Is the Longitudinal Profile of Storglaciaren, Northern Sweden, in Balance with the Present Climate?

Abstract

AbstractThe main perturbation in the mass balance of Storglaciären during the twentieth century was caused by a sudden 1°C increase in the summer mean temperature around 1910. Later perturbations of the climate have been of minor importance in relation to the mass balance. Annual field surveys suggest that the mass budget on Storglaciären has been in near balance for the last 15 years. Because of this major step-like change, we can establish the validity of theoretical models giving response times for Storglaciären of the order of 50 years. According to these models, Storglaciären could by now have reached a profile in balance with the present climate. To study this problem, the emergence velocity was calculated and compared with the net balance. The result shows that the emergence velocity either balances or exceeds the net balance for the entire tongue except for the lowermost part, where it decreases to about half of the net balance. A slight further recession of the front position would thus be expected with today’s climate.Calculated balance velocities also suggest that most of the present profile is close to a steady-state profile, if the mean annual sliding velocity is about 50% of the surface velocity. Lower sliding velocities would imply a thickening of the tongue and a thinning of the accumulation area during years of balanced mass budget.