HR: 14:40h
AN: A33G-05 INVITED    [Abstracts]
TI: The Impact of Deep Convection on the Mid- and Upper Tropospheric Aerosol Size Distribution
AU: * Ekman, A M
EM: annica@misu.su.se
AF: Stockholm University, Department of Meteorology, Stockholm, 10691, Sweden
AU: Engstrom, A
EM: anderse@misu.su.se
AF: Stockholm University, Department of Meteorology, Stockholm, 10691, Sweden
AU: Krejci, R
EM: radek@misu.su.se
AF: Stockholm University, Department of Meteorology, Stockholm, 10691, Sweden
AU: Strom, J
EM: johan@itm.su.se
AF: Stockholm University, Department of Applied Environmental Science, Stockholm, 10691, Sweden
AU: Wang, C
EM: wangc@mit.edu
AF: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
AB: A cloud-resolving model is used in combination with observations of aerosol size distributions from the LBA- CLAIRE and INDOEX campaigns in order to better understand aerosol transport and processing within deep convective clouds. It is shown that deep convective clouds are an important source of accumulation mode aerosols (~>100 nm) to the mid-troposphere (altitudes between approximately 5 and 9 km). In this region, heterogeneous freezing results in strong mixing at the lateral boundaries of the cloud that in turn generates evaporation and re-suspension of aerosols to the air outside of the cloud. These aerosols are important for the lifetime and development of the convective cloud. For the upper tropospheric aerosol distribution, the study confirms that the outflow region is a source of small particles formed by nucleation. These aerosols grow into the Aitken mode (~>30 nm) and are together with direct transport from the boundary layer the main source of Aitken mode aerosols at this altitude. For the LBA-CLAIRE region, the model underestimates the observed nucleation and Aitken mode aerosol concentration. We discuss possible explanations to this discrepancy and also analyze the importance of using a correct mixing state of the aerosols when simulating aerosol transport within convective clouds.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0320 Cloud physics and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
DE: 3311 Clouds and aerosols
DE: 3314 Convective processes
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting