p53 in controlling normal cell cycle progression and tumor suppression is well established, the clinical significance of p53 isoform expression is unknown. A novel bioinformatic analysis of p53 isoform expression in 68 patients with acute myeloid leukemia revealed distinct p53 protein biosignatures correlating with clinical outcome. Furthermore, we show that mutated FLT3, a prognostic marker for short survival in AML, is associated with expression of full-length p53. In contrast, mutated NPM1, a prognostic marker for long-term survival, correlated with p53 isoforms Β and γ expression. In conclusion, p53 biosignatures contain useful information for cancer evaluation and prognostication. © 2012 Macmillan Publishers Limited All rights reserved.

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