Ocean Warming of Nares Strait Bottom Waters Off Northwest Greenland, 2003–2009

• Main Authors: Andreas Münchow, Kelly K. Falkner, Humfrey Melling, Berit Rabe, Helen L. Johnson
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Oceanography Society 2011
• Subjects: Arctic Ocean; International Polar Year; IPY; Petermann glacier; Nares Strait; Oceanography; GC1-1581; Arctic; Baffin Bay; Greenland; Nares; Amundsen Basin; amundsen basin; Baffin; glacier; Nares strait
• Online Access: https://doaj.org/article/111fa88f507f4598b3f36e70643b9948

Over the last 60 years, the perception of the Arctic Ocean has changed from a hostile, sluggish, steady, ice-covered environment with little global impact to an ocean that has become increasingly accessible, apparently rapidly changing, only partly ice-covered, and connected to the global meridional overturning circulation. Our new observations demonstrate that waters off Northwest Greenland constitute the final limb in the grand cyclonic circulation of the Atlantic layer in the Arctic Ocean. These waters with an Atlantic water mass signature are warming in Nares Strait to the west of Greenland as they are elsewhere. Estimates of the magnitude and uncertainty of this warming are emerging from both moored observations and historical hydrographic station data.Ocean temperatures sensed by instruments moored 3 m above the bottom between 228 and 366 m depth in Nares Strait suggest a mean warming of about 0.023 ± 0.015°C per year for the 2003–2009 period at 95% confidence. Salinity changes for the same period are not significantly different from zero. Nevertheless, oscillating bottom temperatures covary with salinities. Mean bottom salinities in Nares Strait exceed 34.56 psu while no water with salinities above 34.51 psu occurs in Baffin Bay to the south. These data indicate a dominantly northern source for the waters sensed by our moorings. Mean bottom temperatures hover near 0°C, which suggests minimal influence of waters from the northeastern Amundsen Basin in the Arctic Ocean. Thus, we conclude that the observed warming originates from the northeastern Canadian Basin to the southwest of our study area.In addition to these mean conditions, we find large interannual variability. For example, significant freshening emerges for the 2003–2006 period that reaches –0.02 ± 0.008 psu per year without significant concurrent temperature trends at three sensor locations. These data contrast with the 2007–2009 observational period when five different sensors all indicate warmer waters (0.063 ± 0.017°C per year) and saltier ...