Latent Heating Is Required for Firestorm Plumes to Reach the Stratosphere
Abstract
City-wide firestorms produce extreme convective plumes that loft soot into the atmosphere. If emplaced in the stratosphere, soot has long-lasting impacts on global climate. Given the extreme sensible heating from the fire, the importance of additional heating from condensation is unclear and a subject of debate. Analytic plume calculations presented here establish that an idealized dry plume requires a temperature anomaly of at least 60 K at the top of the boundary-layer to remain buoyant up to the cold-point tropopause. Direct numerical and large-eddy simulations indicate that dry firestorm plumes possess temperature anomalies that are less than the requirements for stratospheric ascent by a factor of two or more. In contrast, moist firestorm plumes are shown to reach the stratosphere by tapping into the abundant latent heat present in a moist environment. Latent heating is found to be essential to plume rise, raising doubts about the applicability of past work that neglected moisture.
- Publication:
-
Journal of Geophysical Research (Atmospheres)
- Pub Date:
- September 2022
- DOI:
- 10.1029/2022JD036667
- Bibcode:
- 2022JGRD..12736667T