Surface velocity and ice discharge of the ice cap on King George Island, Antarctica

Glaciers on King George Island, Antarctica, have shown retreat and surface lowering in recent decades, concurrent with increasing air temperatures. A large portion of the glacier perimeter is ocean-terminating, suggesting possible large mass losses due to calving and submarine melting. Here we estimate the ice discharge into the ocean for the King George Island ice cap. L-band synthetic aperture radar images covering the time-span January 2008 to January 2011 over King George Island are processed using an intensity-tracking algorithm to obtain surface velocity measurements. Pixel offsets from 40 pairs of radar images are analysed and inverted to estimate a weighted average surface velocity field. Ice thicknesses are derived from simple principles of ice flow mechanics using the computed surface velocity fields and in situ thickness data. The maximum ice surface speeds reach mayor que 225 m/yr, and the total ice discharge for the analysed flux gates of King George Island is estimated to be 0.720+/-0.428 Gt/yr, corresponding to a specific mass loss of 0.64+/-0.38 m w.e./yr over the area of the entire ice cap (1127 km2)

Claiming Space and Struggling for Recognition Partispace Working Paper Two

Aiming at contributing to a better understanding of the current developments, paradoxes and ways to deal with youth political participation in Europe, the main research question of the PARTISPACE project is: How and where do 15- to 30 year-old young people participate differently across social milieus and youth cultural scenes and across eight European cities (framed by different national welfare, education and youth policies)? In relation to this research question, this report was intended to analyse case studies which explore participation practices in formal, non-formal and informal contexts and reconstruct practices, meanings, relationship and dynamics of different forms of youth participation in a comparative perspective and local constellations of youth participation. In so doing, the report has outlined a mosaic of the different practices, activities, styles and spaces wherein young people situate their participation in the eight countries involved in the PARTISPACE project

AUTOMATIC CALCULATION OF OIL SLICK AREA FROM MULTIPLE SAR ACQUISITIONS FOR DEEPWATER HORIZON OIL SPILL

The Deepwater Horizon oil spill occurred in the Gulf of Mexico in April 2010 and became the largest accidental marine oil spill in history. Oil leaked continuously between April 20th and July 15th of 2010, releasing about 780, 000m3 of crude oil into the Gulf of Mexico. The oil spill caused extensive economical and ecological damage to the areas it reached, affecting the marine and wildlife habitats along with fishing and tourism industries. For oil spill mitigation efforts, it is important to determine the areal extent, and most recent position of the contaminated area. Satellitebased oil pollution monitoring systems are being used for monitoring and in hazard response efforts. Due to their high accuracy, frequent acquisitions, large area coverage and day-and-night operation Synthetic Aperture Radar (SAR) satellites are a major contributer of monitoring marine environments for oil spill detection. We developed a new algorithm for determining the extent of the oil spill from multiple SAR images, that are acquired with short temporal intervals using different sensors. Combining the multi-polarization data from Radarsat-2 (C-band), Envisat ASAR (C-band) and Alos-PALSAR (L-band) sensors, we calculate the extent of the oil spill with higher accuracy than what is possible from only one image. Short temporal interval between acquisitions (hours to days) allow us to eliminate artifacts and increase accuracy. Our algorithm works automatically without any human intervention to deliver products in a timely manner in time critical operations. Acquisitions using different SAR sensors are radiometrically calibrated and processed individually to obtain oil spill area extent. Furthermore the algorithm provides probability maps of the areas that are classified as oil slick. This probability information is then combined with other acquisitions to estimate the combined probability map for the spill