Open AccessRelationship between ENSO and northward propagating intraseasonal oscillation in the east Asian summer monsoon system
Author(s) -
Yun KyungSook,
Seo KyongHwan,
Ha KyungJa
Publication year - 2008
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2008jd009901
Subject(s) - climatology , anticyclone , rossby wave , geology , monsoon , walker circulation , sea surface temperature , el niño southern oscillation , atmospheric circulation , east asian monsoon , oceanography , atmospheric sciences
Observational studies are presented on the relationship between El Niño–Southern Oscillation (ENSO) and the northward propagating intraseasonal oscillation (NPISO) in the east Asian summer monsoon (EASM) system. The summer NPISO activity shows a significant correlation with the preceding winter extreme phase of ENSO cycles. A higher correlation appears during late summer, which is consistent with frequent heavy rainfall events at that time as revealed in some previous case studies. The westward expansion of broad anticyclonic circulation over the western North Pacific and the smaller cyclonic circulation around Korea and Japan are found to be associated with the NPISO activity. ENSO affects the late summer NPISO activity through an atmospheric bridge and wave propagation; the springtime Indian Ocean sea surface temperature warming induced by ENSO through the Walker circulation leads to the downward motion and suppressed convection over the Philippine Sea, and this generates the forced Rossby wave train, forming the above south‐to‐north low‐level circulation anomalies.