HR: 09:30h
AN: A31B-07    [PDF]
TI: Warming of the Arctic Lower Stratosphere by Light Absorbing Particle
AU: * Baumgardner, D
EM: darrel@servidor.unam.mx
AF: Universidad Nacional Autonoma de Mexico, Centro de Ciencias de la Atm¢sfera - UNAM Universidad Nacional Aut¢noma de M‚xico Circuito Exterior s/n, Ciudad Universitaria, M‚xico City, DF 04510 Mexico
AU: Raga, G B
EM: raga@servidor.unam.mx
AF: Universidad Nacional Autonoma de Mexico, Centro de Ciencias de la Atm¢sfera - UNAM Universidad Nacional Aut¢noma de M‚xico Circuito Exterior s/n, Ciudad Universitaria, M‚xico City, DF 04510 Mexico
AU: Kok, G
EM: glkok@dropletmeasurement.com
AF: Droplet Measurement Technologies, 5710B Flatiron Parkway, Boulder, CO 80301 United States
AU: Anderson, B
EM: B.E.Anderson@LaRC.NASA.GOV
AF: NASA Langley Research Center, Mail Stop 483, Hampton, VA 23681-0001 United States
AB: Light absorption by particles such as soot and dust change the thermodynamic structure of the atmosphere and contribute to regional and global climate change. The lower stratosphere is particularly sensitive to the presence of light absorbing particles (LAP) since particles in this region can reside from months to years, in contrast to upper tropospheric lifetimes of days to weeks. The source of particles in the lower stratosphere may be aircraft, meteorites or transport from tropospheric sources. There is a serious deficiency of accurate and quantitative measurements of these particles that limits our understanding of the origin and lifetime of aerosols in this region of the atmosphere and how their presence alters radiative fluxes that lead to climate change. Here we present measurements in the Arctic lower stratosphere with a new, single particle soot photometer (SP2) that has detected black carbon (BC) mass concentrations of 20-1000 ng m$^{-3}$. These concentrations are 10-1000 times larger than those reported in previous experimental studies and are at least 30 times larger than predictions based on fuel consumption by commercial aircraft. The comparison of the measurements of BC with published 3D model predictions suggests that particles transported from the troposphere are the likely source of LAP in the Arctic lower stratosphere. Radiative transfer calculations that include the presence of a layer of LAP between 9 and 12 km, indicate an increase in the localised heating of this layer by approximately 25%.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting