Estimation of Snow Accumulation on Samudra Tapu Glacier, Western Himalaya Using Airborne Ground Penetrating Radar

Abstract

In this study an airborne ground penetrating radar (GPR) is used to estimate spatial distribution of snow accumulation in the Samudra Tapu glacier (the Great Himalayan Range), Western Himalaya, India. An impulse radar system with 350 MHz antenna was mounted on a helicopter for the estimation of snow depth. The dielectric properties of snow were measured at a representative site (Patseo Observatory) using a snow fork to calibrate GPR data. The snow depths estimated from GPR signal were found to be in good agreement with those measured on ground with an absolute error of 0.04 m. The GPR survey was conducted over Samudra Tapu glacier in March 2009 and 2010. A kriging-based geostatistical interpolation method was used to generate a spatial snow accumulation map of the glacier with the GPR-collected data. The average accumulated snow depth and snow water equivalent (SWE) for a part of the glacier were found to be 2.23 m and 0.624 m for 2009 and 2.06 m and 0.496 m for 2010 respectively. Further, the snow accumulation data were analysed with various topographical parameters such as altitude, aspect and slope. The accumulated snow depth showed good correlation with altitude, having correlation coefficient varying between 0.57 and 0.84 for different parts of the glacier. Higher snow accumulation was observed in the north-and east-facing regions, and decrease in snow accumulation was found with an increase in the slope of the glacier. Thus, in this study we generate snow accumulation/SWE information using airborne GPR in the Himalayan terrain.Keywords: Glacier, ground penetrating radar, snow accumulation, snow water equivalent.IN the Himalaya snow and glaciers cover a large geographical area and influence climate and environment of the region. Recent studies carried out using satellite images suggest approximately 40,800 sq. km area is covered by glaciers in the Great Himalaya and Karakoram mountain ranges 1 . These glaciers are a perennial and vital source of freshwater to the countries around the Himalayan chain. In recent years, glaciers and seasonal snow cover in this region have been significantly influenced by climate change 2-7 ; therefore, it is useful to monitor the spatial and temporal changes of snow thickness.Estimation of snow thickness using field-based methods such as snow stakes, automatic sensors, etc. provides mostly point-specific information. However, ground penetrating radar (GPR), a non-destructive technique, can be used to collect both point as well as spatial distribution of snow thickness. It has been widely used in ground mode, for snow and ice thickness measurements [8][9][10][11][12][13][14][15] , snowpack stratigraphic delineation 16 and to study the subsurface properties of other strata 17 . Forte et al. 18,19 reported the applications of GPR data in determining the density and electromagnetic (EM) wave velocity for snow, firn and ice. Colucci et al. 20 used GPR profiles in combination with LiDAR data to calculate the volumetric and mass variations in the body of the ice. Apart from ground...

Reconciling High Glacier Surface Melting in Summer with Air Temperature in the Semi-Arid Zone of Western Himalaya

“…Snow depth measurements between 4700 and 5200 m asl that were conducted in May show that 1.4-1.6 m of snow was accumulated. A recent study by [72] has also observed a similar average accumulated SWE of 0.624 m and 0.496 m during March of 2009 and 2010 over the Samudra Tapu Glacier. Therefore, the ice melt in three seasons suggests the role of snow cover and temperature gradient between the elevations, where the ice surface at lower elevation gets exposed early when compared to that of snow-covered higher elevation.…”

Brief communication: How deep is the snow at the Mount Everest?

“…The transmission velocity is the most critical parameter for estimating snowpack thickness. Because of the limited measurement time window in so-called 'death zone', we did not measure common midpoint data to evaluate the transmission velocity of radar waves inside the snowpack at the Mount Everest t. In general, the transmission velocity in snow ranges from 0.20 m/ns to 0.27 m/ns, which depend on snow properties (Fortin and Fortier, 2001;Singh et al, 2017). A transmission velocity of 0.23 m/ns was obtained in a snowpack according to radar measurements with a steel stake (40 cm in length and 2 cm in diameter) that was buried in snowpack at elevations of 6500 m and 7028 m in 2005 (Sun et al, 2006).…”

Multiparameter Monitoring of Crevasses on an Alpine Glacier to Understand Formation and Evolution of Snow Bridges

“…4A), it is clear that the antennae used for investigating the narrower snow (and crevasses) was less appropriate and only allowed for locating the crevasses along the bedrock profile (Fig. 4B) without allowing a detailed view of their inner structures as was the case with more dedicated GPR studies (e.g., Eder et al, 2008;Singh et al, 2013). Higher frequencies (ideally from a 500-Mhz antenna) should allow for more details in the structure provided.…”