HR: 15:10h
AN: A43D-07 INVITED     [Abstracts]
TI: Smoke From a Distant Fire: Stratospheric Plumes in the SAM/SAGE/POAM and TOMS Era
AU: * Fromm, M D
EM: mike.fromm@nrl.navy.mil
AF: Computational Physics, Inc., 8001 Braddock Rd. Suite 210, Springfield, VA 22151 United States
AU: Servranckx, R
EM: Rene.Servranckx@ec.gc.ca
AF: Canadian Meteorological Centre, 2121, North Service Road Trans-Canada Highway, Dorval, Que H9P 1J3 Canada
AU: Bevilacqua, R M
EM: bevilacqua@nrl.navy.mil
AF: Naval Research Lab, 4555 Overlook Ave., S.W., Washington, DC 20375 United States
AU: Shettle, E P
EM: shettle@nrl.navy.mil
AF: Naval Research Lab, 4555 Overlook Ave., S.W., Washington, DC 20375 United States
AU: Alfred, J
EM: alfred@cpi.com
AF: Computational Physics, Inc., 8001 Braddock Rd. Suite 210, Springfield, VA 22151 United States
AB: In the boreal summer of 1998, the solar occultation instruments POAM III and SAGE II, along with the Earth-Probe TOMS, captured a remarkable phenomenon that until then had not been discovered: eruptive convective transport of forest fire smoke into the stratosphere. The effect on the stratosphere was a five-fold increase in zonal-average aerosol optical depth and a multi-month decay period. These same three instruments were the main players in characterizing yet another pyro-convective event in the boreal summer of 2001. On that occasion the aerosol layers attributable to the eruption reached to 18 km (potential temperature = 458 K), fully 9 km above the tropopause. Since then there have been more observations of stratospheric forest fire emissions, remotely and in situ, in other years and in the southern hemisphere as well. The discovery of extreme pyro-convection has shone a light on the strengths of high vertical resolution solar occultation instruments in their important monitoring of the stratosphere and the upper troposphere. It has also revealed unrealized potential in TOMS aerosol index archive, especially the newly released version 8 product. Moreover, the discovery of these so-called pyrocumulonimbus ("pyroCb" for short) has opened up avenues for new discoveries of past events in the 25-year TOMS and solar occultation record and a new interpretation of others. This report is a preliminary survey of the 1979-present satellite record of pyroCb events. We explore the invaluable quarter-century record of aerosol measurements made by SAM II, SAGE I-III, POAM II and III, and Nimbus-7 and Earth-Probe TOMS. In that time we find that the pyroCb effect on the lower stratosphere has been surprisingly substantial. We combine the TOMS aerosol index data, which can be used to unambiguously isolate dense upper troposphere-lower stratosphere smoke plumes, with aerosol extinction measurements from the solar occultation instruments in a way that clearly distinguishes the pyroCb events from volcanic eruptions. In so doing, we find that the pyroCb phenomenon had a repeated impact on the stratospheric aerosol burden in both boreal and austral hemispheres. We also show that the historical record contains reports of mystery clouds and volcanically-attributed aerosols that owe their existence to the pyroCb. In this era, more than 25 likely pyroCb eruptions can be identified. We will present the historical findings in both a temporal and spatial context, and highlight selected case studies.
DE: 3362 Stratosphere/troposphere interactions
DE: 3314 Convective processes
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0322 Constituent sources and sinks
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting