Abstract:

Based on the 33rd Antarctica expedition radiosonde data collected at the Great Wall and Feri stations, the vertical structure characteristics of the atmosphere in the summer and the variations of tropopause height under different synoptic systems around the Great Wall station were analyzed with reanalysis data and radiosonde data from eight World Meteorological Orgation stations. The results show that the height of the lapse rate tropopause at the Great Wall station was 8 500 m and the height of cold point tropopause was 9 000 m. The tropopause temperature was approximately –50℃ and the mean wind velocity of the tropopause was 21 m·s–1. The mid-troposphere lapse rate was –6.34℃·km–1. The height of the boundary layer was 600 m and its mean wind velocity was 10 m·s–1. The tropopause height and vertical lapse rate at the Great Wall station varied considerably under different synoptic systems. When the east side of the Antarctic Peninsula is controlled by a cyclone or polar anticyclone, the Antarctic Great Wall station is affected by the cold dry southerly airstream. The development of convection is inhibited, leading to a low tropopause height and small vertical atmospheric lapse rate; the opposite is also true. Comparison with the WMO station data found that the tropopause height of the southeast continent is higher than that of the southwest. The height of the South Pole is the lowest, which may be closely related to the development source of a circumpolar cyclone. For the variation trend of the tropopause on a large scale, the reanalysis data (NCEP and ERA-interim) are reliable. However, on a synoptic scale, the NCEP data has a better performance than ERA-interim data compared with the radiosonde data results.

Key words: Antarctic vertical atmospheric structure, tropopause height, boundary layer structure, cyclone influence on the tropopause