A decade long analysis of snow dynamics in the Lake Superior Basin using the Snow Data Assimilation System.

Abstract:

We used the Snow Data Assimilation System (SNODAS) derived snow water equivalent (SWE) dataset to characterize timing, duration, and magnitude of the spring freshet for various US Lake Superior watersheds during the past decade. The SNODAS product provides daily estimates of SWE at 1 km resolution from 30 Sept 2003 to present. By monitoring the change in water contained in the snowpack for a given watershed over time, it is possible to quantify the timing, duration, and magnitude of the spring freshet in a given watershed for multiple years. Variability in the onset of the spring freshet in the past is evident in the Lake Superior basin, providing strong indication of variability in export of allocthonous DOC to Lake Superior. Specifically, metrics such as center of mass of spring runoff, timing of melt initiation, timing of snow absence and duration of snowmelt for the study watersheds were determined using the SNODAS SWE dataset. Large variation in timing, duration and magnitude of snowmelt is evident for all watersheds over the past decade. Additionally, spatial variation in snowmelt timing is apparent.