This paper gives the results of investigations carried out in the Fugleberget basin which lies on the northern shore of the Hornsund Fiord, in the unglaciated region of raised sea terraces and on the slopes of the Fugleberget (569 m a.s.l.) and the Ariekammen (511 m a.s.l.). The investigations were carried out between 23 July, 1979 and 4 September, 1980, including the polar night. The Fugleberget basin represents well the area of sea terraces and coastal mountains uncovered with glacier and occupying large areas in West Spitsbergen. These areas are characterized by the presence of permafrost. The aim of investigations was to determine such fluvial processes as the duration of the hydrological period, the manner of water supply to the basin and an attempt to define the elements of the water balance. In addition studies were made on hydrological processes, particulary changes in the chemical composition of water, and the magnitude of denudation determined.

The Hornsund region is characterised by a topoclimatic variation, which results principally from the local orography, the vicinity of open sea and the two contrasting environments: non-glaciated and glaciated. The specific types of atmospheric circulation determine the local thermal differences. The west coast is characterised by the most favourable thermal conditions, where air temperature is largely determined by foehn processes. The temperature at the Baranowski Station is 0.8°C higher on average than that of the Polish Polar Station on the northern shore of Hornsund . The temperature in the northern shore of the fjord happens to be higher than that on the west coast, which is attributed to the NW cyclonic inflow of cool Arctic air masses. During intermediate weather, when ground frost-thaw takes place, the northern shore of Hornsund is warmer by 0.5°C ; whereas, during moderately frosty weather, it is warmer by 0.2°C than the west coast. The differences result from the effect of the warmer fjord waters on the surrounding air temperature. During moderately warm weather, more favourable conditions occur near the Baranowski Station, expressed by the mean temperature difference of 0.9°C. The greatest temperature difference of 1.5°C on average is normally recorded during warm weather.

This paper contains thsults of hydrological and hydrochemical investigations carried out in the basin of Werenskiöld Glacier against the background of determining climate elements. It also gives chosen elements of the water balance and mass balance determined from year-long investigations of the polar hydrological year 1979-1980.