HR: 16:00h
AN: A14A-03    [Abstracts]
TI: A Performance Comparison of Coupled and Uncoupled Versions of the Met Office Seasonal Prediction GCM
AU: * Graham, R J
EM: richard.graham@metoffice.gov.uk
AF: Met Office, FitzRoy Road, Exeter, United Kingdom
AU: Gordon, M
AF: Met Office, FitzRoy Road, Exeter, United Kingdom
AU: McLean, P J
AF: Met Office, FitzRoy Road, Exeter, United Kingdom
AU: Ineson, S
AF: Met Office, FitzRoy Road, Exeter, United Kingdom
AU: Huddleston, M R
AF: Met Office, FitzRoy Road, Exeter, United Kingdom
AU: Davey, M K
AF: Met Office, FitzRoy Road, Exeter, United Kingdom
AU: Brookshaw, A
AF: Met Office, FitzRoy Road, Exeter, United Kingdom
AU: Barnes, R T
AF: Met Office, FitzRoy Road, Exeter, United Kingdom
AB: The benefits of using coupled GCMs over two-tier AGCM systems for seasonal prediction to 6-month range will be explored using 43-year, 9-ensemble hindcast datasets generated as part of the EU project DEMETER. The CGCM and AGCM systems employed share the same atmospheric component and a performance comparison therefore provides insight into the skill benefits available from coupling atmosphere and ocean models. The two-tier AGCM is forced with predicted Sea Surface Temperature (SST) based on persistence of observed SST anomalies (SSTA). Analysis will be focussed on global and regional comparisons of long-term skill for probabilistic prediction of 2m temperature. In the tropics CGCM benefits are seen, as expected, in the tropical east Pacific and are associated with superior CGCM skill (relative to persisted SSTA) in predicting ENSO SST anomalies. However substantial benefits are also seen throughout the tropical belt in seasons associated with the peak and decay of ENSO activity, such benefits arise from representation of lagged teleconnection responses to ENSO in the tropical Atlantic and Indian Oceans. CGCM benefits are also found in extratropical regions. In this regard an investigation of CGCM skill benefits for prediction of spring season temperature in the European region will be described in which improved skill appears to derive from coupled model representation of linkage between the well documented North Atlantic SSTA tripole pattern and the North Atlantic Oscillation (NAO). This result provides encouraging evidence that use of coupled GCMs offers prospects for improving seasonal prediction in the extratropics through representation of coupled ocean-atmosphere processes in extratropical ocean basins, as well as through indirect impacts from improved prediction of ENSO and associated teleconnections.
DE: 3337 Numerical modeling and data assimilation
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 4522 El Ni¤o
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly