WP 2.3: Interaction of atmospheric, cryospheric and hydrological processes at glacier surfaces

Workpackage leader: Carl Egede Bøggild, CRCG/UNIS

SVALI PhD students: Sergey Matjenko, Björn Claremar

Objectives

• To improve the present knowledge of the way melt water is either retained or discharged through cold firn in present and future climate.
  
• To derive algorithms of bare glacier ice albedo in order to predict the ice albedo field in future climate.
  
• To analyze and parameterize atmospheric boundary-layer and surface processes for better characterization in cryospheric models. 

Background

Present day modelling of the future response of ice sheets and glaciers are based on an operational parameterization of relatively complex processes. The current day parameterizations are calibrated for present day conditions, but they probably break down or lose validity in different climate settings. One example is the effect of water retention on the mass balance of the Greenland Ice Sheet in future warmer climate. The percolation zone of the ice sheet will grow at the expense of the dry-snow zone, but the growth of firn aquifers, water routing and freeze-on into superimposed ice will probably not have the same characteristics as the percolation zone has today at much lower elevations. Other examples are the change of surface albedo where warming causes exposure of large areas of glacier ice. This ice at higher elevation, in turn, shows indications of being significantly darker than present day glacier ice at lower elevation and a feedback loop of darkening, melting and thinning of glaciers and ice
sheets may result. Changes in wind strengths and in wind directions in future climate may also have a profound impact on the surface mass balance of many glaciers.