Temperature Distribution and Thermal Anomalies Along a Flowline of the Greenland Ice Sheet

Download or read book Temperature Distribution and Thermal Anomalies Along a Flowline of the Greenland Ice Sheet written by Joel A. Harrington and published by . This book was released on 2016 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Englacial and basal temperature data for the Greenland Ice Sheet (GrIS) are sparse and mostly limited to deep interior sites and ice streams, providing an incomplete representation of the thermal state of ice within the ablation zone. Here we present 11 temperature profiles at 5 sites along a 34-km E-W transect of western Greenland. These profiles depict ice temperatures along a flowline and local temperature variations between closely-spaced boreholes. A temperate basal layer is present in all profiles, increasing in thickness in the flow direction, where it expands from ~3% of ice height furthest inland to 100% at the margin. Temperate thickness growth is inconsistent with modeled heat contributions from strain heating, heat conduction, and vertical extension of the temperate layer. We suggest that basal crevassing, facilitated by water pressures at or near ice overburden pressure, is responsible for the large temperate ice thicknesses observed. Warm temperature kinks at 51-85 m depth are likely remnants from the thermal influence of partially water-filled crevasses up ice sheet. These profiles demonstrate the ability of meltwater to rapidly alter ice temperatures at all depths within the ablation zone.