Melt layer stratigraphic evidence of increasing summer snow melt on Mt. Hunter, Alaska over the last 400 years

Tuesday, 16 December 2014
Dominic Winski1, Erich C Osterberg1, Karl J Kreutz2, Mark Baum1 and Cameron P Wake3, (1)Dartmouth College, Hanover, NH, United States, (2)Univ Maine, Orono, ME, United States, (3)University of New Hampshire Main Campus, Durham, NH, United States
The Arctic has experienced dramatic warming trends during the instrumental period. Alaska, in particular has undergone temperature increases of 1-2 °C since 1950, when widespread meteorological records have been available. Melt layers in ice cores provide a means of extending temperature records far into the past. We present an ice core melt layer record extracted from the Central Alaska Range from a plateau location on Mt. Hunter (63° N, 151° W, 4,000 meters above sea level). The melt layer record provides an estimate of the summer temperature history of this site over the last 400 years. Our results show an increase in summer melting on Mt. Hunter during the period of record. Very infrequent melting occurred on Mt. Hunter prior to the year 1850 (roughly 1 event/century). Between 1850 and 1950 melting became more prevalent with roughly one melt event/decade. Since 1950, melt frequency and percentage as been increasing, in agreement with the instrumental records at lower elevation.