The Climate-system Historical Forecast Project: Do stratosphere-resolving models make better seasonal climate predictions in boreal winter?

Using an international, multi-model suite of historical forecasts from the World Climate Research Programme (WCRP) Climate-system Historical Forecast Project (CHFP), we compare the seasonal prediction skill in boreal wintertime between models that resolve the stratosphere and its dynamics ('hig...

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Bibliographic Details
Published in:Quarterly Journal of the Royal Meteorological Society
Main Authors: Butler, A., Arribas, A., Athanassiadou, M., Baehr, J., Calvo, N., Charlton-Perez, A., Déqué, M., Domeisen, D., Fröhlich, K., Hendon, H., Imada, Y., Ishii, M., Iza, M., Karpechko, A., Kumar, A., Maclachlan, C., Merryfield, W., Müller, W., O'Neill, A., Scaife, A., Scinocca, J., Sigmond, M., Stockdale, T., Yasuda, T.
Format: Article in Journal/Newspaper
Language:English
Published: 2016
Subjects:
North Atlantic
North Atlantic oscillation
Online Access:http://hdl.handle.net/11858/00-001M-0000-002A-0F51-B
http://hdl.handle.net/11858/00-001M-0000-002A-65C6-4
Description
Summary:Using an international, multi-model suite of historical forecasts from the World Climate Research Programme (WCRP) Climate-system Historical Forecast Project (CHFP), we compare the seasonal prediction skill in boreal wintertime between models that resolve the stratosphere and its dynamics ('high-top') and models that do not ('low-top'). We evaluate hindcasts that are initialized in November, and examine the model biases in the stratosphere and how they relate to boreal wintertime (December-March) seasonal forecast skill. We are unable to detect more skill in the high-top ensemble-mean than the low-top ensemble-mean in forecasting the wintertime North Atlantic Oscillation, but model performance varies widely. Increasing the ensemble size clearly increases the skill for a given model. We then examine two major processes involving stratosphere-troposphere interactions (the El Niño/Southern Oscillation (ENSO) and the Quasi-Biennial Oscillation (QBO)) and how they relate to predictive skill on intraseasonal to seasonal time-scales, particularly over the North Atlantic and Eurasia regions. High-top models tend to have a more realistic stratospheric response to El Niño and the QBO compared to low-top models. Enhanced conditional wintertime skill over high latitudes and the North Atlantic region during winters with El Niño conditions suggests a possible role for a stratospheric pathway. © 2016 Royal Meteorological Society.

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