A Snow Density Dataset for Improving Surface Boundary Conditions in Greenland Ice Sheet Firn Modeling

Frontiers in Digital Humanities

van As, Dirk¹  Braithwaite, Roger J.²  Colgan, William²  Koenig, Lora S.³  McGrath, Daniel⁴  Vandecrux, Baptiste⁵  Box, Jason E.⁵  Charalampidis, Charalampos⁵  Fausto, Robert S.⁵  Steffen, Konrad⁵  Machguth, Horst⁶  MacFerrin, Michael J.⁷ 

[1] Arctic Technology Centre, Technical University of Denmark, Denmark;Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, United States;Department of Geography, University of Zurich, Switzerland;Department of Geosciences, University of Fribourg, Switzerland;Geological Survey of Denmark and Greenland, Denmark;Swiss Federal Institute of Technology, Switzerland;Swiss Federal Research Institute WSL, Switzerland

关键词: Greenland ice sheet;    firn;    Surface mass balance;    densification;    surface snow density;    mass balance modeling;    model boundary conditions;   

DOI  :  10.3389/feart.2018.00051

学科分类：社会科学、人文和艺术（综合）

来源: Frontiers

【 摘 要 】

The surface snow density (SSD) of glaciers and ice sheets is of fundamental importance in converting volume to mass in both altimetry and surface mass balance studies, yet it is often poorly constrained. Site-specific SSDs are typically derived from empirical relations based on temperature and wind speed. These parameterizations commonly calculate the average density of the top meter of snow, thereby systematically overestimating snow density at the actual surface. Therefore, constraining SSD to the top 0.1 m can improve boundary conditions in high-resolution firn-evolution modeling. We have compiled an extensive dataset of 200 SSD point measurements from firn cores and snow pits on the Greenland ice sheet. We find that SSD within 0.1 m of the surface has an average value of 315 kg m-3 with a standard deviation of 44 kg m-3, and has an insignificant annual air temperature dependency. We demonstrate that two widely-used SSD parameterizations dependent on temperature systematically overestimate SSD over the Greenland ice sheet by 17-19%, and that using a constant density of 315 kg m-3 may give superior results when applied in surface mass budget modeling.

【 授权许可】

CC BY