Dependence of the energy balance of the Greenland ice sheet on climate change: Influence of katabatic wind and tundra

• Published in: Quarterly Journal of the Royal Meteorological Society
• Main Author: Meesters, Antoon
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1994
• Subjects: Greenland; glacier; Ice Sheet; Tundra
• Online Access: http://dx.doi.org/10.1002/qj.49712051702; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fqj.49712051702; https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.49712051702

Abstract The summer‐time atmospheric circulation at the margin of a large ice sheet, with an extended adjacent tundra, is investigated with a two‐dimensional atmospheric model. The assumed topography corresponds to the section through west Greenland for which the Greenland Ice Margin Experiment (GIMEX) was performed. With this model, the local sensitivity of the ablation of the ice sheet to changes in the external parameters (which pertain to climate) is explored. The main focus is the sensitivity which is related to atmospheric dynamics. A comparison is made between the results with an exposed tundra and results with a snow‐covered tundra. In the latter case, the katabatic wind is strongly reduced close to the ice margin, so that the downward sensible‐heat flux for the ablation zone is more than halved. This shows that the influence of the exposed tundra on the energy balance of the ice sheet is important. Increasing the initial air temperatures leads to a stronger katabatic wind. As a consequence, the downward sensible‐heat flux at the ablation zone is strongly enhanced. Neglecting the change of the katabatic wind would lead to a much smaller growth of this flux, which shows that the presence of an exposed tundra increases the sensitivity of the energy balance of the ice sheet to climate change. For those runs the large‐scale wind is zero, but in the presence of an inland‐directed large‐scale wind a strong surface wind parallel to the glacier front is found to develop above the ablation zone, by which the sensible‐heat flux is increased. The advection of heated air from the tundra to the ice sheet plays a lesser role.