Oil spill response capabilities and technologies for ice-covered Arctic marine waters: A review of recent developments and established practices

Renewed political and commercial interest in the resources of the Arctic, the reduction in the extent and thickness of sea ice, and the recent failings that led to the Deepwater Horizon oil spill, have prompted industry and its regulatory agencies, governments, local communities and NGOs to look at all aspects of Arctic oil spill countermeasures with fresh eyes. This paper provides an overview of present oil spill response capabilities and technologies for ice-covered waters, as well as under potential future conditions driven by a changing climate. Though not an exhaustive review, we provide the key research results for oil spill response from knowledge accumulated over many decades, including significant review papers that have been prepared as well as results from recent laboratory tests, field programmes and modelling work. The three main areas covered by the review are as follows: oil weathering and modelling; oil detection and monitoring; and oil spill response techniques

Arctic sea ice thickness characteristics in winter 2004 and 2007 from submarine sonar transects

International audienceA transect of the Arctic Ocean by the British submarine Tireless in March 2007 enabled the thickness characteristics of the ice cover to be measured during the winter immediately preceding the exceptional retreat of summer 2007. In this paper we report on mean and modal drafts, probability density functions of draft, and the frequency and depth distribution of pressure ridges, and we compare results with those from an earlier submarine cruise in winter 2004 which covered part of the same area. In the region from north of Fram Strait to Ellesmere Island (about 85 degrees N, 0-70 degrees W) we find no change in mean drafts between 2004 and 2007 though there is a change in ice composition, with more ridging in 2007 but a lesser modal draft. This agrees with the observations of younger ice being driven toward Fram Strait in 2007. The region north of Ellesmere Island continues to be a ``redoubt'' containing more thick deformed multiyear ice than any other part of the transect. In the west the submarine profiled extensively under the SEDNA ice camp at 73 degrees N 145 degrees W. This is in the same location as the 1976 AIDJEX ice camp and a sonar survey done by a U.S. submarine in April 1976. We found that a large decrease in mean draft had occurred (32%) over 31 years and that in 2007 the SEDNA region contained the thinnest ice of any part of the Arctic surveyed by the submarine; this was a region from which the ice completely retreated during the subsequent summer of 2007

Warm water pathways toward Nioghalvfjerdsfjorden Glacier, Northeast Greenland

Nioghalvfjerdsfjorden Glacier (79NG) is the largest of three marine-terminating outlet glaciers draining the Northeast Greenland Ice Stream. To understand how Atlantic waters supply waters in the cavity beneath the floating 79NG, we analyze historic and recent bathymetric, hydrographic, and velocity observations obtained on the Northeast Greenland continental shelf. The bathymetry is characterized by a trough system, consisting of the Westwind Trough and the Norske Trough in the northern and southern part of the continental shelf, respectively. Atlantic waters recirculating in Fram Strait cross the shelf break and enter the trough system at its southeastern inlet toward the inner shelf. Warm Atlantic Intermediate Water (AIW) present below 200 m in the Norske Trough shows large contributions of the recirculating Atlantic water. We found that the bathymetry is sufficiently deep to provide a direct subsurface pathway for warm AIW between the shelf break and the 79NG cavity via the Norske Trough. Likewise, based on the hydrographic data, we show that the Norske Trough supplies AIW warmer than 1°C to the 79NG, which is not present in the Westwind Trough. Our moored and lowered velocity measurements indicate that a boundary current carries warm AIW along the northeastern slope of Norske Trough toward the 79NG. We suggest that anomalies in Atlantic water temperatures in Fram Strait could reach 79NG within less than 1.5 years, thereby modifying the glacier's basal melt rates