Effect of model resolution on a regional climate model simulation over southeast Australia
Type
ArticleAuthors
Evans, J. P.
McCabe, Matthew

KAUST Department
Biological and Environmental Sciences and Engineering (BESE) DivisionEnvironmental Science and Engineering Program
Water Desalination and Reuse Research Center (WDRC)
Date
2013-03-26Permanent link to this record
http://hdl.handle.net/10754/555783
Metadata
Show full item recordAbstract
Dynamically downscaling climate projections from global climate models (GCMs) for use in impacts and adaptation research has become a common practice in recent years. In this study, the CSIRO Mk3.5 GCM is downscaled using the Weather Research and Forecasting (WRF) regional climate model (RCM) to medium (50 km) and high (10 km) resolution over southeast Australia. The influence of model resolution on the present-day (1985 to 2009) modelled regional climate and projected future (2075 to 2099) changes are examined for both mean climate and extreme precipitation characteristics. Increasing model resolution tended to improve the simulation of present day climate, with larger improvements in areas affected by mountains and coastlines. Examination of circumstances under which increasing the resolution decreased performance revealed an error in the GCM circulation, the effects of which had been masked by the coarse GCM topography. Resolution modifications to projected changes were largest in regions with strong topographic and coastline influences, and can be large enough to change the sign of the climate change projected by the GCM. Known physical mechanisms for these changes included orographic uplift and low-level blocking of air-masses caused by mountains. In terms of precipitation extremes, the GCM projects increases in extremes even when the projected change in the mean was a decrease: but this was not always true for the higher resolution models. Thus, while the higher resolution RCM climate projections often concur with the GCM projections, there are times and places where they differ significantly due to their better representation of physical processes. It should also be noted that the model resolution can modify precipitation characteristics beyond just its mean value.Citation
Effect of model resolution on a regional climate model simulation over southeast Australia 2013, 56 (2):131 Climate ResearchPublisher
Inter-Research Science CenterJournal
Climate ResearchDOI
10.3354/cr01151Additional Links
http://www.int-res.com/abstracts/cr/v56/n2/p131-145/ae974a485f413a2113503eed53cd6c53
10.3354/cr01151