Insolation Topoclimates and Potential Ablation in Alpine Snow Accumulation Basins: Front Range, Colorado

Abstract

Measurements of insolation during the Indian Peaks snowmelt season indicate that the average diurnal trajectory of solar transmission is highly asymmetric with lower values occuring in the afternoon when cloud coverage is maximum. A statistical analysis of simulated insolation suggests that topographic factors interact with prevailing sky conditions to produce a complex pattern of topoclimates within the study area. Differences between insolation topoclimates are not stationary; they depend upon timing and degree of cloud coverage as reflected in the diurnal trends of solar transmission. On an average summer day (clear morning‐cloudy afternoon), simulated insolation to north and south facing basins is roughly equivalent, while east facing basins receive the largest daily totals. These findings are important to snow hydrologists because relative (intramountain) differences in glacier ablation, and therefore potential basin melt, appear to be adjusted to the pattern of radiation that occurs on partly cloudy (not cloudless) days.