Search Results

You are looking at 1 - 10 of 634 items for :

  • Arctic Oscillation x
  • Journal of the Atmospheric Sciences x
  • All content x
Clear All
Chaim I. Garfinkel, Tiffany A. Shaw, Dennis L. Hartmann, and Darryn W. Waugh

1. Introduction The strength of the Northern Hemisphere stratospheric wintertime polar vortex is highly variable. Although much of this variability is stochastic ( Holton and Mass 1976 ), Garfinkel et al. (2010) found that approximately 40% of the variability on interseasonal time scales may be linked to variability occurring outside of the polar stratosphere. One of the main sources of predictable external variability is the quasi-biennial oscillation (QBO). Arctic polar cap temperatures are

Full access
Mauro Dall’Amico and Joseph Egger

in surface weather ( Thompson and Wallace 2001 ; Thompson et al. 2002 ). The dynamical coupling of the troposphere with the stratosphere 1 in the NH is captured by the northern annular mode (NAM; see Thompson and Wallace 1998 ; Baldwin and Dunkerton 1999 ; Thompson and Wallace 2000) . In the winter stratosphere the annular mode is linked to the temperature and strength of the polar vortex. In the lowermost troposphere, the NAM appears as the Arctic Oscillation and, in particular, over the

Full access
Mario Sempf, Klaus Dethloff, Dörthe Handorf, and Michael V. Kurgansky

were initially motivated by the work of Sempf et al. (2005) , where the impact of orographic forcing and of zonal asymmetries in extratropical diabatic heating on the structure of the Arctic Oscillation (AO) was studied. There, it was necessary to force stationary waves in a physically correct manner, as far as possible. Therefore the nonzonal components of the radiative equilibrium temperature fields were adjusted in a way that, on the time mean, realistic patterns of nonzonal extratropical

Full access
H. L. Tanaka and Hiroki Tokinaga

1. Introduction Arctic oscillation (AO) advocated by Thompson and Wallace (1998) has attracted more attention in recent years. The AO is a north–south seesaw of the atmospheric mass between the arctic region poleward of 60°N and a surrounding zonal ring in midlatitudes. It is defined as a primary mode of an empirical orthogonal function (EOF) for the sea level pressure field in the Northern Hemisphere (NH). The spatial pattern of the AO is characterized by its zonally symmetric or “annular

Full access
H. L. Tanaka

1. Introduction The Arctic Oscillation (AO) postulated by Thompson and Wallace (1998 , 2000) has attracted more attention in recent years. The AO is a north–south seesaw of the atmospheric mass between the Arctic region poleward of 60°N and a surrounding zonal ring in the midlatitudes. It is defined as a primary mode of an empirical orthogonal function (EOF) for the sea level pressure field in the Northern Hemisphere. The spatial pattern of the AO is characterized by its zonally symmetric or

Full access
Jie Song

.1175/1520-0442(2002)015<1969:TNTSC>2.0.CO;2 Ambaum , M. H. P. , B. J. Hoskins , and D. B. Stephenson , 2001 : Arctic Oscillation or North Atlantic Oscillation? J. Climate , 14 , 3495 – 3507 , https://doi.org/10.1175/1520-0442(2001)014<3495:AOONAO>2.0.CO;2 . 10.1175/1520-0442(2001)014<3495:AOONAO>2.0.CO;2 Baldwin , M. P. , and T. J. Dunkerton , 1999 : Propagation of the Arctic Oscillation from the stratosphere to the troposphere . J. Geophys. Res. , 104 , 30 937 – 30 946 , https://doi.org/10.1029/1999JD

Open access
Jorgen S. Frederiksen and Hai Lin

studies have established robust phase relationships between tropical convection on the intraseasonal time scale and the development of Pacific–North America (PNA), Arctic Oscillation (AO), or North Atlantic Oscillation (NAO) teleconnection patterns. It seems of interest to examine whether these same phase relationships hold for the theoretical intraseasonal oscillation modes. As well, in observational studies such as LBD2009 wave-activity fluxes have been calculated to characterize the tropical

Full access
Joseph P. Clark and Steven B. Feldstein

.1175/JCLI-D-13-00642.1 . 10.1175/JCLI-D-13-00642.1 Francis , J. A. , and E. Hunter , 2006 : New insight into the disappearing Arctic sea ice . Eos, Trans. Amer. Geophys. Union , 87 , 509 – 511 , https://doi.org/10.1029/2006EO460001 . 10.1029/2006EO460001 Franzke , C. , S. Lee , and S. B. Feldstein , 2004 : Is the North Atlantic Oscillation a breaking wave? J. Atmos. Sci. , 61 , 145 – 160 , https://doi.org/10.1175/1520-0469(2004)061<0145:ITNAOA>2.0.CO;2 . 10

Free access
Joseph P. Clark and Steven B. Feldstein

of downward infrared radiation in the recent Arctic winter warming trend . J. Climate , 30 , 4937 – 4949 , https://doi.org/10.1175/JCLI-D-16-0180.1 . 10.1175/JCLI-D-16-0180.1 Holton , J. R. , and G. H. Hakim , 2013 : An Introduction to Dynamic Meteorology. 5th ed. Academic Press, 532 pp . 10.1016/B978-0-12-384866-6.00001-5 Hurrell , J. W. , Y. Kushnir , G. Ottersen , and M. Visbeck , 2003 : The North Atlantic Oscillation: Climate Significance and Environmental Impact

Free access
A. Deloncle, R. Berk, F. D’Andrea, and M. Ghil

authors obtained four statistically significant weather regimes: the two phases of the North Atlantic Oscillation (NAO + , NAO − ) and the two phases of a more hemispheric and zonally symmetric mode, which they identified with the Arctic Oscillation (AO + , AO − ). They found that these four regimes were in good agreement with previous results ( Kimoto and Ghil 1993a , b ; Michelangeli et al. 1995 ; Corti et al. 1997 ; Smyth et al. 1999 ). By studying the Markov chain of transitions between

Full access