Thermal Regulation of Glacier Surging

摘要: A necessary condition for a glacier to surge by thermal instability is that the be cold with basal ice at or near melting point. Deep temperature measurements show two small surge-type glaciers in Yukon Territory meet this requirement, but shallow three other suggest temperate regime. If latter observations are accepted, not all surges thermally controlled: if single mechanism accounts it cannot instability. In paper argued remains viable explaining of many glaciers, and regardless underlying mechanism, processes must least have major influence on behavior glaciers. Two numerical modelling experiments described. The first involves one-dimensional model which shows control can account remarkably constant cycle found some second, two-dimensional time-dependent structure glacier, relative amounts change considerably as progresses. This variation alone may sufficient explain surges, even case, affect timing compelling feature offers an explanation factors controlling non-random geographical distribution For surface near-temperate bed, thickness, temperature, geothermal flux fortuitously related.