Speaker: Arman Pouyaei (Princeton)
Title:"Interactive Fire Emission and Injection in GFDL's Earth System Model

Abstract:
Wildfires inject aerosols and trace gases into the atmosphere at varying altitudes, modifying long-range transport, which impacts Earth’s radiation budget, atmospheric circulation, and cloud formation. To better represent the interaction of atmospheric tracers from wildfires and climate, we integrated a smoke plume height parametrization into GFDL’s aerosol-only atmospheric model (AM.0) and full-chemistry model (AM4.1). We also coupled interactive fire emission fluxes and injections from the land component (LM4.1) to the atmosphere. Using historical simulations with prescribed fire emissions, our results show that the dynamic injection of biomass burning emissions alters net radiative fluxes at the top of the atmosphere regionally by ±1.5 W/m² and reduces them globally by -0.38 W/m² at the surface compared to a baseline with no fire emissions. The associated temperature gradient anomalies from absorbing aerosols affect atmospheric stability and circulation patterns. Furthermore, analysis of biomass burning emissions' variability reveals that they are one of the contributors to ENSO-driven variability in tropospheric ozone's instantaneous radiative forcing, alongside other drivers such as lightning-NOx emissions and stratospheric-tropospheric ozone exchange. Additionally, preliminary results from interactive fire emissions within the coupled LM4.1/AM4.1 model show global emission fluxes comparable to observed values. Future work will focus on using the developed interactive fire emission in the Earth System Model to project changes in atmospheric absorption and cloud properties, and their feedbacks under future climate scenarios.