Mass Balance Re-analysis of Findelengletscher, Switzerland; Benefits of Extensive Snow Accumulation Measurements

Frontiers in Digital Humanities

Sold, Leo¹  Hoelzle, Martin¹  Huss, Matthias¹  Salzmann, Nadine¹  Zemp, Michael²  Leysinger Vieli, Gwendolyn²  Linsbauer, Andreas²  Joerg, Philip C.²  Machguth, Horst³ 

[1] Departement of Geosciences, University of Fribourg, Fribourg, Switzerland;Department of Geography, University of Zurich, Zurich, Switzerland;Laboratory of Hydraulics, Hydrology and Glaciology, ETH Zurich, Zurich, Switzerland

关键词: Glacier mass balance;    mass balance modeling;    Snow accumulation;    ground penetrating radar;    European Alps;   

DOI  :  10.3389/feart.2016.00018

学科分类：社会科学、人文和艺术（综合）

来源: Frontiers

【 摘 要 】

A re-analysis is presented here of a 10-year mass balance series at Findelengletscher, a temperate mountain glacier in Switzerland. Calculating glacier-wide mass balance from the set of glaciological point balance observations using conventional approaches, such as the profile or contour method, resulted in significant deviations from the reference value given by the geodetic mass change over a five-year period. This is attributed to the sparsity of observations at high elevations and to the inability of the evaluation schemes to adequately estimate accumulation in unmeasured areas. However, measurements of winter mass balance were available for large parts of the study period from snow probings and density pits. Complementary surveys by helicopter-borne ground-penetrating radar (GPR) were conducted in three consecutive years. The complete set of seasonal observations was assimilated using a distributed mass balance model. This model-based extrapolation revealed a substantial mass loss at Findelengletscher of -0.43m w.e. a^-1 between 2004 and 2014, while the loss was less pronounced for its former tributary, Adlergletscher (-0.30m w.e. a^-1). For both glaciers, the resulting time series were within the uncertainty bounds of the geodetic mass change. We show that the model benefited strongly from the ability to integrate seasonal observations. If no winter mass balance measurements were available and snow cover was represented by a linear precipitation gradient, the geodetic mass balance was not matched. If winter balance measurements by snow probings and snow density pits were taken into account, the model performance was substantially improved but still showed a significant bias relative to the geodetic mass change. Thus the excellent agreement of the model-based extrapolation with the geodetic mass change was owed to an adequate representation of winter accumulation distribution by means of extensive GPR measurements.

【 授权许可】

CC BY