Abstract:
Thunderstorm clouds may reach the lower stratosphere, affecting the exchange of greenhouse
gases between the troposphere and stratosphere. This region of the atmosphere is difficult to access
experimentally, and our knowledge of the processes taking place here is incomplete. We recently recorded
color video footage of thunderstorms over the Bay of Bengal from the International Space Station. The
observations show a multitude of blue, kilometer-scale, discharges at the cloud top layer at ~18 km altitude
and a pulsating blue discharge propagating into the stratosphere reaching ~40 km altitude. The emissions
are related to the so-called blue jets, blue starters, and possibly pixies. The observations are the first of their
kind and give a new perspective on the electrical activity at the top of tropical thunderstorms; further, they
underscore that thunderstorm discharges directly perturb the chemistry of the stratosphere with possible
implications for the Earth’s radiation balance.
