HR: 1340h
AN: H23D-1161    [Abstracts]
TI: GRACE Measurements of the Mackenzie River Basin Water Balance
AU: * Snelgrove, K R
EM: snelgrov@cc.umanitoba.ca
AF: University of Manitoba Department of Civil Engineering, 15 Gillson Street, Winnipeg, MB R3T 5V6 Canada
AU: Yirdaw-Zeleke, S
EM: umyirdaw@cc.umanitoba.ca
AF: University of Manitoba Department of Civil Engineering, 15 Gillson Street, Winnipeg, MB R3T 5V6 Canada
AU: Soulis, E D
EM: rsoulis@uwaterloo.ca
AF: University of Waterloo Department of Civil Engineering, 200 University Avenue, Waterloo, ON N2L 3G1 Canada
AB: Direct measurement of an integrated watershed storage amount may be considered a panacea for the ills of watershed modeling. Watershed models typically transfer moisture and energy between model "stores" using physically based transfer laws and conservation equations to produce streamflow hydrographs. Because of the problem of non-uniqueness in the generation of model hydrographs, it has become increasingly important to ensure the representativeness of model results. This is being accomplished by: a) performing model integrations over long, multi-year periods, b) applying models to watersheds with diverse hydroclimatic conditions, c) comparing model "stores" with measured components of watershed storage such as snow depth, soil moisture, groundwater levels, and lake storage. Many of these components, however, either are not regularly measured or have large uncertainties associated with their values. Lack of a true integrated storage measurement represents an unwanted degree of freedom in watershed modeling. In 2002, the GRACE (Gravity Recovery And Climate Experiment Mission) satellite platform was launched to measure, among other things, the gravitational field of the earth. Over its five year life a pair of orbiting satellites will produce a time series of "mass" changes of the earth-atmosphere system. When integrated over a number of years, this will yield a highly refined picture of the earth's gravity. However, month to month changes in mass is an indicator of the integrated value of watershed moisture storage. It has been reported by Wahr et al. (2004) that when smoothed over 1000 km that centimeter accuracy can be achieved in monthly storage change. The goal of this research to compare changes in moisture storage over the Mackenzie River basin using GRACE data with those developed by atmospheric and hydrologic water balances developed under the Mackenzie GEWEX Project (MAGS). Monthly estimates of watershed storage have been developed for the basin through the analysis of streamflow hydrographs using the WATFLOOD and WATCLASS hydrologic models and these have been validated independently through atmospheric water balance computations (Strong et al., 2002 Atmosphere-Ocean).
DE: 1836 Hydrologic budget (1655)
DE: 1863 Snow and ice (1827)
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting