Tidal Changes in a Regional Marine System Climate: Two Means of Their Allowing for, as Applied to the Barents Sea in Summer

Kagan B. A., Sofina E. V.

Direct and indirect means of allowing for tidal effects in models of a regional marine system climate are discussed. The first of them is based on inserting a tidal constituent into external forcing. Whereas the second one is based on parameterizing internal tidal wave-induced dissipation of baroclinic tidal energy in terms of diapycnal diffusion. The results of two numerical experiments carried out in the frame of the three-dimensional finite-element hydrostatic model QUODDY-4, which includes or ignores tidal effects, are presented. A purpose of these numerical experiments is to determine how much important these effects are and where precisely they show up most clearly. A comparison of parameters (modulus and direction) of surface permanent currents, seawater temperature and salinity at the depth of pycnocline and mean dynamic topography of the free surface in the marine system considered, predicted in the above cases, is given. It is found that the tidal changes in the climatic characteristics are manifested most clearly in the Pechora Sea and the polar frontal zone. Overall the inclusion of tides does not favour any radical reorganization of the marine system climate, but its local changes can be pronounced. Also, we provide a comparison between differences of the above enumerated climatic characteristics obtained when the tidal effects are described directly and indirectly. It testified that the indirect means is acceptable.

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