HR: 1340h
AN: GC43A-0943    [Abstracts]
TI: Assessment of the use of Current Climate Patterns to Evaluate Regional Enhanced Greenhouse Response Patterns of Climate Models
AU: * Whetton, P H
EM: penny.whetton@csiro.au
AF: CSIRO Marine and Atmospheric Research, Private Bag 1, Aspendale, Vic 3195, Australia
AU: Macadam, I
EM: ian.macadam@csiro.au
AF: CSIRO Marine and Atmospheric Research, Private Bag 1, Aspendale, Vic 3195, Australia
AU: Bathols, J M
EM: janice.bathols@csiro.au
AF: CSIRO Marine and Atmospheric Research, Private Bag 1, Aspendale, Vic 3195, Australia
AU: O'Grady, J G
EM: julian.o'grady@csiro.au
AF: CSIRO Marine and Atmospheric Research, Private Bag 1, Aspendale, Vic 3195, Australia
AB: Output of multiple global climate models is often considered in the generation of regional climate change projections. The reliability of the regional responses of models to enhanced greenhouse forcing is often assessed by comparing their current climate simulation against observations. The rationale for this assessment is that a model should be able to reproduce key aspects of the present climate if it is to be used to provide guidance for future changes in climate. However, the best way to assess the current climate of a model is unresolved. One can assess regional average or grid point model biases for the variable and season for which projections are to be prepared. However, a model that performs well for a target variable, season and location, may perform poorly for another variable, season or location, in which case model processes would be suspect. Other approaches consider spatial patterns and multiple variables, but this then raises the issue of how large an area the patterns should cover and what set of variables should be considered. We demonstrate how such a pattern-based approach can be evaluated by investigating the relationship between inter-model similarity in patterns of current regional climate and inter-model similarity in patterns of regional enhanced greenhouse response using data from the CMIP3 multi-model database. By making the assumption that the real world behaves like a typical climate model, we can use these results to assess whether the testing of the current climate patterns of the models against observations can be used to discriminate amongst enhanced greenhouse results of the models. Correlations of moderate magnitude are common in our results, indicating the value of testing the current regional climate simulation of models. Notably, relationships vary significantly regionally (e.g. are weakest in the tropics), cross variables (e.g. current climate mean sea level pressure is related to temperature and precipitation change in some extra-tropical regions) and can be insensitive to whether the current climate is assessed in the region concerned or globally. The presentation will also consider how the approach may be applied to performance-weighting of models in the generation of regional climate projections and in the assessment of the independence of output from different models.
UR: http://www.agu.org/journals/gl/gl0714/2007GL030025/2007GL030025.pdf
DE: 1626 Global climate models (3337, 4928)
DE: 1637 Regional climate change
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 3337 Global climate models (1626, 4928)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting