CONTROL OF COUPLING MASS BALANCE ERROR IN THE CATHY MODEL Department of Engineering “Enzo Ferrari,” University of Modena and Reggio Emilia Marcello Fiorentini Stefano Orlandini, Claudio Paniconi Workshop on Coupled Hydrological Modeling 23-24 September 2015 (Padua)
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CONTROL OF
COUPLING MASS BALANCE ERROR IN THE CATHY MODEL
Department of Engineering “Enzo Ferrari,” University of Modena and Reggio Emilia
- Control of Coupling Mass Balance Error in the CATHY model -
Sloping plane • Sensitivity of subsurface and coupling error to time step size • Sensitivity of surface error to mesh size
Sensitivity of mass balance errors to recession limb
Workshop on Coupled Hydrological Modeling
- Control of Coupling Mass Balance Error in the CATHY model -
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Heuristic time step size control
Normalized variation of the degree of coupling index
Modified time step size control
Workshop on Coupled Hydrological Modeling
- Control of Coupling Mass Balance Error in the CATHY model -
Workshop on Coupled Hydrological Modeling
- Control of Coupling Mass Balance Error in the CATHY model -
• interpolation of exchange fluxes
• surface water propagation
• cell water balance
• reconstruction of ponding heads
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Workshop on Coupled Hydrological Modeling
- Control of Coupling Mass Balance Error in the CATHY model -
Interpolation exchange fluxes
• geometric interpolation
• new interpolation algorithm
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Workshop on Coupled Hydrological Modeling
- Control of Coupling Mass Balance Error in the CATHY model -
CATHY modifications: • original code (O) • modified time step control strategy (TC) • new node-to-cell interpolation algorithm (IA) • combination between TC and IA (IT)
Workshop on Coupled Hydrological Modeling
- Control of Coupling Mass Balance Error in the CATHY model -
CATHY modifications: • original code (O) • modified time step control strategy (TC) • new node-to-cell interpolation algorithm (IA) • combination between TC and IA (IT)
Results: • Reduction of surface error (up to 97%) • Faster recession limbs
Workshop on Coupled Hydrological Modeling
- Control of Coupling Mass Balance Error in the CATHY model -
Conclusion
• Sources of mass balance errors in CATHY were analyzed • Global indices were presented to describe the hydrologic response of water basins
• Modified algorithms to control the time step size were presented • A new interpolation algorithm to pass exchange fluxes from surface to subsurface compartment was introduced
• Mesh size with local refinements will be investigated
• Application to real water basins
Workshop on Coupled Hydrological Modeling
- Control of Coupling Mass Balance Error in the CATHY model -