Antarctic polar descent and planetary wave activity observed in ISAMS CO from April to July 1992

D. R. Allen and N. Nakamura, Department of Geophysical Sciences, University of Chicago, Chicago, IL

J. L. Stanford, Department of Physics and Astronomy, Iowa State University, Ames, IA

M. A. Lopez-Valverde and M. Lopez-Puertas, Instituto de Astrofisica de Andalucia (CSIC), Granada, Spain

F. W. Taylor and J. J. Remedios, Department of Physics, Oxford University, Oxford, United Kingdom

Geophysical Review Letters, vol. 27, pp 665-668 (2000)


Antarctic polar descent and planetary wave activity in the upper stratosphere and lower mesosphere are observed in ISAMS CO data from April to July 1992. CO-derived mean April-to-May upper stratosphere descent rates of 15 K/day at 60 S and 20 K/day at 80 S are compared with descent rates from diabatic trajectory analyses. At 60 S there is excellent agreement, while at 80 S the trajectory-derived descent is significantly larger in early April. Zonal wavenumber 1 enhancement of CO is observed on 9 and 28 May, coincident with enhanced wave 1 in UKMO geopotential height. The 9 May event extends from 38 to 68 km and shows westward phase tilt with height, while the 28 May event extends from 40 to 50 km and shows virtually no phase tilt with height.