TY - JOUR
T1 - Calibration of a distributed hydrology and land surface model using energy flux measurements
AU - Larsen, Morten Andreas Dahl
AU - Refsgaard, Jens Christian
AU - Jensen, Karsten H.
AU - Butts, Michael B.
AU - Stisen, Simon
AU - Mollerup, Mikkel
N1 - Accepted for publication
PY - 2016
Y1 - 2016
N2 - In this study we develop and test a calibration approach on a
spatially distributed groundwater-surface water catchment model (MIKE
SHE) coupled to a land surface model component with particular focus on
the water and energy fluxes. The model is calibrated against time series
of eddy flux measurements from three sites of different land surface type
(agriculture, forest and meadow) and river discharge data from the 2500
km2 Skjern River catchment in Denmark. The approach includes initial
calibrations of three one-dimensional models representing the three land
surface types using the flux measurements for calibration. This step
provides initial values for the subsequent modelling and calibration at
catchment scale. To test the validity of the approach, two additional
catchment scale distributed simulations were performed with no
calibration and only calibration of the one-dimensional models,
respectively. In addition, a subsequent validation period was simulated.
A mean energy closure imbalance of 20% was seen for the three sites. For
the distributed simulations, the energy imbalance was accounted for by
two energy balance closure hypotheses ascribing the error to either
energy fluxes or net radiation. In general, the distributed calibration
approach improved model results substantially compared to using default
values (no calibration) or calibration of the one-dimensional models
only. For the distributed model simulations, the assumption regarding the
energy balance closure had a substantial impact on the parameter
sensitivities and on the simulated discharge and energy balance. During
calibration, the simulation with corrected energy fluxes showed better
performance on discharge than the simulation with corrected net radiation
whereas the reverse was true for the validation period. Regarding energy
fluxes, the simulation with corrected net radiation was superior in both
the calibration and validation period.
AB - In this study we develop and test a calibration approach on a
spatially distributed groundwater-surface water catchment model (MIKE
SHE) coupled to a land surface model component with particular focus on
the water and energy fluxes. The model is calibrated against time series
of eddy flux measurements from three sites of different land surface type
(agriculture, forest and meadow) and river discharge data from the 2500
km2 Skjern River catchment in Denmark. The approach includes initial
calibrations of three one-dimensional models representing the three land
surface types using the flux measurements for calibration. This step
provides initial values for the subsequent modelling and calibration at
catchment scale. To test the validity of the approach, two additional
catchment scale distributed simulations were performed with no
calibration and only calibration of the one-dimensional models,
respectively. In addition, a subsequent validation period was simulated.
A mean energy closure imbalance of 20% was seen for the three sites. For
the distributed simulations, the energy imbalance was accounted for by
two energy balance closure hypotheses ascribing the error to either
energy fluxes or net radiation. In general, the distributed calibration
approach improved model results substantially compared to using default
values (no calibration) or calibration of the one-dimensional models
only. For the distributed model simulations, the assumption regarding the
energy balance closure had a substantial impact on the parameter
sensitivities and on the simulated discharge and energy balance. During
calibration, the simulation with corrected energy fluxes showed better
performance on discharge than the simulation with corrected net radiation
whereas the reverse was true for the validation period. Regarding energy
fluxes, the simulation with corrected net radiation was superior in both
the calibration and validation period.
U2 - 10.1016/j.agrformet.2015.11.012
DO - 10.1016/j.agrformet.2015.11.012
M3 - Journal article
VL - 217
SP - 74
EP - 88
JO - Agricultural and Forest Meteorology
JF - Agricultural and Forest Meteorology
SN - 0168-1923
ER -