Volume change of McCall Glacier, Arctic Alaska, USA, 1956–2003

Abstract

AbstractA long history of research documents that McCall Glacier, Arctic Alaska, USA, continues to lose mass at a rate that is likely increasing with time. We present a photo comparison (1958-2003) that visually documents these volume changes, along with survey measurements that quantify these losses. Measurements of longitudinal profiles initially acquired from airborne laser altimetry, and repeated by ground-based surveys, indicate that the areally averaged rate of thinning increased between 1956-93 and 1993-2002, from 0.35 ± 0.07 m a-1 to 0.47 ± 0.03 m a-1, respectively; total volume loss was (8.3 × 107) ± (1.7 × 107) m3 and (2.7 × 107) ± (0.2 × 107) m3 (all in water equivalent) for these two time periods. These profiles also indicate that a 1 km stretch of the mid-ablation area is behaving differently from this trend, with a rate of thinning that is not changing with time. Lastly we present a comparison of several methods for calculating volume change and assess their relative errors.