Spatial–Temporal Variability of Great Slave Lake Levels From Satellite Altimetry

The study of lake-level variability of five selected areas across Great Slave Lake (GSL) using satellite altimetry is presented. Data from Topex/Poseidon (TP) and Jason-1 (J1) missions at GSL for the ice-free seasons of 1993-2002 and 2002-2008, respectively, reveal lower performance of J1 for areas closer to 20 km from the coastline compared to 10 km for TP. A calculated bias of 6.99 cm was subtracted to J1 range since TP has better tracking of shoreline waters and lower data rejection. High correlation coefficients for the relative rate of change between lake altimetry heights (LAHs) and corresponding gauge data for Yellowknife Bay and Hay River support the use of LAH changes as effective indicators of variability at GSL. Differences in LAH between the five areas indicate a nonuniform slope which we relate more to variability of the surface water temperature distribution than wind effects. The deeper and colder areas are associated to the least change of LAH gradient through time; therefore, they represent ideal areas to study interannual climate variability. A potential correlation between areas with higher variability in LAH gradients and higher changes in modeled surface water temperatures during the 2003 ice free season is observed.