Use of expert elicitation to assign weights to climate and hydrological models in climate impact studies
- 1Geological Survey of Denmark and Greenland, Copenhagen, Denmark
- 2University of Eastern Finland, Joensuu, Finland
- 3Swedish Meteorological and Hydrological Institute, Norrköping, Sweden
- 4Université Paris-Saclay, INRAE, HYCAR Research Unit, Antony, France
- 5University of Granada, Granada, Spain
- 6European Environment Agency, Copenhagen, Denmark
- 7Fluvial Dynamics and Hydrology Research Group, Andalusian Institute for Earth System Research (IISTA), University of Córdoba, Córdoba, Spain
- 8Department of Agronomy, Unit of Excellence María de Maeztu (DAUCO), University of Córdoba, Córdoba, Spain
- 9Physics of Ice, Climate and Earth, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
- 10NORCE Norwegian Research Centre, The Bjerknes Centre for Climate Research, Bergen, Norway
- 11Danish Meteorological Institute, Copenhagen, Denmark
- 12INRAE, UR RiverLy, Villeurbanne Cedex, France
- 13Groupe de Météorologie de Grande Échelle et Climat, Centre National de Recherches Météorologiques, Météo-France, Toulouse, France
- 14Département des sciences de la Terre et de l'atmosphère, Université du Québec à Montréal, Montréal, Québec, Canada
- 15Barcelona Supercomputing Center, Barcelona, Spain
- 16ICREA, Pg. Lluís Companys 23, Barcelona, Spain
- 17University of Genoa, Genoa, Italy
- 18BRGM, Univ. Montpellier, Montpellier, France
Abstract. Various methods are available for assessing uncertainties in climate impact studies. Among such methods, model weighting by expert elicitation is a practical way to provide a weighted ensemble of models for specific real-world impacts. The aim is to decrease the influence of improbable models in the results and easing the decision-making process. In this study both climate and hydrological models are analyzed and the result of a research experiment is presented using model weighting with the participation of 6 climate model experts and 6 hydrological model experts. For the experiment, seven climate models are a-priori selected from a larger Euro-CORDEX ensemble of climate models and three different hydrological models are chosen for each of the three European river basins. The model weighting is based on qualitative evaluation by the experts for each of the selected models based on a training material that describes the overall model structure and literature about climate models and the performance of hydrological models for the present period. The expert elicitation process follows a three-stage approach, with two individual elicitations of probabilities and a final group consensus, where the experts are separated into two different community groups: a climate and a hydrological modeller group. The dialogue reveals that under the conditions of the study, most climate modellers prefer the equal weighting of ensemble members, whereas hydrological impact modellers in general are more open for assigning weights to different models in a multi model ensemble, based on model performance and model structure. Climate experts are more open to exclude models, if obviously flawed, than to put weights on selected models in a relatively small ensemble. The study shows that expert elicitation can be an efficient way to assign weights to different hydrological models, and thereby reduce the uncertainty in climate impact. However, for the climate model ensemble, comprising seven models, the elicitation in the format of this study could only reestablish a uniform weight between climate models.
Eva Sebok et al.
Eva Sebok et al.
Eva Sebok et al.
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