Now you see it, now you don't: a case study of ephemeral snowpacks and soil moisture response in the Great Basin, USA

摘要

Ephemeral snowpacks, or those that persist for 25 days in the lowest ( 2500 m) elevations. During this time period snowpack was highly variable. The maximum seasonal snow cover during water years 2005–2014 was 64?% in 2010 and at a minimum of 24?% in 2014. We found that elevation had a strong control on snow ephemerality, and nearly all snowpacks over 2500?m were seasonal except those on south-facing slopes. Additionally, we used SNODAS-derived estimates of solid and liquid precipitation, melt, sublimation, and blowing snow sublimation to define snow ephemerality mechanisms. In warm years, the Great Basin shifts to ephemerally dominant as the rain–snow transition increases in elevation. Given that snow ephemerality is expected to increase as a consequence of climate change, physics-based modeling is needed that can account for the complex energetics of shallow snowpacks in complex terrain. These modeling efforts will need to be supported by field observations of mass and energy and linked to finer remote sensing snow products in order to track ephemeral snow dynamics.