Pyrocumulonimbus (PyroCb) Clouds

pyrocb_thumb Pyrocumulonimbus (PyroCb) clouds are thunderstorms that have been created by or augmented by wildfires. These towering thunderstorms grow as a direct result of very strong convection within large or intense fires. Because these clouds grow within smoke plumes, the optical properties and cloud dynamics of pyroCbs differ from traditional meteorological cumulonimbus (Cb) clouds, making them unique. In extreme cases, pyroCbs can inject huge amounts of smoke and other biomass emissions into the lower stratosphere, about 40,000 feet above the ground. This injection of smoke into the stratosphere can have long-term effects on climate and it has been hypothesized that pyroCbs are part of the theoretical "nuclear winter" scenario. This, combined with strong evidence suggesting that pyroCbs occur much more frequently than previously thought, largely due to global and regional warming trends, gives pyroCbs real scientific importance. Significant progress has been made in recent years in pyroCb research, but these phenomena and their impacts on overall climate remain poorly understood.

CPI scientists at the Naval Research Laboratory (NRL) are working closely with NRL researchers to better understand the evolution, lifetime, dissipation, and dynamics of pyroCbs as well as the frequency of occurrence of these events and their effects on climate and society. As part of this effort, CPI scientists are developing methods to identify, catalog, and characterize pyroCbs in more than 30 years of Advanced Very High Resolution Radiometer (AVHRR) and Geostationary Operational Environmental Satellite (GOES) data. With CPI experience and know-how, NRL has the tools to build a more complete climatology of pyroCbs and the resources to do more quantitative and statistical analyses of these events.

A pyrocumulonimbus storm combines smoke and fire with the features of a violent thunderstorm. Pollutants from these storms are funneled into the stratosphere (Credit: Naval Research Laboratory/Mike Fromm).