Author(s): V. V. Ivanov; Yu P. Doronin; V. A. Tsarev
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Keywords: No Keywords
Abstract: The mathematical model consists of linearized equations of water motion, continuity, hydrostatistics, heat conduction and diffusion of salt, of ice growth, melting and drift. The temperature of freezing was determined as a function of salinity. Numerical modelling allowed us on the basis of known meteorological and boundary hydrological characteristics to simulate 3-dimensional fields of water salinity and temperature and the inflow of sea water to the estuary, which is strongly influenced by the river runoff. The time period when the temperature of the estuary surface decreased to that of freezing was taken to be the date of freezing. The modelling showed the drifting ice to rapidly become continuous and immobile (fast ice). In winter due to the decreasing river runoff sea water penetrates far to the estuary, the halocline shifts more to the surface, the heat flux to the bottom of ice is practically absent and the ice thickness increases more rapidly. The bottom ice melting began after water temperature increase up to the temperature of ice melting due to the thermal runoff. The surface melting started after the transition of heat exchange with the atmosphere to positive values. Modelling for several years in advance allowed us to simulate full annual cycle of hydrological processes and fields of the nontidal estuary: fields of temperature, salinity, currents, ice cover. They turned out to be to a great extent interrelated. The modelling allowed us to estimate the extent of this interconnection. The comparison of the calculated results with the observational data of several estuaries showed quite a good agreement between them.
Year: 1990