Sensitivity of the Mackenzie River Basin Hydrology to Solar Radiation Uncertainties

• Main Authors: N. Voisin, H. G. Leighton, E. D. Soulis, J. Feng
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: WATCLASS; MAGS; solar radiation; hydrology sensitivity; Mackenzie River; Mackenzie Basin; Mackenzie river
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.569.1641; http://www.easternsnow.org/proceedings/2002/013_Voisin.pdf

One of the goals of the Mackenzie GEWEX Study (MAGS) is to model the critical components of the water and energy cycles that affect the climate of the Mackenzie Basin. The hydrological model WATCLASS is used to simulate the energy and water transports at and below the surface. Atmospheric input to WATCLASS is provided by the output from the atmospheric model GEM. There may be significant uncertainties in the GEM incoming solar radiation due largely to difficulties in simulating cloud radiative properties. The question that we address is how these uncertainties affect the energy and water budgets of this northern river watershed. To assess this sensitivity, two WATCLASS model runs are compared. Both runs are driven by atmospheric data from GEM for the 1998-99 water year but in the second run shortwave radiation fluxes retrieved from satellite measurements replace the GEM fluxes. Preliminary results show that the atmospheric model overestimates the incoming solar radiation field by 36%. This results in an increase in the basin annual average surface temperature of 1oC and overestimates in net longwave radiation, and sensible and latent heat fluxes. Snowmelt starts earlier with a decreased first snowmelt peak in runoff hydrograph.