Middle atmosphere - lower atmosphere interactions

Middle atmosphere composition is affected by the troposphere by slow transport of anthropogenic and biogenic trace gases over the tropical tropopause, but also by fast transport in sporadic natural and man-made events: volcanic eruptions and strong wildfires. We investigate the impact of wildfires on the lower stratosphere using satellite data, see below.

Planetary and gravity waves accelerated in the lower atmosphere propagate into the middle atmosphere; their dissipation drives the meridional circulation of the stratosphere and mesosphere. On the other hand, the dynamical state of the middle atmosphere can have an impact on tropospheric weather regimes particularly during high-and midlatitude winters. The formation and impact of strong stratospheric polar vortices is investigated in the DFG-funded project ENRICH. 

Stratospheric impact of wildfires

Over the last years, the frequency and intensity of wildfires has dramatically increased. Severe wildfires can release big amounts of heat into the atmosphere, which provokes extreme thunderstorms named Pyrocumulonimbus (PyroCb). These storms, amplified by the combustion energy, can generate the uplift of smoke and other combustion products even into the stratosphere, where they interact with and contribute to the stratospheric aerosol layer. Recent studies argue that the effect of some wildfires on the radiation budget of the atmosphere is therefore comparable with the effect of moderate volcanic eruptions.

We apply a nadir/limb synergy approach for the detection of PyroCb events with stratospheric impact from satellite measurements.