Rayleigh lidar observation of a warm stratopause over a tropical site, Gadanki (13.5° N; 79.2° E) V. Sivakumar1, B. Morel1, H. Bencherif1, J. L. Baray1,2, S. Baldy1, A. Hauchecorne3, and P. B. Rao4 1Laboratoire de Physique de l’Atmosphère CNRS–UMR 8105, Université de La Réunion, 15 Av. René Cassin, BP 7151, 97715 Saint-Denis Messag. Cedex 9, La Réunion, France 2Institut Pierre Simon Laplace (IPSL), Observatoire de Physique de l’Atmosphère de la Réunion (OPAR), La Réunion, France 3Service d’Aéronomie CNRS-UMR 7620, France 4National Remote Sensing Agency, Bala Nagar, Hyderabad – 500 037, India
Abstract. The first Rayleigh lidar observation of a stratopause warming over a
tropical site, Gadanki (13.5° N; 79.2° E), is presented in this paper.
The warming event was observed on 22-23 February 2001, and found to occur
in the stratopause region (~45km). The magnitude of the warming was
found to be ~18K with respect to the winter-mean temperature profile
derived from the lidar data collected over March 1998 to July 2001. The
event observed by the lidar has also been seen in data from the Halogen
Occultation Experiment (HALOE) on board the UARS satellite. The zonal-mean
temperature at 80° N and the zonal-mean zonal wind at 60° N from the
National Centre for Environmental Prediction (NCEP) reanalysis and the
European Centre for Medium-Range Weather Forecasts (ECMWF) analysis indicate
that a major warming episode took place in the northern polar hemisphere a
week before the day of the observation over Gadanki. Eliassen-Palm (E-P)
flux calculations from ECMWF analysis show evidence of propagation of
planetary-wave activity from high and mid- to low latitudes subsequent to
the major warming episode over the pole. Our results support the view that
the most likely source mechanism for the observed stratopause warming is the
increase in planetary-wave activity.
Citation: Sivakumar, V., Morel, B., Bencherif, H., Baray, J. L., Baldy, S., Hauchecorne, A., and Rao, P. B.: Rayleigh lidar observation of a warm stratopause over a tropical site, Gadanki (13.5° N; 79.2° E), Atmos. Chem. Phys., 4, 1989-1996, doi:10.5194/acp-4-1989-2004, 2004.