Figure 2: Remotely sensed albedo evaluation for Athabasca Ice AWS.
Figure 3 shows both basins’ mid-summer remotely sensed snow and ice albedo maps. These maps demonstrate the vast spatial variability of intra-HRU and -basin snow and ice albedos. Such spatial variabilities cannot be captured by modelling in scales smaller than its HRU units. Although the intra-HRU albedo variability was averaged out before DA was performed, the collective variations caused by wildfires and heatwaves can generate different integrated responses. This heterogeneity suggests that the remotely sensed albedos can contribute new information to a cold regions DA framework. Intra-basin snow and ice albedo variability is also observed in both basins. For example, in AGRB, there is a clear distinction between lower glacier ice albedos and the higher albedos from the Columbia Icefield. The transition from snow to firn albedos is also evident in PGRB. This date also exhibits an area in which albedo was not retrieved for the most terminal glacier HRU in PGRB. Masked albedo values in Figure 3 can occur if clouds and shadows obstruct the area or if the coarse resolution BRDF retrieval is unable to generate enough observations for a particular landcover class. DA was not performed when there were no snow and ice 20-m albedo pixels inside an HRU, and the modelling continued with its old state variables. Note that there were 68 and 33 dates with available remotely sensed albedo estimates for assimilation in AGRB and PGRB, respectively.