HYDROLOGY OF BRAGANZAVAGEN UNDER ICE-COVERED CONDITIONS

摘要

The hydrology regime of Braganzavagen, the bay in the Van Mijen Fjord, Spitsbergen, has been studied during several winter seasons. Hydrological characteristics of the bay are determined by the local bathymetry, influx from the river Kjellstromelva, semidiurnal tide and land fast ice covering Braganzavagen during 6-7 months of the year. Tidal elevations of the water level in the Van Mijen Fjord are varied from 1 in neap tide to 2 m in spring tide. During the ice season significant part of sea ice in Braganzavagen sits at the bottom continuously, some part of the ice floats in high tide only, and some part of the ice is always afloat. There is no information about river water influx during the ice season. The mining company Store Norske Spitsbergen Kulkompani AS has an interest in the development of coal deposit on the southern shore of Braganzavagen, for which construction of a road crossing from the northern to southern shore of the bay is necessary. Hydrological information is useful for the road design. Visual observation of ice surface, mechanical drilling together with CTD measurements of sea water and temperature and salinity measurements of sea ice along the bay were performed. The river channel was clearly visible due to ice cracks going around the channel. CTD measurement performed in the channel demonstrated significant deformations of tidal curves showing the dependence of the water level from the time with approaching to the river mouth. Variations of the water salinity over the channel were insignificant.