Search

Transfer functions for reconstruction of the duration of ice-free period at stations in the Chukchi, East Siberian and Laptev seas have been developed by comparison of hydrometeorological data and the chemical composition of bottom sediments accumulated during observation period. It has been established that in addition to the previously discussed processes through which the ice cover affects the chemical composition of bottom sediments (primary bioproductivity and redox conditions of bottom waters), there are several mainly local processes developed on the East Siberian shelf. These are the changes of terrestrial aqueous and solid runoff; coastal abrasion rate; current structure and water exchange through the Bering Strait between the Pacific and Arctic oceans; and intensity and direction of the ice/iceberg rafting of sediments. It is shown that some typical elements (Br, Ca, As, Fe, Ga) can be used as universal geochemical proxies for qualitative reconstruction of ice conditions. [ABSTRACT FROM AUTHOR]

Satellite-derived Antarctic sea ice extent has displayed a slight upward since 1979, but with strong temporal and regional variability—the drivers of which are poorly understood. Here, we conduct numerical experiments with a circum-Antarctic ocean–sea ice–ice shelf model driven by realistic atmospheric surface boundary conditions to examine the factors responsible for the temporal and spatial patterns in observed Antarctic sea ice variability. The model successfully reproduces observed seasonal and interannual variability in total sea ice extent and the temporal/spatial patterns of sea ice concentration and seasonality (days of advance and retreat and actual ice days) for 1979–2014. Sensitivity experiments are performed, in which the interannual variability in wind stress or thermodynamic surface forcing is ignored, to delineate their contributions to Antarctic sea ice fields. The results demonstrate that: (1) thermodynamic forcing plays a key role in driving interannual variability in sea ice extent and seasonality in most Antarctic sectors; (2) only in the Ross Sea the wind stress does become the main driver of sea ice extent variability; (3) thermodynamic forcing largely regulates interannual variability in the timing of sea ice advance, while wind stress largely controls the timing of the sea ice retreat; and (4) although both wind stress and thermodynamic forcing contribute to variability in total sea ice volume, the wind stress plays a dominant role in regulating sea ice volume variability in the near-coastal zone. [ABSTRACT FROM AUTHOR]