Application of a Distributed Hydrological Model to Detect Hydrological Effect on Gravity

1
Application of a Distributed Hydrological
Modelto DetectHydrological Effect on Gravity

• Shaakeel Hasan
• Hydrology and Quantitative Water Management
  Group, Wageningen University, Netherlands
• Jan Boll
• Department of Biological and Agricultural
  Engineering, University of Idaho, USA
• Peter A. Troch
• Hydrology and Quantitative Water Management
  Group, Wageningen University, Netherlands
• Corinna Kroner
• Institute of Geosciences, Friedrich-Schiller-Unive
  rsity Jena, Germany

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Background (gravimetry)
GRACE
Global Geodynamics Project Superconducting
gravimeter Accuracy 1 nm/s2 2.5 mm water Range
of change in gravity residuals 40 nm/s2 Max.
variation in gravity residuals (hourly) 10 nm/s2.
GGP
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Problem description

• Moxa Geodynamic Observatory

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Time series analysis

• Exploratory data analysis
• Clear response in gravity to precipitation events
• Possible response in gravity to
  evapotranspiration as function of humidity,
  temperature wind speed!
• Steep decrease (related to precipitation)
• Gradual increase (related to evapotranspiration!)

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Time series analysis
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Time series analysis
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Time series analysis

• Fourier analysis
• 12 hr. periodicity for ground water and gravity
  residuals
• More periodic component in gr. res.

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Model description (Soil Moisture Routing (SMR)
Model)

• Based on publicly available data
• geology and soils
• land use and topography (DEM)
• climate data
• Underlying hydrologic process
• Variable source area
• Lateral flow based on Darcys law
• Saturation excess runoff

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Model description (Mass balance for each cell)
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Model description (Moxa watershed)

• Area 3 km2
• Grid 20 X 20 m.
• Max slope 68
• Min slope 0
• Data
• Precipitation
• Humidity
• Temperature
• Illuminance
• ET coefficient
• Gravity residual

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Initial result (modeled and measured gravity
residual)
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Initial result (modeled and measured gravity
residual zoomed)
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Initial result (modeled and measured gravity
residual zoomed)
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Initial result (modeled and measured gravity
residual zoomed)
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Remarks about initial model result

• Model agrees partially with gravity residuals.
• Storage changes close to gravimeter area are
  important, however the domain is not researched
  yet.
• Before concluding about hydrological effects, we
  need to understand the hydrology of the
  catchment.
• Installation of some instruments was recently
  done, but data are not yet applied in analysis.

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Final remarks

• In-situ gravity measurements of this kind may
  offer an intriguing new look at hydrological
  processes.
• A new way of modeling, and looking into the
  stocks and fluxes of the model domain.
• Getting hydrological effects on gravity would
  contribute to
• Prediction in Ungauged Basin.
• Other branches of Geo-science.