Observed temperature structure of the atmosphere above Syowa Station, Antarctica (69°S, 39°E)

Abstract

By combining balloonsonde and Na/Rayleigh temperature lidar observations made at Syowa Station (69°S, 39°E) during 2000 and 2001 (a total of 176 observations, 5.9 observations per week), the winter temperature structure from 0 to 110 km is characterized from March to October. The data are also compared with the temperature model of South Pole from Pan and Gardner [2003] which was derived from observations made during the same period as the measurements at Syowa. Although Syowa and South Pole are separated more than ∼2300 km, the temperature structure is quite similar through the year below 30 km. The annual temperature amplitude at Syowa is about 6–7 K smaller than the South Pole data because of the difference in seasonal solar flux variations between the two sites. In spring when the polar vortex weakens and dissipates, the stratospheric temperatures at Syowa increase rapidly as a result of the inflow of warmer air from lower latitudes. In the mesosphere the annual temperature amplitude is anticorrelated with the solar heating because of the strong adiabatic heating and cooling effects associated with the meridional circulation system. The annual temperature amplitude at Syowa is ∼5 K smaller than at South Pole, which is consistent with the smaller adiabatic heating and cooling expected at lower latitudes. The semiannual amplitude at Syowa is 5–7 K larger than at South Pole between 30 and 60 km, and it is 15 K smaller than at South Pole between 80 and 100 km.