announcement header

WCIASP/IMAGe Seminar Series:
The Production and Use of Information on Future Climate

Jens Hesselbjerg Christensen
Danish Meteorological Institute
May 18, 2010
Mesa Laboratory, Main Seminar Room
Lecture 10:30am

Weighting Regional Climate Models Based on Several Specific Metrics:
Exploring a Concept

An important new development within the European FP6 project ENSEMBLES has been to explore performance-based weighting of regional climate models. Until now, while no weighting has been applied in multi-RCM analyses, one could claim that an assumption of “equal weight” has implicitly applied. At the same time, it is evident that different RCMs give results of a varying degree of realism, e.g. related to extremes. It is not straightforward to construct, assign and combine metrics of model performance. Rather, there is a considerable degree of subjectivity both to the definition of the metrics and to the way these are combined into weights. This does not mean that weighting, however exploratory, would not be meaningful. Rather, it stresses that the assumptions and choices behind the weights need to be recognized and taken into account. Here I will discuss the applicability of combining a set of six specifically designed RCM weights to produce one model index producing combined climate change information from the range of RCMs used within ENSEMBLES.