The Frequency Response of Glaciers

Abstract

AbstractThe theory developed in previous papers to represent the response of a glacier to changes in the rate of accumulation and ablation has been used for a number of applications. A method of integrating the differential equations for a fixed frequency was programmed for a high-speed digital computer. This provides a better way of finding the frequency response than the earlier method which used series approximations or high and low frequencies. Results are given for (a) an artificial glacier showing varying amounts of diffusion of the kinematic waves, (b) South Cascade Glacier, Washington, U.S.A., as a check on previous results, and (c) Storglaciären, Kebrekaise, Sweden. The response curves of Storglaciären are very similar in shape In those of South Cascade Glacier but, since. Storglaciären moves more slowly, the curves are shifted in frequency (by a factor of two). The phase of the response at the terminus of Storglaciären plotted against frequency shows a double peak.Certain mathematical results for the artificial case of no diffusion are given in an Appendix.A computer programme was also written for calculatingλandμcoefficients and applied to South Cascade Glacier and Storglaciären.