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Robust increase of the equatorial Pacific rainfall and its variability in a warmed climate
Author(s) -
Watanabe Masahiro,
Kamae Youichi,
Kimoto Masahide
Publication year - 2014
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 - 10.1002/2014gl059692
Subject(s) - precipitation , coupled model intercomparison project , climatology , environmental science , sea surface temperature , climate model , amplitude , magnitude (astronomy) , pacific decadal oscillation , climate change , atmospheric sciences , geology , meteorology , geography , physics , oceanography , quantum mechanics , astronomy
Regional pattern of the mean precipitation changes in the latter half of the 21st century ( Δ P ¯ ) has been interpreted in terms of mean precipitation in current climate and a magnitude of increase in mean sea surface temperature (SST). Here we use state‐of‐the‐art climate model ensembles from the Coupled Model Intercomparison Project Phase 5 (CMIP5) and present that the amplitude of the precipitation variability, relative to slowly varying mean precipitation, coherently increases with Δ P ¯ , anchored over the central equatorial Pacific where a large SST swing occurs during El Niño–Southern Oscillation (ENSO) cycles. This increase owes to skewed probability distribution of precipitation as well as an asymmetrical precipitation response to positive and negative in situ SST anomalies and is robust despite uncertainty in the future ENSO amplitude change. The CMIP5 model ensembles also give a robust estimate of the projected Δ P ¯over the central equatorial Pacific, showing a 7% increase per unit increase of global‐mean surface temperature. Observational constraints applied to the above relationship suggest that the amounts of increases in both mean precipitation and variability should be even larger than the model averages.