Brief communication: Application of a muonic cosmic ray snow gauge to monitor the snow water equivalent on alpine glaciers

Rebecca Gugerli,Nadine Salzmann,Darin Desilets

doi:10.5194/tc-16-799-2022

Abstract

Abstract. Monitoring the snow water equivalent (SWE) in the harsh environments of high mountain regions is a challenge. Here, we explore the use of muon counts to infer SWE. We deployed a muonic cosmic ray snow gauge (μ-CRSG) on a Swiss glacier during the snow-rich winter season 2020/21 (almost 2000 mm w.e.). The μ-CRSG measurements agree well with measurements by a neutronic cosmic ray snow gauge (n-CRSG), and they lie within the uncertainty of manual observations. We conclude that the μ-CRSG is a highly promising method to monitor SWE in remote high mountain environments with several advantages over the n-CRSG.

Highlights

The snow water equivalent (SWE) of the seasonal snowpack is a key variable of the hydrological and climate system and highly relevant for hydrological, glaciological and meteorological studies, especially in high mountain regions
The aim of this study is to explore the use of muons to infer temporally continuous SWE in a high-mountain glacierized site and to provide a first-cut calibration function for the μ-CRSG
In June, snow ablation dominates and the difference between the sub-μ-CRSG and top μ-CRSG decreases until they have similar count rates in August 2021, when the site becomes snow free

Summary

Introduction

The snow water equivalent (SWE) of the seasonal snowpack is a key variable of the hydrological and climate system and highly relevant for hydrological, glaciological and meteorological studies, especially in high mountain regions. Several investigated methods take advantage of naturally occurring cosmic radiation to infer SWE temporally continuously These methods make use of gamma radiation (e.g., Osterhuber et al, 1998; Choquette et al, 2008) or of neutrons from secondary cascades of cosmic rays (Kodama et al, 1975). The neutronic cosmic ray snow gauge (n-CRSG), a method proposed by Kodama et al (1975), measures the attenuation of incoming secondary neutrons on the ground below the snowpack to infer SWE. This has proved successful (e.g., Wada et al, 1977; Kodama et al, 1979; Kodama, 1980; Avdyushin et al, 1982), especially for remote and harsh environments (e.g., Howat et al, 2018; Gugerli et al, 2019). Some drawbacks such as the limited measurement precision that can be achieved with a reasonably sized sensor have been identified (e.g., Gugerli et al, 2019)

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