HR: 14:10h
AN: A43E-03 INVITED    [Abstracts]
TI: Observations of Nighttime New Particle Formation in the Troposphere
AU: * Lee, S
EM: slee19@kent.edu
AF: Kent State Unversity, Dept Chemistry, Kent, 44242, United States
AU: Benson, D
EM: dbenson2@kent.edu
AF: Kent State Unversity, Dept Chemistry, Kent, 44242, United States
AU: Young, L
EM: lyoung8@kent.edu
AF: Kent State Unversity, Dept Chemistry, Kent, 44242, United States
AU: Kulmala, M
EM: kulmala@cc.helsinki.fi
AF: University of Helsinki, Department of Physical Sciences, Helsinki, 10000, Finland
AU: Suni, T
EM: tmsuni@mappi.helsinki.fi
AF: University of Helsinki, Department of Physical Sciences, Helsinki, 10000, Finland
AU: Junninen, h
EM: Heikki.Junninen@helsinki.fi
AF: University of Helsinki, Department of Physical Sciences, Helsinki, 10000, Finland
AU: Rogers, D
EM: dcrogers@ucar.edu
AF: NCAR, Earth Observing Laboratory, Broomfield, 80301, United States
AU: Campos, T
EM: campos@ucar.edu
AF: NCAR, Earth Observing Laboratory, Broomfield, 80301, United States
AU: Jensen, J
EM: jbj@ucar.edu
AF: NCAR, Earth Observing Laboratory, Broomfield, 80301, United States
AB: We present atmospheric and laboratory observations which indicate efficient new particle formation during the nighttime in the troposphere under low condensation sinks, in contrast to the current prevailing assumption that aerosol nucleation takes places only during the daytime and typically from sulfuric acid. High concentrations of ultrafine particles with diameters from 4 to 9 nm (up to 1,000 per cc) were measured from the three days of nighttime observations in the upper troposphere during the NSF/NCAR GV Progressive Science Missions. Long- term ground-based observations of charged and neutral clusters and aerosols made in Tumbarumba, Australia, also showed surprisingly high frequency of nighttime new particle formation (30 - 64 %) with low condensation sinks. Laboratory studies also indicated that nucleation takes place at low concentrations of sulfuric acid without photochemical processes in the absence of UV and OH. These observations show that nighttime nucleation processes are more important than previously understood. Nighttime nucleation can be significant for global aerosol load and cloud condensation nuclei productions and thus need to be included in global climate models.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting