New Mexico Geological Society Annual Spring Meeting — Abstracts

Water stored as seasonal snow is a fundamental resource for the Western Unites States. Snowpack feeds a substantial part of the streamflow over the region, contributes to groundwater recharge, and modulates the temperature regimes of land surface and subsurface. For this reason, accurately predicting changes in snowpack over the region is of great importance for designing resilient water management strategies. Despite their importance, snow processes are still challenging to represent in hydrological models and in climate models. One of the main challenges for predicting the evolution of seasonal snowpack is quantifying the effects of light-absorbing-particles such as black carbon and dust. Once deposited on snow, these particles lead to a decreased snow albedo, that is, to a darkening of the snow surface. This darkening in turn accelerates snow aging (another albedo-decreasing process) and thus leads to a positive feedback, increasing the energy absorbed by the snowpack and snow melt rates. How much these processes accelerate spring snow melt over the Western United States is still poorly understood. Here we try to answer this question by using a recently developed snow model (GLASS, or “Global Land Snow Scheme”), which explicitly models the deposition of black carbon and dust, as well as the evolution of snow grains with aging. By running the model with and without the deposition of light-absorbing particles, we quantify the overall effect on snow melt at sites where in-situ observations are available for model validation. We find that at multiple sites in the mountains of southern Colorado the deposition of mineral dust can accelerate the melt-out date by about 25 days compared to the case of “clean” snow. We further discuss the implications of this finding for water management in the Southwestern US, as effects of this magnitude are expected to significantly impact both the timing and magnitude of streamflow over the region.

References:

1. Zorzetto, Enrico, Paul Ginoux, Sergey Malyshev, and Elena Shevliakova. "Quantifying radiative effects of light-absorbing particle deposition on snow at the SnowMIP sites." The Cryosphere 19, no. 3 (2025): 1313-1334.
2. Zorzetto, Enrico, Sergey Malyshev, Paul Ginoux, and Elena Shevliakova. "A global–land snow scheme (GLASS) v1. 0 for the GFDL Earth System Model: formulation and evaluation at instrumented sites." Geoscientific Model Development 17, no. 19 (2024): 7219-7244.