C41B-0695
Greenland ice sheet albedo variability and feedback: 2000-2015
Thursday, 17 December 2015
Poster Hall (Moscone South)
Jason E Box1, Dirk van As1, Robert S Fausto1, Ruth Mottram2, Peter P Langen2 and Konrad Steffen3, (1)Geological Survey of Denmark and Greenland, Copenhagen, Denmark, (2)Danish Meteorological Institute, Copenhagen East, Denmark, (3)WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
Abstract:
Absorbed solar irradiance represents the dominant source of surface melt energy for Greenland ice. Surface melting has increased as part of a positive feedback amplifier due to surface darkening. The 16 most recent summers of observations from the NASA MODIS sensor indicate a darkening exceeding 6% in July when most melting occurs. Without the darkening, the increase in surface melting would be roughly half as large. A minority of the albedo decline signal may be from sensor degradation. So, in this study, MOD10A1 and MCD43 albedo products from MODIS are evaluated for sensor degradation and anisotropic reflectance errors. Errors are minimized through calibration to GC-Net and PROMICE Greenland snow and ice ground control data. The seasonal and spatial variability in Greenland snow and ice albedo over a 16 year period is presented, including quantifying changing absorbed solar irradiance and melt enhancement due to albedo feedback using the DMI HIRHAM5 5 km model.
