HR: 1340h
AN: A23B-0800    [Abstracts]
TI: An Appraisal of Storm Track Depictions in Coupled Simulations of the CCSM Version 3.0
AU: * Cullather, R I
EM: cullat@ldgo.columbia.edu
AF: Lamont-Doherty Earth Observatory at Columbia University, 61 Route 9W, Palisades, NY 10964-1707 United States
AB: The Community Climate System Model, Version 3.0 is the most recent release of the global coupled climate model produced by the CCSM community, and contains improved model physics particularly with regards to cloud and ice phase processes. Numerous multi-century control runs were conducted with CCSM-3.0 at several resolutions. The purpose of this study is to evaluate the representation of transient atmospheric circulation features in the CCSM-3.0 in comparison to observation. Cyclone climatologies are a useful method for evaluating climate models as they provide details on the synoptic time scale as opposed to monthly means which are more readily available. A feature-tracking algorithm of intermediate complexity is applied to the once-daily output sea level pressure fields of the CCSM-3.0 millennial integration for twenty years of the integration. These calculations are compared to a similar analysis using daily fields of the European Centre for Medium-Range Weather Forecasts 40-Years Re-Analysis (ERA-40). Both cyclonic and anticyclonic features are tracked for both hemispheres, and computed statics include feature trajectory, as well as genesis and lysis frequencies. The results highlight differences in model simulations with observation but also indicate improvement of the newer version of the model to the CCSM-2, which was evaluated in a previous study. A central question to be answered by this study is the overall effects of the higher spatial resolution in the T85 simulation versus T42 horizontal resolution.
DE: 3337 Numerical modeling and data assimilation
DE: 3349 Polar meteorology
DE: 3364 Synoptic-scale meteorology
DE: 3319 General circulation
DE: 1620 Climate dynamics (3309)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting