This thesis focuses on ablation research carried out on the Rakhiot Glacier (Punjab Himalaya), the Dome Glacier (Canadian Rocky Mountains), and the Debris Glacier (Saint Elias Mountains). Specifically, detailed measurements of debris cover characteristics, ablation rates and meteorological conditions allow specification of relationships between debris cover and ablation. In addition to direct measurements, ablation rates were monitored through the employment of a bulk aerodynamic energy balance model to allow analysis of the dependence of ablation on all external parameters within the atmospheric boundary layer, as well as all internal parameters within the debris cover. Results from each of the three sites were then compared in order to obtain some idea of global variability of the above mentioned processes in high alpine glaciated environments. Lastly, a comparison between the hydrological regimes of two adjacent glaciers, the Athabasca and Dome, was made in order to determine the effects of a debris cover on meltwater discharge characteristics.

Direct ablation measurements at all sites support previous research, indicating a sharp increase in ablation as debris cover thickness increases from 0.0 to 1.0 cm, followed by a decrease in ablation as debris cover thickness increases beyond 1.0 cm. Field observations revealed that, beyond a critical thickness of 3.0 cm, ablation is suppressed from that expected on debris-free ice. Surface energy balance investigations at each site indicated that the enhanced ablation, where the debris cover is thinner than the critical thickness, is primarily due to increased solar radiation absorption. Suppressed ablation, in areas where the debris cover is thicker than the critical thickness, is primarily due to energy absorption (storage) within the debris cover. Comparative analysis between the three sites indicates that the debris cover/ablation relationship follows the same trends but to differing degrees.