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Quantitative characterization of spurious numerical oscillations in 48 CMIP5 models
Author(s) -
Geil Kerrie L.,
Zeng Xubin
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl063931
Subject(s) - spurious relationship , climatology , classification of discontinuities , climate model , amplitude , environmental science , coupled model intercomparison project , oscillation (cell signaling) , orography , atmospheric sciences , statistical physics , meteorology , geology , climate change , physics , mathematics , statistics , precipitation , quantum mechanics , biology , genetics , mathematical analysis , oceanography
Spurious numerical oscillations (SNOs) (e.g., Gibbs oscillations) can appear as unrealistic spatial waves near discontinuities or sharp gradients in global model fields (e.g., orography) and have been a known problem in global models for decades. Multiple methods of oscillation reduction exist; consequently, the oscillations are presumed small in modern climate models and hence are rarely addressed in recent literature. Here we use two metrics to quantify SNOs in 13 variables from 48 Coupled Model Intercomparison Project Phase 5 models along a Pacific ocean transect near the Andes. Results show that 48% of nonspectral models and 95% of spectral models have at least one variable with SNO amplitude as large as, or greater than, atmospheric interannual variability. The impact of SNOs on climate simulations should be thoroughly evaluated and further efforts to substantially reduce SNOs in climate models are urgently needed.