Diagnostic calibration of a hydrological model in a mountain area by hydrograph partitioning

Abstract

Abstract. Hydrological modeling can exploit informative signatures extracted from long time sequences of observed streamflow for parameter calibration and model diagnosis. In this study we explore the diagnostic potential of hydrograph partitioning for model calibration in mountain areas, where meltwater from snow and glaciers is an important source for river runoff (in addition to rainwater). We propose an indexbased method to partition the hydrograph according to dominant runoff water sources, and a diagnostic approach to calibrate a mountain hydrological model. First, by accounting for the seasonal variability of precipitation and the altitudinal variability of temperature and snow/glacier coverage, we develop a set of indices to indicate the daily status of runoff generation from each type of water source (i.e., glacier meltwater, snow meltwater, rainwater, and groundwater). Second, these indices are used to partition a hydrograph into four parts associated with four different combinations of dominant water sources (i.e., groundwater, groundwater + snow meltwater, groundwater + snow meltwater + glacier meltwater, and groundwater + snow meltwater + glacier meltwater + rainwater). Third, the hydrological model parameters are grouped by the associated runoff sources, and each group is calibrated to match the corresponding hydrograph partition in a stepwise and iterative manner. Similar to use of the regime curve to diagnose seasonality of streamflow, the hydrograph partitioning curve based on a dominant runoff water source (more briefly called the partitioning curve, not necessarily continuous) can serve as a diagnostic signature that helps relate model performance to model components. The proposed methods are demonstrated via application of a semi-distributed hydrological model (THREW, Tsinghua Representative Elementary Watershed) to the Tailan River basin (TRB) (1324 km 2 ) in the Tianshan Mountains of China. Results show that the proposed calibration approach performed reasonably well. Cross-validation and comparison to an automatic calibration method indicated its robustness.

Using isotopes to constrain water flux and age estimates in snow-influenced catchments using the STARR (Spatially distributed Tracer-Aided Rainfall–Runoff) model

“…The model allows for water source appointment, i.e. in what part of the catchment and from which model compartment the runoff is being generated (animation S1), comparable to information that can be gained from data-driven hydrograph separation techniques (Rodhe, 1981;Laudon et al, 2002;He et al, 2015). Estimates of stream water age give comparative, integrated signals of what runoff generation processes dominate in the catchment and the timing of their seasonal activation.…”

“…2.2, and the radiation terms are adjusted to the influence of slope, aspect, hillshading, and canopy sheltering. Tree canopy snow interception and unloading are simulated after Hedstrom and Pomeroy (1998). The isotopic ratio of the snowpack is linked to snowpack water balance simulations with the following assumptions and conceptualizations.…”

HESS Opinions: Advocating process modeling and de-emphasizing parameter estimation

“…This step may not generally be necessary for physically based distributed models, because their parameters are usually likely to be sensitive; however, in my work with the WetSpa model, I found it appropriate to fix one insensitive parameter (parameter Kg m ). Similarly, Roux et al (2011) and He et al (2015) also report fixing insensitive parameters of their physically based models (MARINE and THREW).…”

“…In some cases, the model parameters and/or processes will be required to conform with organizing principles such as optimality, landscape evolution laws, and Horton laws of stream networks (e.g., the Horton number of bifurcation), and a higher level water balance model (a regional or global model) should be satisfied. As an example of the latter, Schaefli and Huss (2011) used glacier mass balance data to constrain the parameter A. Bahremand: Advocating process modeling and de-emphasizing parameter estimation uncertainty for their hydrological model in a glaciered basin (see also He et al, 2015). For the purpose of developing a community hydrological model, a universal water balance model can be used to establish constraints on our local model and its parameters.…”

Comparison of Precipitation and Streamflow Correcting for Ensemble Streamflow Forecasts

“…It is a semi-distributed hydrological model which uses the representative elementary watershed approach to conceptualize a watershed [44]. This model has been effectively used in many basins both in the United States and China [45][46][47]. Further, the detailed description and theoretical background of the THREW model can be found in Tian et al [43,47].…”