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Snowfall is one of the most difficult meteorological variables to measure using automated sensors. These measurements are critically important, as the presence, quantity, and distribution of snow affects regional and global hydrology and climate. Snowfall impacts the albedo of the Earth’s surface, ecosystem function, permafrost characteristics, and the mass balance of glaciers, sea ice, and ice sheets. Snowfall also contributes to weather-related hazards, including avalanches and floods, and creates dangerous conditions for both air and land transport. As Earth’s average atmospheric temperature increases, alpine and northern regions are experiencing remarkable decreases in snowfall and increases in rainfall (Li et al. 2020; Trenberth 2011; Trenberth et al. 2003; IPCC 2019; Mote et al. 2018), and significant reductions in snow cover duration and extent (Derksen and Brown 2012; Derksen et al. 2019). All of these changes are projected to continue in a warming climate. To quantify these trends and better adapt to their effects, the accurate measurement of snow is critical to predict its variations at local, regional, and global scales.
In spite of their importance, snow measurements are still subject to significant uncertainties and biases, particularly in cold and windy conditions (Goodison et al. 1998; Gugerli et al. 2021; Yang et al. 2005; Rasmussen et al. 2012; Buisán et al. 2020; Daly et al. 2017; Langousis et al. 2018; Milewska et al. 2019; Nitu et al. 2018; Pan et al. 2016, 2019; Yao et al. 2018, Zhang et al. 2020). Despite recent advancements in sensor technology, measurement techniques, and communications, snow cover measurements, such as snow depth and snow water equivalent (SWE), are still primarily recorded manually, and require specialized equipment and well-trained personnel. Snow cover on glaciers, ice sheets, sea ice, and land is notoriously heterogeneous, making it difficult to obtain representative measurements over a given area (Picard et al. 2016). Measurement of the liquid water equivalent of precipitation falling as snow, or other forms of solid precipitation, typically requires heated precipitation gauges to prevent full or partial blockage (capping) of the gauge inlet by snow and ice. In addition, precipitation gauges can significantly underestimate the true amount of solid precipitation, primarily due to wind effects. For these reasons, the improvement of snow cover and solid precipitation measurements is an important subject of climatological and...