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Relative Roles of Preconditioning Moistening and Global Circumnavigating Mode on the MJO Convective Initiation During DYNAMO
Author(s) -
Chen Xingchao,
Zhang Fuqing
Publication year - 2019
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 - 10.1029/2018gl080987
Subject(s) - madden–julian oscillation , dynamo , convection , climatology , oscillation (cell signaling) , mode (computer interface) , atmospheric sciences , geology , environmental science , meteorology , physics , magnetic field , chemistry , biochemistry , quantum mechanics , computer science , operating system
Abstract The relative importance of preconditioning moistening and global circumnavigating mode in the convective initiation of the October 2011 Madden–Julian Oscillation (MJO) event observed during the Dynamics of the Madden–Julian Oscillation (DYNAMO) field campaign is investigated using a series of convection‐permitting regional model simulations. It is demonstrated that the MJO convective initiation is largely controlled by the global circumnavigating mode at the intraseasonal scales. Rapid moistening closely related to this eastward propagating mode a few days prior to the MJO active phase is crucial to the initiation of deep convection and enhanced rainfall. This moistening process nevertheless cannot be accurately described by the “discharge‐recharge” hypothesis, which speculates the importance a gradual moisture buildup over an approximately 2‐week period leading to the arrival of the active MJO phase.