Large-scale planetary disturbances in stratospheric temperature at high-latitudes in the Southern Summer Hemisphere

Abstract

Abstract. The global structure and propagation of large-scale (periods >5 days) waves in the Southern Hemisphere summer (December 2006–February 2007) at 60° S–75° S latitude are examined using temperature data from GPS radio occultation measurements by COSMIC/FORMOSAT 3 satellite constellation from 10 to 40 km altitude. Spectral analysis has revealed eastward propagating planetary scale perturbations with wavenumbers 1 and 2 and periods of 10-, 16- and 23 days, zonally symmetric waves with the same periods and stationary waves with wavenumber 1 and 2. The presence of the zonally symmetric waves is interpreted as an indication of the coupling of the stationary and traveling waves. The results obtained show a very dynamically active Antarctic summer stratosphere. The novel aspect of the work is in the use of the GPS COSMIC data providing multiple local times each day, thus allowing large-scale wave analysis at high Southern latitudes and revealing planetary wave activity not normally observed in summer, but more consistent with late winter and spring conditions in the stratosphere.