The CONTANGO-FIRE mission will focus on three research topics.

Influence of Deep Convection over South America on the UTLS composition

It has been shown that convection plays a key role for the transport of short-lived organic compounds in combination with lightning NOx and photochemistry under low temperature conditions to form condensation nuclei in the UT. Biomass burning occurs, but activity is expected to be moderate during austral summer, providing the possibility to study vertical transport to the tropopause and redistribution of aerosol and its precursors also under pristine background conditions. The fate of the freshly formed particles, their potential to contribute to the lowermost stratospheric aerosol at the extratropical tropopause, as well as the dynamical mechanisms to transport these species across the tropopause into the LMS remains unclear.

In CONTANGO-FIRE we want to study the dynamical processes which may lead to transport and mixing of air masses across the tropopause associated with convection and the jets. We are especially interested in:

• the small-scale dynamical processes associated with convectively generatedgravity wave breaking at the tropopause
• the evolution of gas phase and aerosol air mass composition particularly freshly formed aerosol downwind the convective systems
• the role of transport and cross tropopause mixing at the jet stream.

Upper tropospheric new particle formation and gas phase oxidation

HALO is currently the only aircraft platform able to determine the direct nucleation precursors and to observe the temporal evolution of the nucleation events. With the unique set of instrumentation proposed for the CONTANGO-FIRE mission, the unambiguous identification of the precursor chemistry of the UT new particle formation processes is possible. So far, these processes have been studied in a few research flights during the two tropical missions CAFEBrazil and CAFE-Pacific, but New Particle Formation (NPF) in midlatitude regions has not been studied. 

Influence of Wildfire emissions on atmospheric chemistry, clouds and climate

Although wildfires are most common during the dry season, climate warming and El Niño have caused rising temperatures, prolonged droughts, and disrupted rainfall patterns in the Andes region, leading to notable burning events outside typical dry seasons.  Deep convective clouds develop daily along the eastern slopes of the Andes during the austral summer. These convective systems may enable the transport of fire plumes to high altitudes, potentially even penetrating the tropopause into the stratosphere. Through the CONTANGO-FIRE mission based in Argentina, we aim to study biomass burning in the Andes region and central South America under the conditions of climate-warming-induced prolonged and intensified droughts and high temperatures. Additionally, we will explore its interactions with deep convection and its effects on new particle formation at high altitudes.