Observation of stratosphere-troposphere exchange during a pre-monsoon thunderstorm activity over Kochi, India

A severe thunderstorm developed on May 18, 2017 over the Kochi (10.03 degrees N, 76.33 degrees E), a coastal region located in the southwest Peninsular India, with overshooting tops as high as 16 km. Observations made using stratosphere troposphere (ST) radar located at Kochi during May 17-19, 2017 show that strong convection reached the tropopause height during this event, and considerable mixing has happened. This paper describes the exchange between the stratosphere and troposphere during this thunderstorm event, a few days prior to the onset of Indian Summer Monsoon. The air near the vicinity of the tropopause was characterised by notably high concentrations of humidity and CO. A tongue of air with stratospheric characteristics lay below the tropopause, showing that extensive stratosphere-troposphere exchange had occurred. The effects of such a mechanism on atmospheric budgets of trace species in the stratosphere may alter the lower stratosphere's chemistry. Detailed estimates of the fluxes are also presented in the paper.