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Past‐ and present‐day Madden‐Julian Oscillation in CNRM‐CM5
Author(s) -
Song EunJi,
Seo KyongHwan
Publication year - 2016
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 - 10.1002/2016gl068771
Subject(s) - madden–julian oscillation , climatology , equator , anticyclone , coupled model intercomparison project , precipitation , forcing (mathematics) , environmental science , sea surface temperature , oscillation (cell signaling) , climate model , convection , geology , atmospheric sciences , meteorology , climate change , geography , oceanography , latitude , geodesy , biology , genetics
Madden‐Julian Oscillation (MJO) in the past (nineteenth century) and present day (twentieth century) is examined using preindustrial and historical experiments of Centre National de Recherches Météorologiques‐Coupled Models, version 5 (CNRM‐CM5) in Coupled Model Intercomparison Project Phase 5 (CMIP5). The present‐day MJO is stronger than the past MJO by 33% and it is ~10% more frequent. In particular, the MJO phases 4–7 signifying deep convection situated over the Maritime continent and western Pacific (WP) are considerably enhanced. These changes are due mainly to greenhouse gas forcing with little impact from nature forcing. Dynamical mechanisms for this change are investigated. A peculiar strengthening of MJO over WP comes from increased basic‐state sea surface temperature (SST) over the Central Pacific (CP) and EP. The increase in precipitation over WP results from both the response to enhanced SST over CP and the inverted Walker circulation induced by the EP and CP SST increase. The latter causes a pair of anticyclonic Rossby waves straddling the equator, leading to moisture convergence over WP.