Response of mountain glaciers to climate forcing: Analysis and applications

A variety of analytical techniques is employed in order to probe the relationship between climate and glacier fluctuations. Several glacier parameters are considered, including equilibrium-line altitude (ELA), terminus position, and mass balance. A range of time scales is implicitly considered as well.; Initially, a multiple regression exercise was carried out, using global datasets of both ELA and climate variables. For midlatitudes, variations in elevation of the mean summer freezing isotherm, together with variations in winter precipitation, were found to explain most of the variance in ELA. The derived regression equation was used to partition the observed post-Little-Ice-Age rise of snowlines in the Swiss Alps into components forced by temperature and precipitation changes. It was found that the snowline change is primarily the result of increasing temperature.; In a study of tropical snowline depression at the Last Glacial Maximum (LGM), a single-cell tropical climate model was employed in order to relate changes in boundary conditions at the sea surface to variations in the atmospheric freezing height. It was found that a sea-surface temperature (SST) reduction of 2.8 K in the regions of deep convection is sufficient to produce the observed lowering of snowlines, absent changes in precipitation.; Time series analysis of several century-length records of glacier terminus-position variations in the Swiss Alps yielded no evidence of periodicity, although there does appear to be a lagged negative correlation between fluctuations in regional temperature and those of glacier length. Interannual glacier length changes were found to be partially amenable to representation in the form of low-order autoregressive integrated moving average (ARIMA) models, but only a modest fraction of variance could be explained by such model structures.; Finally, a global dataset of mass balance observations was examined. In the global mean, surface temperature and mass balance were found to be negatively correlated. The results of a simple regression on these data suggested that mass balance, in order to be meaningful, must be referred to some dynamic reference climate, which itself would be expected to have an adjustment time similar to the mean dataset glacier relaxation time. (Abstract shortened by UMI.)...