The amplitude of decadal to multidecadal variability in precipitation simulated by state-of-the-art climate models

T. R. Ault, J. E. Cole, Scott St. George

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

We assess the magnitude of decadal to multidecadal (D2M) variability in Climate Model Intercomparison Project 5 (CMIP5) simulations that will be used to understand, and plan for, climate change as part of the Intergovernmental Panel on Climate Change's 5th Assessment Report. Model performance on D2M timescales is evaluated using metrics designed to characterize the relative and absolute magnitude of variability at these frequencies. In observational data, we find that between 10% and 35% of the total variance occurs on D2M timescales. Regions characterized by the high end of this range include Africa, Australia, western North America, and the Amazon region of South America. In these areas D2M fluctuations are especially prominent and linked to prolonged drought. D2M fluctuations account for considerably less of the total variance (between 5% and 15%) in the CMIP5 archive of historical (1850-2005) simulations. The discrepancy between observation and model based estimates of D2M prominence reflects two features of the CMIP5 archive. First, interannual components of variability are generally too energetic. Second, decadal components are too weak in several key regions. Our findings imply that projections of the future lack sufficient decadal variability, presenting a limited view of prolonged drought and pluvial risk.

Original languageEnglish (US)
Article numberL21705
JournalGeophysical Research Letters
Volume39
Issue number21
DOIs
StatePublished - Nov 1 2012

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climate models
climate modeling
drought
climate change
timescale
Amazon region (South America)
Intergovernmental Panel on Climate Change
simulation
energetics
projection
state of the art
project
estimates

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The amplitude of decadal to multidecadal variability in precipitation simulated by state-of-the-art climate models. / Ault, T. R.; Cole, J. E.; St. George, Scott.

In: Geophysical Research Letters, Vol. 39, No. 21, L21705, 01.11.2012.

Research output: Contribution to journalArticle

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