Open AccessModulation in interannual sea ice patterns in the Southern Ocean in association with large‐scale atmospheric mode shift
Author(s) -
Udagawa Yusuke,
Tachibana Yoshihiro,
Yamazaki Koji
Publication year - 2009
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 - 10.1029/2009jd011807
Subject(s) - empirical orthogonal functions , teleconnection , climatology , spatial ecology , mode (computer interface) , pacific decadal oscillation , common spatial pattern , geology , atmospheric sciences , environmental science , modulation (music) , sea surface temperature , oscillation (cell signaling) , el niño southern oscillation , physics , ecology , statistics , mathematics , computer science , acoustics , biology , operating system , genetics
We verified that the synchronous propagations of the spatial patterns of sea ice concentration (SIC) of wave number 2 around the Antarctic occurred only for the period 1984 to 1994. An empirical orthogonal function (EOF) analysis of satellite data for 1979–2003 objectively demonstrates that the spatial pattern of SIC propagated eastward only in 1984–1994; in other years, it did not. Our results show that interannual variations in SIC patterns are associated with differences in the dominant large‐scale atmospheric patterns. In nonpropagating years, variance of the tropospheric Antarctic oscillation (AAO) predominated. However, in propagating years, the AAO variance was subdominant to that of the Pacific South American (PSA) teleconnection pattern having a 4 year period. Such periodic PSA enables the SIC anomalies to propagate eastward with a periodically reinforced dipole pattern. The shift of large‐scale atmospheric variability is one possible cause of the modulation in the SIC pattern. The switch of the atmospheric EOF leading mode from the PSA pattern to the AAO in the mid‐1990s corresponded to the modulation in the SIC pattern and supports the presence of the atmospheric climate shifts.