Mie lidar and radiosonde observations at Gadanki (13.5°N, 79.2°E) during sudden stratospheric warming of 2009

►Persistent occurrence of cirrus clouds over Gadanki (13.5°N, 79.2°E) during 2009 stratwarm event. ►∼40% relative humidity at 11-13 km altitude and lower tropopause temperature over Gadanki. ►High potential vorticity intrudes from polar to tropics and causes deep tropical convection. ►Deep convection along with high humidity and low tropopause temperature may form cirrus clouds.