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SUMMARY:The Role of New Particle Formation in the Remote Atmosphere: Impro
 ving Our Understanding Through Pole-to-pole in-situ Measurements From the 
 Nasa Atmospheric Tomography Mission - Christina Williamson\, University of
  Colorado
DTSTART:20190910T150000Z
DTEND:20190910T160000Z
UID:TALK129190@talks.cam.ac.uk
CONTACT:Dr Hua Lu
DESCRIPTION:Cloud modifications due to aerosol are still the largest uncer
 tainty on total anthropogenic radiative forcing in global climate models. 
 A large part of this uncertainty is related to the number and spatial dist
 ribution of cloud condensation nuclei (CCN) in the global atmosphere. Aero
 sol from new particle formation (NPF) may account for more than 50% of CCN
  in global low-level clouds\, yet the processes that form\, grow and remov
 e these particles are under-constrained. This is particularly true in remo
 te regions\, where aerosol from NPF are more likely to influence cloud pro
 perties and thus global radiative balance.\n\nBetween 2016 and 2018 we fle
 w a substantial aerosol payload over the remote Pacific and Atlantic ocean
 s (86S - 83N) on the NASA Atmospheric Tomography Mission (ATom). The fligh
 ts were conducted once in each of the four seasons\, with constant profili
 ng between 0.2 and 12 km altitude. We measured aerosol size distributions 
 from 3 nm to 930 m in diameter\, as well as single particle and bulk ae
 rosol chemical composition.\n\nWe present analysis of the role of NPF in t
 he remote atmosphere\, including the location\, frequency and seasonality 
 of NPF occurring in the free troposphere and boundary layer. In areas wher
 e our measurements show a clear link between NPF and production of CCN\, w
 e compare our observations to global chemistry-climate models to asses mod
 el skill in representing these aerosol and their effect on global radiativ
 e balance.
LOCATION:British Antarctic Survey\, Seminar Room 187
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