Convectively coupled Kelvin waves in CMIP5 coupled climate models

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• 作者：Lu Wang ; Tim Li
• 关键词：Kelvin wave ; Precipitation ; Climate model ; CMIP5
• 刊名：Climate Dynamics
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：48
• 期：3-4
• 页码：767-781
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Geophysics/Geodesy; Climatology; Oceanography;
• 出版者：Springer Berlin Heidelberg
• ISSN：1432-0894
• 卷排序：48

文摘

This study provided a quantitative evaluation of convectively coupled Kelvin waves (CCKWs) over the Indian Ocean and the Pacific Ocean simulated by 20 coupled climate models that participated in Coupled Model Intercomparison Project phase 5. The two leading empirical orthogonal function (EOF) modes of filtered daily precipitation anomalies are used to represent the eastward propagating CCKWs in both observations and simulations. The eigenvectors and eigenvalues of the EOF modes represent the spatial patterns and intensity of CCKWs respectively, and the lead–lag relationship between the two EOF principle components describe the phase propagation of CCKWs. A non-dimensional metric was designed in consideration of all the three factors (i.e., pattern, amplitude and phase propagation) for evaluation. The relative rankings of the models based on the skill scores calculated by the metric are conducted for the Indian Ocean and the Pacific Ocean, respectively. Two models (NorESM1-M and MPI-ESM-LR) are ranked among the best 20 % for both the regions. Three models (inmcm4, MRI-CGCM3 and HadGEM2-ES) are ranked among the worst 20 % for both the regions. While the observed CCKW amplitude is greater north of the equator in the Pacific, some models overestimate the CCKW ampliutde in the Southern Hemisphere. This bias is related to the mean state precipitation bias along the south Pacific convergence zone.