Inhaltszusammenfassung

Arctic flaw polynyas are considered to be highly productive areas for the formation of sea ice throughout the winter season. Most estimates of sea-ice production are based on the surface energy balance equation and use global reanalyses as atmospheric forcing, which are too coarse to take into account the impact of polynyas on the atmosphere. Additional errors in the estimates of polynya ice production may result from the methods of calculating atmospheric energy fluxes and the assumption of ...Arctic flaw polynyas are considered to be highly productive areas for the formation of sea ice throughout the winter season. Most estimates of sea-ice production are based on the surface energy balance equation and use global reanalyses as atmospheric forcing, which are too coarse to take into account the impact of polynyas on the atmosphere. Additional errors in the estimates of polynya ice production may result from the methods of calculating atmospheric energy fluxes and the assumption of a thin-ice distribution within polynyas. The present study uses simulations of the mesoscale weather prediction model COSMO, where polynya area is prescribed from satellite data. The polynya area is either assumed to be ice-free or to be covered with thin ice of 10 cm. Simulations have been performed for two winter periods (2007/08 and 2008/09). When using a realistic thin-ice thickness of 10 cm, sea-ice production in Laptev polynyas amount to 30 km³ and 73 km³ for the winters 2007/08 and 2008/09, respectively. For open water polynyas, higher turbulent energy fluxes are present, which results in a 50-70% increase in sea-ice production (49 km³ in 2007/08 and 123 km³ in 2008/09). Most previous studies seem to have overestimated the ice production in the Laptev Sea.» weiterlesen» einklappen

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Klassifikation

DFG Fachgebiet:
Atmosphären-, Meeres- und Klimaforschung

DDC Sachgruppe:
Naturwissenschaften