Signature of latitudinal coupling during a major sudden stratospheric warming in the tropics

A major sudden stratospheric warming (SSW) in lidar temperature is observed during late February, 2007 from a tropical station, Gadanki (13.5°N, 79.2°E). Latitudinal coupling through dynamical parameters during the warming period has been studied using ECMWF and NCEP reanalysis data, which has revealed appreciable alteration of the lower stratosphere in response with the abrupt forcing. Sufficient air mass transport from low to high latitude has been observed during the event which indicates possible heat transmission to fuel the heating at polar region. On starting from high latitude, enhanced planetary wave amplitude reaches at sufficiently low latitude during the event and reverts back hereafter. Gravity wave activity increases at later phase of the warming episode and continues for a couple of days at high latitude. A dynamical incitement occurs a couple of weeks preceding the SSW suspected to excite the event.

► Sudden stratospheric warming observed over a tropical site, Gadanki (13.5°N, 79.2°E). ► Significant air mass flows from low to high latitude believed to carry sufficient heat. ► Latitudinal movement of the planetary waves during the event is noteworthy. ► Gravity wave activity increases at later phase of the warming episode.