Literature discussions

Abstract. This study provides insights into surface mass-balance (SMB) and runoff exiting the Watson River drainage basin, Kangerlussuaq, West Greenland during a 30 year period (1978/1979–2007/2008) when the climate experienced increasing temperatures and precipitation. The 30-year simulations quantify the terrestrial freshwater output from part of the Greenland Ice Sheet (GrIS) and the land between the GrIS and the ocean, in the context of global warming and increasing GrIS surface melt. We used a snow-evolution modeling system (SnowModel) to simulate the winter accumulation and summer ablation processes, including runoff and SMB, of the ice sheet: indicating that the simulated equilibrium line...

Antarctic Bottom Water (AABW) is a key water mass in the Meridional Overturning Circulation, filling much of the abyssal layers of the world ocean. The Weddell Sea is the predominant site for AABW formation, and the source for the AABW that occupies the densest layers of the Atlantic Ocean. Several studies have shown a decadal warming of the AABW layer in the Atlantic, superimposed on significant interannual variability. Recent studies suggest that interannual variability of the AABW in the Scotia Sea may be linked to changes in the baroclinicity of the Weddell Gyre, with the...

While summer Arctic sea-ice extent has decreased over the past three decades, it is subject to large interannual and regional variations. Methodological challenges in measuring ice thickness continue to hamper our understanding of the response of the ice-thickness distribution to recent change, limiting the ability to forecast sea-ice change over the next decade. We present results from a 2400 km long pan-Arctic airborne electromagnetic (EM) ice thickness survey in April 2009, the first-ever large-scale EM thickness dataset obtained by fixed-wing aircraft over key regions of old ice in the Arctic Ocean between Svalbard and Alaska. The data provide detailed insight...

Pelagic seabird populations can use several discrete wintering areas, but it is unknown if individuals use the same wintering area year after year. This would have consequences for their population genetic structure and conservation. We here study the faithfulness of individuals to a moulting area within and among years in a small pelagic seabird, the Thin-billed prion, which moult their primary feathers during the early part of the non-breeding period. According to stable carbon isotope ratios (δ13C) of these feathers, 90% of Thin-billed prions moult in Antarctic and 10% in South American waters. Repeated samples from individuals in 2 or...

Abstract: The services of ecological systems and the natural capital stocks that produce them are critical to the functioning of the Earth's life-support system. They contribute to human welfare, both directly and indirectly, and therefore represent part of the total economic value of the planet. We have estimated the current economic value of 17 ecosystem services for 16 biomes, based on published studies and a few original calculations. For the entire biosphere, the value (most of which is outside the market) is estimated to be in the range of US$16-54 trillion (1012) per year, with an average of US$33 trillion...

Kelp gulls, Larus dominicanus (Aves: Laridae), breeding in Keller Peninsula, King George Island, Antarctic Peninsula Authors: Joaquim O. Branco; Erli S. Costa; Jansen de Araujo; Edison Durigon; Maria Alice S. Alves We examined the distribution, abundance and density of the Kelp Gull, Larus dominicanus (Lichtenstein, 1823), at Keller Peninsula on two occasions during the breeding season of 2007-2008 (once for incubation and once for chick stages) and compared our results with previously published data. We present information on the number of eggs, incubation success, and initial development of L. dominicanus chicks in the studied sites. The abundance and density of the...

The Surface Heat Budget of the Arctic Ocean (SHEBA) experiment produced 18,000 h of turbulence data from the atmospheric surface layer over sea ice while the ice camp drifted for a year in the Beaufort Gyre. Multiple sites instrumented during SHEBA suggest only two aerodynamic seasons over the sea ice. In "winter", the ice was compact and snow covered, and the snow was dry enough to drift and blow. In "summer", the snow melted, and melt ponds and leads appeared and covered as much as 40% of the surface with open water. This paper develops a bulk turbulent flux algorithm...

Likely responses of the Antarctic benthos to climate-related changes in physical disturbance during the 21st century, based primarily on evidence from the West Antarctic Peninsula region. Disturbance has always shaped the evolution and ecology of organisms and nowhere is this more apparent that on the iceberg gouged continental shelves of the Antarctic Peninsula (AP). The vast majority of currently described polar biodiversity occurs on the Southern Ocean shelf but current and projected climate change is rapidly altering disturbance intensities in some regions. The AP is now amongst the fastest warming and changing regions on earth. Seasonal sea ice has decreased in...

Most of the Southern Ocean is a high-nutrient, low-chlorophyll (HNLC) area. Thereare exceptions to this situation downstream of some of the islands, where iron from theislands or surrounding shallow plateau fertilizes the mixed layer and causes aphytoplankton bloom in spring and summer. The main locations where this occurs aredownstream of the South Georgia, Crozet, and Kerguelen islands. Data on mixed layerdepths from Argo float profiles together with Sea-viewing Wide Field-of-view Sensorchlorophyll a (chl a) and photosynthetically available radiation from these high-nutrient,high-chlorophyll (HNHC) areas are combined to study the effects of mixed layer-averagedlight availability on phytoplankton concentrations in areas where iron...

Downwelling radiation in six regional models from the Arctic Regional Climate Model Intercomparison(ARCMIP) project is systematically biased negative in comparison with observations from the Surface HeatBudget of the Arctic Ocean (SHEBA) experiment, although the correlations with observations are relativelygood. In this paper, links between model errors and the representation of clouds in these models areinvestigated. Although some modeled cloud properties, such as the cloud water paths, are reasonable in aclimatological sense, the temporal correlation of model cloud properties with observations is poor. Thevertical distribution of cloud water is distinctly different among the different models; some common featuresalso appear. Most models...