1. Jeffrey Walker Australian Root Zone Soil Moisture: Assimilation of Remote Sensing Observations 1 Jeffrey Walker, 2 Nadia Ursino, 1 Rodger Grayson and 3 Paul Houser 1. Dept of Civil and Env Engg, University of Melbourne, Australia 2. Dept IMAGE, University of Padova, Italy 3. Hydrological Sciences Branch, NASA-GSFC, USA http://www.civenv.unimelb.edu.au/~jwalker

2. Jeffrey Walker The Situation Remote Sensing Satellite Soil Moisture Sensors Logger Soil Moisture Model [q, D ( ), ( )]   f     s (z) Stream Gauge

3. Jeffrey Walker Catchment Discretisation Hydrologic unit is the catchment  50x50 km 2

4. Jeffrey Walker SMMR Soil Moisture Observations Owe, de Jeu and Walker, TGRS 2001 79-87 86 79-85 Rüdiger and Walker

5. Jeffrey Walker Assimilation Results

6. Jeffrey Walker Soil Moisture Data

7. Jeffrey Walker Gauged Catchments 330 catchments but mostly coastal and/or dense veg

8. Jeffrey Walker NDVI Data

9. Jeffrey Walker Drought of 1982/83 NDVI (-) Soil Texture: Wilt Pt

10. Jeffrey Walker Anomalies

11. Jeffrey Walker Drought of 1982/83

12. Jeffrey Walker Anomalies

13. Jeffrey Walker Temporal Correlation

14. Jeffrey Walker Conclusions Mismatch between model output and available soil moisture data made it difficult to draw conclusions on improvement in soil moisture predictions. Need to make further investigations using the runoff data for low vegetation interior catchments – assumes model has correct dependence on soil moisture. An increase in correlation with NDVI data – provides encouragement for pursuing assimilation of AMSR-E data and the collection of appropriate ground-based soil moisture validation data.

15. Jeffrey Walker