Biomass burning (BB) particles, a major component of smoke from increasingly frequent and intense wildfires, play a significant role in radiative forcing and climate change. Strong convective events, such as intense summer storms, can rapidly transport BB and other tropospheric particles potentially into the upper troposphere and lower stratosphere (UTLS).

As part of the NASA Earth Venture Suborbital research project Dynamics and Chemistry of the Summer Stratosphere (DCOTSS), we developed a new airborne single particle mass spectrometer—Particle Analysis by Laser Mass Spectrometry – Next Generation (PALMS-NG). This instrument was deployed aboard the ER-2 high-altitude aircraft to characterize aerosol particles in the UTLS. In regions influenced by deep convection, we observed that carbonaceous-sulfate (CS) particles of tropospheric origin dominated the particle population (~90% number fraction) within a 4 km-layer above the tropopause. Notably, ~ 43% of these CS particles were identified as originating from biomass burning.

We propose that this 4 km-layer represents a convectively influenced stratospheric layer (CISL)—a feature not previously described in the literature but potentially significant for atmospheric chemistry and climate feedback. Further, we observed evidence of internal mixing between intruded tropospheric particles and background stratospheric components. Online and offline measurements revealed substantial chemical complexity, suggesting active perturbation within the lower stratosphere.

This study highlights a growing impact of biomass burning and convection on the stratospheric aerosol layer—an influence that is likely to intensify in the future. Continued research is needed to elucidate the underlying mechanisms and improve modeling of these processes.

In this talk, I will first introduce the PALMS-NG instrument, then present key findings on BB particles in the stratosphere from DCOTSS. I will also present preliminary results from the AEROMMA aircraft mission, which focuses on tropospheric composition.