PUB Working Group 2 (WG2): MOPEX Working Group
Objectives
- To develop improved model parameter estimation techniques for ungaged basins
- To develop an international database of retrospective hydrometeorological data and basin characteristics data for a wide of climate and geophysiolo gical conditions
- To develop objective measures to evaluate the parameter estimate techniques and to understand parameter uncertainty
- To develop diagnostic tools to foster improved understanding of natural hydrologic processes at basin scales and related behaviour of hydrologic models
- To promote and facilitate the exchange of ideas and experiences on approaches to model parameter estimation for different climatic regimes
Having developed the necessary data sets, these
were used to study individual models using three parallel paths;
- The first path is
to make control runs with model parameters estimated using existing a priori parameter estimation procedures.
- The second path is to make model runs using calibrated or tuned values of selected model parameters: relationships are then developed between the calibrated parameters and basin climate, soils, vegetation and topographic characteristics. These relationships are used to define the new a priori parameters.
- The third path is to make new model runs using the new a priori parameter estimates.
A major effort involves developing a systematic procedure for automatic calibration of selected model parameters and to apply this procedure to a large number of basins in different climatological and hydrologic settings. This allows empirical relationships to be sought between the parameters and various characteristics of soils, vegetation and climate.
Achievement of the parameter estimation goal is established in two steps.
- The first is to measure how much of the potential improvement in model performance when operated in calibration path is obtained when the model is operated using new a priori parameters. This step uses the same data sets as were used to develop the new a priori parameter estimates.
- The second step is to demonstrate that new a priori techniques produce better model results than existing a priori techniques for basins not used to develop the new a priori techniques. The outcome of this step has very strong implications for Prediction in Ungauged Basins (PUB).
There are a broad range of science questions to be investigated by MOPEX-PUB
workgroup, categorised as follows:
- Model calibration issues
- Model evaluation and diagnostic tools
- Data for model calibration and validation
- Quantification of uncertainty in hydrologic models
- Regionalization of model parameters
- Parameter transferability issues: From gauged to ungauged basins
Key Participants: