(Nunatsiaq News, 6 September 2012) -- Following the new record low Arctic sea ice extent recorded Aug. 26, ice coverage has continued to drop and has now shrunk to less than four million square kilometres — smaller than the previous low extent of 2007. Compared to September conditions in the 1980s and 1990s, the Arctic sea ice extent has dropped by 45 per cent, the Colorado-based National Snow and Ice Data Center said Sept. 5. And that skimpy sea ice cover is likely to get lower yet, because at least one more week remains in the melt season.
Posted 6 September 2012; 3:41:45 PM. Permalink
(Center for Coastal and Ocean Mapping Joint Hydrographic Center, 6 September 2012) -- A blog detailing the daily progress of the Healy as researchers study the Arctic Ocean and map the sea floor. Blog post from September 5, 2012: Today we returned to the seafloor knoll that was partially sounded on August 31 to fully map the feature and determine if it rises above the 2500 m depth contour. (The 2500-m contour is a key element in establishing limits of the extended continental shelf.) Our multibeam mapping determined that the highest point of the knoll is about 2690 m deep and thus does not give us a 2500-m contour to work with. Nonetheless, we now have a detailed survey of the knoll to replace the vague shape on the existing maps. After we acquire the multibeam echo sounder data, our data processing watch team “processes” the data. In data processing, we confirm that the ship’s position and attitude data are valid and we clean erroneous depth values from the sounding data. These erroneous depth values can arise from interference from other echo sounders, bubbles or ice under the ship, mechanical noise from the ship’s machinery, or often just from weak echoes returning from the seafloor. The cleaned depth values are combined into a digital depth data grid for display and analysis.
Posted 6 September 2012; 3:31:17 PM. Permalink