Hydrology Seminar – Wednesday October 3rd, 11:30am

Dr Keith Musselman, Postdoctoral Research Associate at the Centre for Hydrology, will present a seminar entitled
Inter-annual snow accumulation and melt patterns in forested and alpine terrain;
a case study from the Sierra Nevada, California

On Wednesday October 3rd, 2012, at 11:30am, in AGRI 1E85
Results are presented from a study of snowpack dynamics in the southern Sierra Nevada, California. The study area covers 1800 km2 and a 3600 m elevation gradient. The accuracy of a distributed snow model is evaluated against a multi-scale suite of field measurements including a network of snow depth sensors, basin-scale manual surveys, and airborne LiDAR. In general, the model accurately simulated the seasonal maximum snow depth and SWE at lower and middle elevations. The model overestimated SWE at upper elevations where wind effects are pronounced and no precipitation measurements were available. The SWE errors were partially explained (R2 > 0.80, p<0.01) by the distance of the SWE measurement from the nearest precipitation gauge. The results suggest that precipitation uncertainty and wind redistribution are both critical limitations on snow model accuracy, particularly at upper elevations. Analyses of snowmelt patterns highlight distinct differences in melt dynamics at lower, middle, and upper elevations. Specifically, forested middle elevations experienced the most sustained snowmelt at relatively low seasonal average melt rates (~ 5 mm day-1). This unique melt timing and rate may be critical to the local forest ecosystem. Furthermore, the three years evaluated in this study indicate a marked sensitivity of this elevation range to seasonal meteorology, suggesting that it could be highly sensitive to future changes in climate.