The Tidal Effect on Climatic Characteristics of the Kara Sea in the Ice-Free Period

Abstract

Using a high-resolution version of the QUODDY-4 three-dimensional finite-element hydrostatic model, we have carried out two series of numerical experiments. The first estimates tidal changes characterizing the role of tides in the formation of climatic characteristics of the Kara Sea in the ice-free period (the magnitude and directions of velocity of permanent surface currents, temperature, and salinity at the pycnocline base and level of the free sea surface). The second series checks the adequacy of the indirect description of tidal changes in terms of tide-induced baroclinic tidal-energy dissipation and diapycnal diffusion when compared to the explicit method and obtains a quantitative measure that can be used for their comparison. The modeling results indicate, first, that the tidal changes are a significant, if not key, factor; second, that the indirect description of tidal changes is adequate when compared to the explicit method; third, that it is unjustified to disregard these changes (this is common in predicting and computing the climates of marine systems); and, finally, that the correlation averaged over the sea surface area can be taken as a quantitative measure of the similarity of the fields of climatic characteristics obtained for the total (wind + thermohaline + tidal) forcing, on the one hand, and the combined (wind + thermohaline) forcing coupled with the indirect method for the description of tidal changes, on the other.