Worldwide Pyrocumulonimbus Inventory Reveals the Frequency, Variability, and Stratospheric Impact of Smoke-Infused Storms during 2013-2021

This study provides the first comprehensive inventory of all known pyrocumulonimbus (pyroCb) events observed worldwide (546 confirmed events) over the nine-year period 2013-2021. PyroCbs are a dangerous and severe type of fire weather, which present many hazards to firefighting efforts and communities along the wildland-urban interface. These unique storms also serve as a vertical transport pathway (large chimney) facilitating rapid injection of smoke into the upper troposphere and lower stratosphere (UTLS). This inventory provides insight into basic questions on inter-annual, seasonal, sub-daily, and regional variability of pyroCb, along with potential controlling factors. Development of this inventory has included detailed analysis of the distribution and variability of pyroCb smoke injection altitudes, quantitative estimation of the aerosol mass associated with each stratospheric plume, and examination of the impact of pyroCb activity on stratospheric aerosol loading worldwide. This pyroCb inventory provides the means to address a wide range of significant open questions about the nature, behavior, and impact of this phenomenon. Answers to these questions are critical for advancing pyroCb prediction capabilities to mitigate aviation hazards and aid firefighting efforts. This new multi-year inventory dataset also sets a foundation for an official Earth System Data Record that can be maintained into the future and extended back in time to identify longer-term trends in pyroCb activity and ensuing impacts on the climate system.