HR: 16:15h
AN: A54B-02    [Abstracts]
TI: Convective transport over the Tibetan Plateau - A short-circuit of water vapor and pollution to the global stratosphere
AU: * Fu, R
EM: fu@eas.gatech.edu
AF: Georgia Institute of Technology, 311 Ferst Dr., Atlanta, GA 30332-0340 United States
AU: Hu, Y
EM: yuanlong.hu@eas.gatech.edu
AF: Georgia Institute of Technology, 311 Ferst Dr., Atlanta, GA 30332-0340 United States
AU: Chen, M
EM: mchen@eas.gatech.edu
AF: Georgia Institute of Technology, 311 Ferst Dr., Atlanta, GA 30332-0340 United States
AU: Jiang, J H
EM: Jonathan.H.Jiang@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, ca 91109 United States
AU: Filipiak, M
EM: mjf@met.ed.ac.uk
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, ca 91109 United States
AU: Read, W
EM: bill@mls.jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, ca 91109 United States
AU: Waters, J W
EM: joe@mls.jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, ca 91109 United States
AB: Using measurements from the newly available Aura Microwave Limb Sounder (MLS) along with Aqua and TRMM satellites of the NASA Earth Observing System, we have observed that summer convection over the Tibetan Plateau and its south slope tend to cause greater instantaneous hydration and increase of CO in the tropopause layer (TL) and lower stratosphere (LS) compared to that over the South Asian Monsoon region. This can be explained by observed stronger convective updraft in the upper troposphere, lower relative humidity in the ambient tropopause layer, and possibly more smaller ice particles in the convectively generated cirrus/anvils and over the Tibetan Plateau. Convection over the monsoon region is more extensive, but its instantaneous transport of water vapor and pollutants to the TL appears to be less. This result, along with estimated diabatic cross-tropopause transport, suggests that summer convection over the Tibetan Plateau tends to more frequently `break-through" to the TL, providing episodes of fast, diabatic driven cross-tropopause transport of water vapor and pollutants. In addition, meridional isentropic transport is also more active over the Tibetan Plateau than over the monsoon region. It also contributes to the stronger cross-tropopause transport of water vapor and CO over the Tibetan Plateau. These fast transport processes could short-circuit the otherwise slower mixing of the water vapor and CO into the LS and dehydration by the cold temperatures in the tropical TL occurring mostly over the monsoon region. Over the monsoon region, convective/cirrus cloud effective radii appear to decrease with high CO. But over the Tibetan Plateau, the changes of ice particle sizes appear to be dominated by the strength of convection, instead of CO, presumably because of low concentration of pollution aerosols. These results imply that the stratospheric atmosphere composition would be especially sensitive to the change of convection and increases of pollution over the Tibetan Plateau, including pollution transported from the South Asian Monsoon region.
DE: 0320 Cloud physics and chemistry
DE: 0322 Constituent sources and sinks
DE: 0429 Climate dynamics (1620)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005