Tr. Parish et al., FORCING OF THE AUSTRAL AUTUMN SURFACE PRESSURE CHANGE OVER THE ANTARCTIC CONTINENT, Journal of the atmospheric sciences, 54(11), 1997, pp. 1410-1422
Pronounced seasonal variations in the surface pressure field are prese
nt over the Antarctic continent. Surface pressures over the ice sheet
decrease during the austral autumn period January-April and increase d
uring the austral springtime months September-December. The largest ch
anges are found over the highest portions of the Antarctic ice sheets
where seasonal surface pressure changes of up to 20 hPa are common. Th
e outstanding feature of these surface pressure changes is that typica
lly the isallobaric contours closely follow the Antarctic orography du
ring both transition periods, suggesting a strong seasonal diabatic ad
justment within the lower troposphere. During austral autumn, the pron
ounced cooling of the lower atmosphere adjacent to the ice sheets lead
s to an enhancement of the Antarctic katabatic wind regime and hence t
he lower branch of the mean meridional circulation over the high south
ern latitudes. The mass transport provided by these drainage flows is
proposed as the mechanism behind the autumn pressure falls. Numerical
simulations of the evolution of the Antarctic katabatic wind regime in
dicate that the radiative cooling of the sloping ice fields and attend
ant mass transport result in a modification of the temperature and pre
ssure fields in the lower troposphere similar to what is seen during t
he early austral autumn period.