Looking out for the ice you can’t see: a simple method for estimating regional glacier melt reduction under supraglacial rock debris

October 9, 2012 • Filed under: News — melanie.rohr

Sam Herreid will introduce a new method for measuring glacier melt under debris cover in this week’s WERC seminar, Friday, October 12.

Friday Seminar Series

  • What: Looking out for the ice you can’t see: a simple method for estimating regional glacier melt reduction under supraglacial rock debris
  • Who: Sam Herreid
  • When: 3:30-4:30 p.m. Friday, Oct. 12
  • Where: 531 Duckering

Two research scientists in snow-covered mountain setting surrounded by camping gear and instruments looking out over rock debris

A skeptic looks on while Sam proves it possible to drill into glacier ice below a thick layer of supraglacial debris.
The drill bit was destroyed moments later. Photo by Andy Bliss

Every mountain glacier system on Earth is covered to some extent by a layer of supraglacial rock debris. The thickness and thermal properties of the rock layer play an important role in governing the glacier surface energy balance and therefore glacier melt. Due to the heterogeneous nature of debris cover and the difficulties of in situ data collection, accounting for melt under debris cover is a challenging problem that is frequently oversimplified or overlooked in glacier melt models. One relatively easy measurement that can be made remotely is surface temperature of debris-covered ice. A relationship between surface temperature and supraglacial debris thickness has been developed extensively in glaciology literature; however, a satellite-based, regional-scale estimate of reduced ablation from debris cover is still lacking. We selected the Delta Mountains, a sub-range of the
Alaska Range, to test a new method that uses ASTER thermal data, a 5-meter resolution DEM and sparse field observations to estimate regional glacier melt reduction under debris cover.