Climate of the polar realms - The Global Climate System: Patterns, Processes, and Teleconnections - page 148

Table 5.2 Some potential teleconnections between El Ni˜o events and
Antarctic climate (after Bromwich and Parrish 1998 ; Turner 2004 ). Links are
highly variable and inconsistent

Antarctic climate parameter Comments

Increased surface winds and
colder surface temperatures

Depends on year grouping considered;
irregular impacts; time lags

Polar Front Jet weaker PFJ stronger during La Ni ˜a

Geopotential heights higher Geopotential heights lower during LaNi ˜a

Weaker circumpolar westerlies Modulations not the same between events

Positive height anomalies over
Amundsen-Bellingshousen
Sea area

Strongest signal, but considerable
variability in occurrence (opposite
during La Ni ˜a)

Diminished number of cyclones
in CPT
Amplified seasonal cycle creates
more meso-cyclones

Shifts in locations

MSLP anomalies change from
positive to negative across SOI
minimum

Occurs generally across the continent

Variations in the circumpolar
wave pattern

Dynamics not well understood

Precipitation lower Irregular/inconsistent impacts; strongest

in West Antarctica

Higher Ross Sea SST 2-4 month lag

Reduced Ross Sea sea ice area Limited data

wind regime. Wind speeds at Neumayer can exceed 50m s 1 , but at Halley Bay,
which is more sheltered, winds rarely exceed 40m s 1 .
King and Turner ( 1997 ) provide an extensive description of the range of
mesoscale cyclones that can develop and die within the CPT, at a smaller spatial
scale than the synoptic lows. These systems can create a variety of short-term
severe weather conditions, adding to the extreme complexity of storms and their
interactions along the Antarctic coast.

5.6 Antarctic climate and ENSO
An excellent review by Turner ( 2004 ) provides a detailed evaluation of the
potential impacts of ENSO (see Section 2.8 ) on Antarctic climate patterns.
Table 5.2 summarizes the major relationships, but also emphasizes that there
is a strong lack of consistency and stability over time. Other reasons for climatic
variations, such as the AAO, are therefore more important. ENSO signals are