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Retrieving Soil Moisture States Using Streamflow Data Assimilation. C. Rüdiger a , J.P. Walker a , J.D. Kalma b , G.R. Willgoose c , and P.R. Houser d a Dept. of Civil & Env. Eng., University of Melbourne, Australia b School of Engineering, University of Newcastle, Australia
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Retrieving Soil Moisture States Using Streamflow Data Assimilation C. Rüdigera, J.P. Walkera, J.D. Kalmab, G.R. Willgoosec, and P.R. Houserd aDept. of Civil & Env. Eng., University of Melbourne, Australia bSchool of Engineering, University of Newcastle, Australia cSchool of Geography, University of Leeds, United Kingdom dHydrological Sciences Branch, NASA GSFC, USA
Koster et al., JHM, 2000 Christoph Rüdiger AGU May 2004
Christoph Rüdiger AGU May 2004
Goulburn Catchment Newcastle Sydney Melbourne 0km 1000km Christoph Rüdiger AGU May 2004
Goulburn Catchment Streamgauge Climate Soil Moisture www.civenv.unimelb.edu.au/~jwalker/data/oznet/ Christoph Rüdiger AGU May 2004
Catchment Land Surface Model • Prognostic variables: • Catchment Deficit • Surface Moisture Excess • Root Zone Excess Depth Moisture Deficit Water Table Eq. profile Saturation Koster et al., JGR, 2000 Christoph Rüdiger AGU May 2004
Internal routing Velocity weight v-1 Travel time Tpi Christoph Rüdiger AGU May 2004
Synthetic ExperimentVariational Data Assimilation • “Truth”: • 10yr spin up • 1yr full run • “Experiment 1”: • One month only • Degraded soil moisture values (low catchment deficit) • “Experiment 2”: • “Openloop 1” and changed forcing (33% lower radiation and 20% higher precipitation) • NLFIT (Kuczera, WRR, 1982) model output time Christoph Rüdiger AGU May 2004
Results “Experiment 1” Discharge Soil Moisture Christoph Rüdiger AGU May 2004
Results “Experiment 1” Christoph Rüdiger AGU May 2004
Results “Experiment 2” Discharge Soil Moisture Christoph Rüdiger AGU May 2004
Conclusion from Results • Results show that runoff has information about soil moisture states • Problems in semi-arid regions, when overestimation of water input due to degraded forcing data • Monthly assimilation windows have positive impact, reduction of assimilation window should improve results further Christoph Rüdiger AGU May 2004
Acknowledgments • Australian Research Council (ARC-DP grant 0209724) • Hydrological Sciences Branch, National Aeronautics and Space Administration (NASA), USA • University of Melbourne • Melbourne International Fee Remission Scholarship (MIFRS) • Postgraduate Overseas Research Experience Scholarship (PORES) Christoph Rüdiger AGU May 2004