Recent research suggests that both tropical ocean warming and
stratospheric temperature anomalies due to ozone depletion have led to a
poleward displacement of the midand high-latitude circulation of the Southern
Hemisphere over the past century. In this study, we attempt to distinguish the
influences of ocean warming and stratospheric cooling trends on seasonal
changes of both the zonally symmetric and asymmetric components of the southern
hemisphere circulation. Our analysis makes use of three data sets-the ERA40
reanalysis and results from two different runs of the GFDL global atmosphere
and land model (AM2.1) for the period 1870 to 2004. A regression analysis was
applied to two variables in each of the three data sets-the zonal component of
the surface wind U(10 m)
and the height at 300hPa—to determine their correlation with zonally
averaged polar stratospheric temperatures (T_polar—at 150hPa, averaged
over a band from 70S - 80S) and low-level equatorial temperatures (T_equator—at 850
hPa averaged over a band at 5S-5N). Our analysis shows that the zonally symmetric surface winds have a
considerably enhanced intensity in high latitudes of the
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