HR: 10:20h
AN: A22B-01 INVITED     [Abstracts]
TI: An Exploratory Study of the Impact of Pyro-cumulonimbus Injections of Aerosol on the Upper Troposphere and Lower Stratosphere Climate During Northern Hemisphere Summer
AU: * Rasch, P J
EM: pjr@ucar.edu
AF: National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307-3000 United States
AU: Fromm, M
EM: mike.fromm@nrl.navy.mil
AF: Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, DC 20375 United States
AU: Torres, O
EM: torres@qhearts.gsfc.nasa.gov
AF: Goddard Space Flight Center, Greenbelt Road, Greenbelt, MD 20771 United States
AU: Diner, D J
EM: djd@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AU: Kahn, R
EM: ralph.kahn@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AU: Martonchik, J
EM: jvm@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AB: The direct injection of forest fire smoke into the extratropical lower stratosphere by pyro-cumulonimbus (pyroCb) convection provides a dramatic example of a mechanism for rapid vertical transport of radiatively active material from the lower troposphere. This region is characterized by strong vertical stability, and most pathways for transport require slower moving trajectories of exchange along isentropes between the upper tropical troposphere and the lower stratosphere. Measurements from SAGE and POAM of very strong PyroCb events suggest that the aerosol can be injected as high as 6 km above the tropopause. Early analysis from MISR data have documented strongly absorbing aerosols at 12-14km from the Chisholm Fire of 2001. Analysis from TOMS indicates the aerosol plumes can have optical depths exceeding 1.0 at 360 nm, with single scattering albedos of 0.65 to 0.75. This absorption is significantly higher than the values reported for typical tropospheric biomass burning (AERONET) associated with smoldering phase fires. The extreme events described here provide one dramatic mechanism for occasional injection of aerosol into the stratosphere but there must certainly be less extreme events that also act as sources to this region. We will describe our preliminary findings about the role of PyroCb as a source for absorbing aerosol in the UTLS and its effect on the general circulation of the atmosphere as demonstrated in simulations using the Community Atmosphere Model.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere: composition and chemistry
DE: 1622 Earth system modeling (1225)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005