Automated ablation stakes to constrain temperature-index melt models

Abstract

We developed automated ablation stakes to measure colocated in situ changes in relative glacier-surface elevation and climatological drivers of ablation. The designs, refined over 10 years of development and deployments, implement open-source hardware and common building materials. The ablation stakes record distance to the snow/ice surface, air temperature and relative humidity every 1–15 min. Using these high-frequency data, we demonstrate that melt factors calculated using standard melt-rate vs temperature regressions converge over averaging windows of approximately 12 h or greater. Furthermore, we evaluate an integral approach to estimating temperature-index melt factors for ablation. In a test case on Glaciar Perito Moreno, Argentina, this integral approach reveals an overall positive-degree-day melt factor of 7.5 mm w.e. $^\circ$C−1 d−1. We describe four deployments with iteratively improved designs and provide a list of materials required to construct an automated ablation stake.

Keywords

• glacier mass balance
• glacier monitoring
• glaciological instruments and methods
• glacier ablation phenomena
• melt–surface