GRACE in the MDB by t858OR

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									 GRACE in the Murray-Darling Basin: integrating
remote sensing with field monitoring to improve
          hydrologic model prediction

                                 Kevin M. Ellett
Department of Civil and Environmental Engineering, University of Melbourne, Australia
                       and USGS WRD Sacramento, California


           Colleagues: Jeffrey Walker, Rodger Grayson, Adam Smith
                         and Matt Rodell (NASA-GSFC)
                  Outline

   Motivation for Research
   Contributions from GRACE
   Research Approach
   Preliminary Results
          Motivation for Research
 Modeling hydrological
  processes at the
  catchment-scale
 Soil moisture is a key
  component in the
  terrestrial water and
  energy balance
 Primary controls on soil
  moisture distribution
    climate, soils, vegetation,
     topography
 Scaling of soil moisture
  and hydrological
  processes?

                                   Western and Grayson, 1998
         Motivation for Research
 Current policy initiatives on
  sustainable water resource
  management in Australia
   – Murray-Darling Basin
     (MDB)
 Land clearing has resulted
  in devastating impacts
  from salinity
   – Long-term increase in
     terrestrial water storage
   – Re-vegetation to
     reverse this trend
  GRACE Contributions in the MDB
 Measuring the trend in storage change
  – Re-vegetation
  – Limited 5 year lifespan
 Assessment of regional-scale hydrological models
  – Water balance closure
  – Model bias
 Can GRACE help to improve modeling at the
  catchment-scale?
  – Scaling
                Objectives

1) GRACE “validation” (comparison) from an
   observational network
2) Examine the utility of GRACE observations
   at the catchment-scale
     Downscaling
                               Approach
1)       Installation of a ground-based measurement network for
         monitoring changes in gravity and terrestrial water
         storage
          Nested catchment and grid-based designs provide data at 4
           different scales using 46 total sites
2)       Development of a modelling framework for the
         downscaling and assimilation of GRACE data into a
         catchment-based land surface model
3)       Assessing the utility of GRACE by comparing model
         results with and without GRACE data assimilation to the
         measurement network
          Results will depend on downscaling approach, model physics,
           data assimilation, and observations- uncertainty in each
           component
           a)   Testing of alternative model with simple water balance
                parameterization allowing automated calibration
           b)   Testing of alternative downscaling schemes
Murray-Darling Basin and the
 Murrumbidgee Catchment
MDB and Murrumbidgee
Average Annual Precipitation (mm)
  MDB and Murrumbidgee
Annual Actual Evapotranspiration (mm)
     MDB and Murrumbidgee
Precipitation minus Evapotranspiration (mm)
MDB and Murrumbidgee
  Surface Water Storages
Murrumbidgee Monitoring Network

                                   Yanco Study Area
                                   (50km x 50km Grid)

                Irrigation Areas

                                                        Kyeamba Ck. Study Area
Monitoring Site Instrumentation


                     Logger
                                                          Gravity
                              Raingauge
                                                          monitoring with
                                                          CG-3M on stable
                                                          platform
                     T107
                                                          Star pickets
               TDR       Backfilled
                         soil                             (2.5 m
                                      CS616               length)

                       Piezometer (water
                       level and neutron
                       probe)


                 Schematic diagram of instrumentation installed at
                 monitoring sites
Gravity Network Tied to Canberra SG
                                                                          Preliminary Results
                                            Catchment mean RZSM storage timeseries                                                                                                                                   Kyeamba sub-catchment (upper) - RZSM  loc - mean

                    200                                                                                                                                                                            60




                                                                                                                                                                         Total RZSM Storage (mm)
                                                                                                                                                                                                   40
RZSM Storage (mm)




                                                                                                                                                                                                   20                                                                                                                                          Ginn(GS)
                                                                                                                                                              Murr_day                                                                                                                                                                         Ginn(F)
                    150                                                                                                                                       Murr_mon                              0                                                                                                                                          Wait(SS)
                                                                                                                                                              Ky_day                                                                                                                                                                           Clark(GS)
                                                                                                                                                              Ky_mon                               -20                                                                                                                                         Palm(GS)

                                                                                                                                                                                                   -40


                    100                                                                                                                                                                            -60
                          1/11/2001


                                      1/01/2002


                                                  1/03/2002


                                                              1/05/2002


                                                                          1/07/2002


                                                                                      1/09/2002


                                                                                                  1/11/2002


                                                                                                              1/01/2003


                                                                                                                          1/03/2003


                                                                                                                                      1/05/2003


                                                                                                                                                  1/07/2003




                                                                                                                                                                                                         1/11/2001

                                                                                                                                                                                                                       1/01/2002

                                                                                                                                                                                                                                   1/03/2002

                                                                                                                                                                                                                                               1/05/2002

                                                                                                                                                                                                                                                           1/07/2002

                                                                                                                                                                                                                                                                       1/09/2002

                                                                                                                                                                                                                                                                                   1/11/2002

                                                                                                                                                                                                                                                                                               1/01/2003

                                                                                                                                                                                                                                                                                                           1/03/2003

                                                                                                                                                                                                                                                                                                                       1/05/2003

                                                                                                                                                                                                                                                                                                                                   1/07/2003
                                                                                                          Observed average monthly dS = 13.5 mm
                                                                                                          Annual amplitude approx. 50 mm
                  Conclusions

 Murray-Darling Basin is a reasonable candidate
  for GRACE validation/comparison
   – Signal dominated by soil moisture component
   – Magnitude?
 Modeling framework for testing the utility of
  GRACE is currently being developed
   – Catchment-based LSM [Koster et al., 2000]
   – Assimilation scheme for GRACE and AMSR-E
   – Development of alternative downscaling schemes and
     simple “bucket” model calibrated

								
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