Continuous Snow Water Equivalent Monitoring on Glaciers using Cosmic Ray Neutron Sensor Technology: A Case Study on Hintereisferner, Austria

Snow water equivalent (SWE) is crucial for assessing snow mass in various fields, particularly on glaciers to quantify accumulation and ablation of the winter snow cover. Presently, the majority of glacier science relies on manual measurements once or a few times per year, given the limited techniques for continuous SWE monitoring and the challenging conditions in a high mountain environment. The Cosmic Ray Neutron Sensor (CRNS) offers sub-daily SWE estimates derived from neutron counts. Though CRNS’s potential was first identified in the 1980s, its deployment on glaciers remains scarcely studied. This study employs a CRNS installed on Hintereisferner (HEF), Austria. Comparing CRNS outputs with frequent manual SWE measurements, the results demonstrate a MAE of 34 kg m−2 (14 %). Applying an independent automated snow depth measurement, a snow density deviation of 34 kg m−3 (9 %) is identified. The CRNS appears remarkably resilient in harsh conditions, providing nearly continuous 1 hour data over the last 3 years. The study evaluated the performance of three snow models - SNOWPACK, ∆snow, and ∆snow 2.0 - in estimating SWE against CRNS measurements. While SNOWPACK, with its physically-based approach, delivered the best results, ∆snow stood out for its simplicity, requiring only snow depth measurements. ∆snow 2.0, with slight adaptations in its maximum density module, showed significant improvement and performed almost as well as SNOWPACK in terms of MAE.

Recommended citation: Schroeder M., Prinz, R., Binder, M., Winkler, M., Schellander, H. (2024). "Continuous Snow Water Equivalent Monitoring on Glaciers using Cosmic Ray Neutron Sensor Technology: A Case Study on Hintereisferner, Austria." Proceedings, International Snow Science Workshop, Tromso, Norway, 2024.
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