Zagadnienie odtworzenia wartości bilansu Lodowca Hansa (SW Spitsbergen)

This article deals with an attempt to estimate the value of the net balance of Hansbreen (SW Spitsbergen).In order to estimate thes value an assumption has been made that the value of the net balance of Hansbreen is a function of two groups of factors, i.e. static and dynamic ones. The static elements (georgaphical location of Hansbreen, topography of the glacier and its surroundings, etc.) have no influence on the elements of the interannual changeability of the balance; a constant value will represent these elements in formulae. A group of dynamic factors that introduces an interannual changeability to the net balance is made up of a set of meteorological factors (mainly the course of air temperature, precipitation and cloudiness). The said meteorological factors are influenced by the character of atmospheric circulation. Because the main features of the character of the interannual changeability of the air circulation over that area are influenced by the spatial distribution of the anomalies sea surface temperature (SST), the analysis of variances has been chosen as the method used to define the direct statistical estimation of winter and summer balances as the function of monthly anomalies in SST occurring in the North Atlantic in a preceding period. As a result of statistical analysis, two linear functions of great statistical significance have been obtained, i.e. formula [1] and [2] enabling the estimation of winter and summer balances respectively. These functions use the values of anomalies in SST as independent variables. The influence of these values on the course of changeability in atmospheric circulation over the Nordic seas is obvious. The calculated values of the net balance of Hansbreen, estimated by means of the above mentioned functions and the values observed (Fig. 4) proved to be almost the same. Having the values of anomalies in SST (Reynolds data set) a sequence of values of net balance of Hansbreen has been estimated for the period 1970/71÷1996/97 (Table 2, Fig. 5) with the help of this method. An error of values calculated in this way can be found within limits ą0.106 m. water equivalent. The values of the calculated net balance taken from the above mentioned period were used to find by means of best estimating correlation between Hansbreen net balance and temperature and precipitation sums at Isfjord Radio station. Thanks to these results, the next sequence of values of Hansbreen balance for period 1926/27÷1969/70 (Table 3, Fig. 6) has been calculated. The final values are of no statistical significance and contain unknown errors. If they are close to reality it might mean that the balance of Hansbreen has been permanently negative since the end of the 20-ties.