Abstract
Efficient collection of snow depth and density data is important in field surveys used to estimate the winter surface mass balance of glaciers. Simultaneously extensive, high resolution and accurate snow-depth measurements can be difficult to obtain, so optimization of measurement configuration and spacing is valuable in any survey design. Using in-situ data from the ablation areas of three glaciers in the St. Elias Mountains of Yukon, Canada, we consider six possible survey designs for snow-depth sampling and $N$=6--200+ sampling locations per glacier. For each design and number of sampling locations, we use a linear regression on topographic parameters to estimate winter balance at unsampled locations and compare these estimates with known values. Average errors decrease sharply with increasing sample size up to $N\approx$10--15, but reliable error reduction for any given sampling scheme requires significantly higher $N$. Lower errors are often, but not always, associated with sampling schemes that employ quasi-regular spacing. With both real- and synthetic data, the common centreline survey produces the poorest results overall. The optimal design often requires sampling near the glacier margin, even at low $N$. The unconventional ``hourglass'' design performed best of all designs tested when evaluated against known values of winter balance.
Highlights
Distributed glacier-wide estimates of seasonal snow accumulation are critical for understanding glacier mass balance and for predicting the availability and timing of surface runoff, especially in mountainous regions (e.g., Kaser et al, 2010; Huss and Hock, 2018)
Point-scale values of winter balance are obtained from direct measurements of snow depth and density (Figure 1)
For each survey design we investigate the effect of sample size N, where N ranges from a minimum of six to a maximum determined by the number of gridcells sampled (57 to 228 depending on the survey design)
Summary
Distributed glacier-wide estimates of seasonal snow accumulation are critical for understanding glacier mass balance and for predicting the availability and timing of surface runoff, especially in mountainous regions (e.g., Kaser et al, 2010; Huss and Hock, 2018). The net accumulation of snow on a glacier over a winter season is known as the winter surface mass balance, or “winter balance” and is typically reported in metres of water equivalent (m w.e.) (e.g., Østrem and Brugman, 1991; Cogley et al, 2011). Winter balance accounts for half of the seasonally resolved mass balance, initialises ablation conditions and affects energy and mass exchange between the land and atmosphere (e.g., Hock, 2005; Réveillet et al, 2016).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
