1. Retrieving Soil Moisture States Using Streamflow Data Assimilation
C. Rüdigera, J.P. Walkera, J.D. Kalmab,
G.R. Willgoosec, and P.R. Houserd
a Dept. of Civil & Env. Eng., University of Melbourne, Australia
b School of Engineering, University of Newcastle, Australia
c School of Geography, University of Leeds, United Kingdom
d Hydrological Sciences Branch, NASA GSFC, USA

2. Koster et al., JHM, 2000 Christoph Rüdiger AGU May 2004
Soil moisture controls weather
Need to properly initialise SM for use in LSM
Especially true for areas like Amazon, Sahel, SE Asia (ET)
Problems with remote sensing of SM in these areas
Koster et al., JHM, 2000
Christoph Rüdiger
AGU May 2004

3. Christoph Rüdiger
AGU May 2004

4. Goulburn Catchment Newcastle Sydney Melbourne Christoph Rüdiger
Geography, Size etc., Location, Data
Melbourne
0km
1000km
Christoph Rüdiger
AGU May 2004

5. Goulburn Catchment Streamgauge Climate Soil Moisture
Christoph Rüdiger
AGU May 2004

6. 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

7. Internal routing Velocity weight v-1 Travel time Tpi Christoph Rüdiger
AGU May 2004

8. Synthetic Experiment Variational 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

9. Results “Experiment 1” Discharge Soil Moisture Christoph Rüdiger
AGU May 2004

10. Results “Experiment 1”
Christoph Rüdiger
AGU May 2004

11. Results “Experiment 2” Discharge Soil Moisture Christoph Rüdiger
AGU May 2004

12. 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

13. 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