Southern elephant seal movements and Antarctic sea ice

Between December 1996 and February 1997, weaned pups and postmoult female elephant seals (Mirounga leonina) were fitted with satellite transmitters at King George Island (South Shetlands). Of the nine adult females tracked for more than two months, three stayed in a localized area between the South Shetlands and the South Orkneys. The other six females travelled southwest along the coast of the Antarctic Peninsula up to the Bellingshausen Sea. Two of them then moved far northeast and hauled out on South Georgia in October. One female was last located north of the South Shetlands in March 1998. In total, eight females were again sighted on King George Island and six of the transmitters removed. The tracks of the weaners contrasted with those of the adults. In January, five juveniles left King George Island for the Pacific sector ranging about four weeks in the open sea west of the De Gerlache Seamounts. Three of them returned to the tip of the Antarctic Peninsula in June, of which one was last located on the Patagonian Shelf in November 1997. The juveniles avoided sea ice while the adults did not. The latter displayed behavioural differences in using the pack ice habitat during winter. Some females adjusted their movement patterns to the pulsating sea ice fringe in far-distant foraging areas while others ranged in closed pack ice of up to 100 %. The feeding grounds of adult female elephant seals are more closely associated with the pack ice zone than previously assumed. The significance of midwaterfish Pleuragramma antarcticum as a potential food resource is discussed

On the improvement of sea ice models for climate simulations: the Sea Ice Model Intercomparison Project

Experiments with dynamic-thermodynamic sea-ice models indicate a strong dependence of the net freezing rate, sea-ice transport and variability on dynamic model parameters. Although current dynamic-thermodynamic sea-ice models show relatively good agreement with observations, an optimization seems to be necessary, especially for the parameterizations of dynamic processes. Presently, only a few coupled climate models use dynamic-thermodynamic sea-ice models. In order to promote, by means of coordinated numerical experiments, the development of an optimal sea-ice model for climate research, the Sea Ice Ocean Modelling Panel of the Arctic Climate System Study (ACSYS, a project of the World Climate Research Programme) has initiated the Sea Ice Model Intercomparison Project (SIMIP). The first results from this model hierarchy approach are presente

Dynamik des arktischen Meereises - Validierung verschiedener Rheologieansaetze fuer die Anwendung in Klimamodellen

Summary in EnglishAvailable from TIB Hannover: RN 9219(291) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Validating satellite derived and modelled sea-ice drift in the Laptev Sea with in situ measurements from the winter of 2007/2008

A correct representation of the ice movement in an Arctic sea-ice-ocean coupled model is essential for a realistic sea-ice and ocean simulation. The aim of this study is to validate the observational and simulated sea-ice drift for the Laptev Sea Shelf region with in situ measurements from the winter of 2007/08. Several satellite remote-sensing data sets are first compared to mooring measurements and afterwards to the sea-ice drift simulated by the coupled sea-ice-ocean model. The different satellite products have a correlation to the in situ data ranging from 0.56 to 0.86. The correlations of sea-ice direction or individual drift vector components between the in situ data and the observations are high, about 0.8. Similar correlations are achieved by the model simulations. The sea-ice drift speed derived from the model and from some satellite products have only moderate correlations of about 0.6 to the in situ record. The standard errors for the satellite products and model simulations drift components are similar to the errors of the satellite products in the central Arctic and are about 0.03 m/s. The fast-ice parameterization implementation in the model was also successfully tested for its influence on the sea-ice drift. In contrast to the satellite products, the model drift simulations have a full temporal and spatial coverage and results are reliable enough to use as sea-ice drift estimates on the Laptev Sea Shelf