Characterizing and comparing the control-run variability of eight coupled AOGCMs and of observations. Part 2: precipitation

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Article  

  Climate Dynamics
Publisher: Springer-Verlag Heidelberg
ISSN: 0930-7575 (Paper) 1432-0894 (Online)
DOI: 10.1007/s00382-003-0358-9
Issue: Volume 21, Numbers 7-8

Date:  December 2003
Pages: 647 - 658  
Characterizing and comparing the control-run variability of eight coupled AOGCMs and of observations. Part 2: precipitation
L. D. D. Harvey1

(1)  Department of Geography, University of Toronto, 100 St. George Street, Toronto M5S 3G3, Canada,  

Received: 17 December 2002  Accepted: 20 August 2003  Published online: 24 October 2003

Abstract   This study examines the variability of annual-mean precipitation in eight AOGCMs and in observations using empirical orthogonal functions (EOFs). The leading mode of precipitation variability in both models and observations is centered around the low-latitude western Pacific Ocean and Indian Ocean, and is associated with the El Niño-Southern Oscillation (ENSO). The spatial pattern R 2 correlations between model and observed EOF1 range from 0.12 to 0.61. In the observations, the Southern Oscillation Index (SOI) is highly correlated (R 2 = 0.82) with the amplitude of precipitation EOF1, while model R 2 correlations range from 0.17 to 0.83. If grid points near to those used to compute the standard SOI are used to compute alternative SO indices, the correlation with the amplitude of EOF1 ranges from 0.40 to 0.90 when based on the index that maximizes the correlation. Spatial fields of the variation between local precipitation and the SOI or the North Atlantic Oscillation Index are also computed for each model and compared with the observed fields. The model fields have many important similarities with the observed fields.