Rayleigh lidar observation of a warm stratopause over a tropical site, Gadanki (13.5° N; 79.2° E)

[摘要] The first Rayleigh lidar observation of a stratopause warming over atropical 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 occurin the stratopause region (~45km). The magnitude of the warming wasfound to be ~18K with respect to the winter-mean temperature profilederived from the lidar data collected over March 1998 to July 2001. Theevent observed by the lidar has also been seen in data from the HalogenOccultation Experiment (HALOE) on board the UARS satellite. The zonal-meantemperature at 80° N and the zonal-mean zonal wind at 60° N from theNational Centre for Environmental Prediction (NCEP) reanalysis and theEuropean Centre for Medium-Range Weather Forecasts (ECMWF) analysis indicatethat a major warming episode took place in the northern polar hemisphere aweek before the day of the observation over Gadanki. Eliassen-Palm (E-P)flux calculations from ECMWF analysis show evidence of propagation ofplanetary-wave activity from high and mid- to low latitudes subsequent tothe major warming episode over the pole. Our results support the view thatthe most likely source mechanism for the observed stratopause warming is theincrease in planetary-wave activity.

[学科分类] 大气科学