TY - JOUR
T1 - The Antarctic circumpolar wave and its seasonality
T2 - Intrinsic travelling modes and El Niño–Southern Oscillation teleconnections
AU - Wang, Xinyang
AU - Giannakis, Dimitrios
AU - Slawinska, Joanna
N1 - Funding Information:
information National Science Foundation, Grant/Award Number: AGS-1430051, DMS-1521775, 1551489; Office of Naval Research, Grant/Award Number: 25-74200-F7112; Office of Naval Research Global, Grant/Award Number: N00014-14-0150D.G. acknowledges support from ONR MURI grant 25-74200-F7112, ONR grant N00014-14-0150, and NSF grant DMS-1521775. X.W. was supported as a PhD student from the last two grants. J. Slawinska received support from NSF EAGER grant 1551489. The CCSM4 data were downloaded from the Earth System Grid website (http://www.earthsystemgrid.org). The HadISST data were downloaded from the Met Office Hadley Centre website (http://www.metoffice.gov.uk/hadobs/hadisst/). We thank Mitch Bushuk, Malte Stuecker, and Xiaojun Yuan for stimulating conversations.
Funding Information:
D.G. acknowledges support from ONR MURI grant 25-74200-F7112, ONR grant N00014-14-0150, and NSF grant DMS-1521775. X.W. was supported as a PhD student from the last two grants. J. Slawinska received support from NSF EAGER grant 1551489. The CCSM4 data were downloaded from the Earth System Grid website (http://www. earthsystemgrid.org). The HadISST data were downloaded from the Met Office Hadley Centre website (http://www. metoffice.gov.uk/hadobs/hadisst/). We thank Mitch Bushuk, Malte Stuecker, and Xiaojun Yuan for stimulating conversations.
Funding Information:
National Science Foundation, Grant/Award Number: AGS-1430051, DMS-1521775, 1551489; Office of Naval Research, Grant/Award Number: 25-74200-F7112; Office of Naval Research Global, Grant/Award Number: N00014-14-0150
Publisher Copyright:
© 2018 Royal Meteorological Society
PY - 2019/2/1
Y1 - 2019/2/1
N2 - Interannual variability in the Southern Ocean is investigated via nonlinear Laplacian spectral analysis (NLSA), an objective eigendecomposition technique for nonlinear dynamical systems that can simultaneously recover multiple timescales from data with high skill. Applied to modelled and observed sea surface temperature and sea ice concentration data, NLSA recovers the wavenumber-2 eastwards propagating signal corresponding to the Antarctic circumpolar wave (ACW). During certain phases of its lifecycle, the spatial patterns of this mode display a structure that can explain the statistical origin of the Antarctic dipole pattern. Another group of modes have combination frequencies consistent with the modulation of the annual cycle by the ACW. Further examination of these newly identified modes reveals that they can have either eastwards or westwards propagation, combined with meridional pulsation reminiscent of sea ice reemergence patterns. Moreover, they exhibit smaller-scale spatial structures and explain more Indian Ocean variance than the primary ACW modes. We attribute these modes to teleconnections between ACW and the tropical Indo-Pacific Ocean; in particular, fundamental El Niño–Southern Oscillation (ENSO) modes and their associated combination modes with the annual cycle recovered by NLSA. Another mode extracted from the Antarctic variables displays an eastwards propagating wavenumber-3 structure over the Southern Ocean, but exhibits no significant correlation to interannual Indo-Pacific variability.
AB - Interannual variability in the Southern Ocean is investigated via nonlinear Laplacian spectral analysis (NLSA), an objective eigendecomposition technique for nonlinear dynamical systems that can simultaneously recover multiple timescales from data with high skill. Applied to modelled and observed sea surface temperature and sea ice concentration data, NLSA recovers the wavenumber-2 eastwards propagating signal corresponding to the Antarctic circumpolar wave (ACW). During certain phases of its lifecycle, the spatial patterns of this mode display a structure that can explain the statistical origin of the Antarctic dipole pattern. Another group of modes have combination frequencies consistent with the modulation of the annual cycle by the ACW. Further examination of these newly identified modes reveals that they can have either eastwards or westwards propagation, combined with meridional pulsation reminiscent of sea ice reemergence patterns. Moreover, they exhibit smaller-scale spatial structures and explain more Indian Ocean variance than the primary ACW modes. We attribute these modes to teleconnections between ACW and the tropical Indo-Pacific Ocean; in particular, fundamental El Niño–Southern Oscillation (ENSO) modes and their associated combination modes with the annual cycle recovered by NLSA. Another mode extracted from the Antarctic variables displays an eastwards propagating wavenumber-3 structure over the Southern Ocean, but exhibits no significant correlation to interannual Indo-Pacific variability.
KW - Antarctic circumpolar wave
KW - ENSO teleconnections
KW - seasonal cycle
KW - spatio-temporal patterns
KW - time series analysis
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U2 - 10.1002/joc.5860
DO - 10.1002/joc.5860
M3 - Article
AN - SCOPUS:85055675421
SN - 0899-8418
VL - 39
SP - 1026
EP - 1040
JO - International Journal of Climatology
JF - International Journal of Climatology
IS - 2
ER -