Fine-Scale Spatial Variability in Seasonal Snowpack Trends
Abstract
Detailed investigations of recent trends in seasonal snow across mountainous regions generally report snowpack declines at observation stations. However, previous research has also highlighted that these snow monitoring stations are not always representative of snow in surrounding areas. Small changes in snowpack storage in headwater areas could have important implications for downstream areas. Therefore, the objective of this study was to evaluate the fine-scale spatial variability of trends in simulated snowpack properties across the Rio Grande Headwaters of Colorado using a spatially distributed snow evolution modeling system. SnowModel simulations were run at a grid resolution of 100 m and 3-hourly timestep over a 34-year period (1984-2017) accounting for temporal changes in forest canopy from bark-beetle and wildfire disturbances. Annual summary values of simulated snowpack properties were used to compute trends for each model grid across the domain. The trend results were then summarized based on topographic and land-cover characteristics to evaluate the variability of simulated changes in seasonal snow across the study area. Increasing trends in mean winter air temperature of approximately 0.3°C per decade were consistent across the study area, while decreasing trends in winter precipitation (P) ranged from -35 to -76 mm per decade with the greatest magnitude decreases occurring at the highest elevations. Decreasing trends in simulated peak snow water equivalent (SWE) were comparable to trends in winter P, but the greatest percentage of area with statistically significant trends occurred in the middle elevations. Statistically significant decreasing trends in snowmelt rate were predominantly found in the middle elevations with decreases on the order of -2.4 mm/day per decade, whereas decreasing trends in snowmelt timing (ranging from -5 to -9 days per decade) were of the greatest magnitude at the lowest elevations. This study also highlights how the spatial variability of simulated trends in snowpack properties across the study area was correlated with land-cover type and disturbance. Our results generally agree with the widespread snow declines that have been reported in this region but provide further insight into how different snowpack properties may be changing across the basin scale.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C33C1581S
- Keywords:
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- 0736 Snow;
- CRYOSPHERE;
- 0740 Snowmelt;
- CRYOSPHERE;
- 0758 Remote sensing;
- CRYOSPHERE;
- 1863 Snow and ice;
- HYDROLOGY