The use of planimetric surface area in glacier mass-balance calculations: a potential source of errors

Large errors in the estimation of glacier ablation and accumulation may arise from the uncritical use of planimetric surface areas in volume calculations based on specific point values. Three-dimensional digital terrain models of glacier surfaces show that the actual surface area is likely to be substantially larger than the planimetric area. The errors are sufficient for questions to be raised about some calculations of water storage in glaciers, because incorrect surface-area values may result in ablation being underestimated substantially. Errors may also be introduced into calculations of radiation-energy inputs to a crevassed glacier surface. -from Authors