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Earth‐atmosphere angular momentum exchange and ENSO: The rotational signature of the 1997–98 Event
Author(s) -
Dickey Jean O.,
Gegout Pascal,
Marcus Steven L.
Publication year - 1999
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 - 10.1029/1999gl900449
Subject(s) - angular momentum , atmosphere (unit) , physics , context (archaeology) , earth's rotation , atmospheric sciences , oscillation (cell signaling) , momentum (technical analysis) , event (particle physics) , southern oscillation , geophysics , computational physics , geology , el niño southern oscillation , climatology , astrophysics , meteorology , astronomy , classical mechanics , chemistry , paleontology , biochemistry , finance , economics
The impact of the 1997–1998 ENSO event is presented in context of axial Earth‐atmosphere angular momentum exchange utilizing length of day (LOD), Southern Oscillation Index (SOI) and atmospheric angular momentum (AAM) data from 1970 to 1998; comparisons are made with previous events. The analysis of equal‐area latitudinally belted AAM from the NCEP reanalysis (1958–98) reveals slow global coherent poleward propagation of angular momentum. These structures originate in the equatorial regions, penetrate into high latitudes and are bimodal in nature with variations centered at low‐frequency (LF ∼4.7 yr) and quasi‐biennial (QB ∼2.4 yr) periods. Analyses utilize both a recursive filter and multichannel singular spectrum analysis (M‐SSA).