The MAGS integrated modeling system

Abstract

The Mackenzie GEWEX Study (MAGS) integrated modeling system was developed to couple, with full feedback, selected atmospheric and hydrologic models, with the expectation that the imposed consistency will enhance the performance of both models and so mitigate the lack of data for northern basins. As each modeling community moved towards using a common land surface scheme based on the Canadian land surface scheme CLASS, a new mesoscale distributed hydrologic model (WATCLASS) was created, using CLASS for vertical processes and the routing algorithms from WATFLOOD. The version of CLASS used in the atmospheric models was modified to reflect the experience with WATCLASS. Changes were made primarily to the soil water budget and included improvements in the between-layer transfer procedures, the addition of lateral flow, and the enhancement of the treatment of cold soil. The drainage database for the Mackenzie River Basin (MRB) was built from GTOPO-30 digital elevation model and the CCRS-II AVHRR-based landcover classification. Streamflow simulations using the WATCLASS model are compared to measured values for both the MAGS research basins and the major tributaries of the Mackenzie. As well as streamflow, simulated internal state variables from WATCLASS are compared to detailed measurements taken in the research basins. Finally, the water balance of the MRB is examined and the change in storage within the basin is compared to satellite data. © 2008 Springer-Verlag Berlin Heidelberg.