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SUMMARY:Turbulent transport and mixing of oceanic sea salt aerosol over th
 e Indian sub-continent: Cloud microphysical and geo-engineering implicatio
 ns - Prof Dr. S. Ghosh\, School of Mechanical Engineering\, Vellore Instit
 ute of Technology\, India
DTSTART:20170207T140000Z
DTEND:20170207T150000Z
UID:TALK70329@talks.cam.ac.uk
CONTACT:Dr Alexandra Weiss
DESCRIPTION:This study explores dynamical and microphysical development of
  clouds over the Bay of Bengal\nincluding days associated with cyclonic st
 orms (Cylone Pahilin\, Oct 2013). The vertical transport\nof sea spray to 
 cloud bases is first quantified‐from Landsat (L8) measurements launched 
 a few\nmonths prior to Phailin which whipped up strong winds producing spr
 ay droplets\, mostly in the\ncoarse mode\, at the crest of ocean waves. On
  calmer days one observed an additional fine\nmode. These sea salt aerosol
  distributions were then incorporated into a chemical parcel model\nyieldi
 ng realistic cloud droplet spectra which were grown to form much larger ra
 in drops\nthrough a process of stochastic coalescence.\n\nThe second part 
 of the study focuses on the effect of millimeter scale vortices obtained d
 uring\nboth stormy as well non‐stormy days on the quantification of rain
  rates.   In essence\, rescaled\nsettling of the small inertial particles 
 (mainly the film mode drops) is obtained as they are\n‘centrifuged’ ou
 t of vortices and eddies in turbulence. This process enhances the average\
 nsedimentation rate of particles lying below a critical radius (~ 20 micro
 ns) by about 80% strongly\nimpacting rain rates. Whist earlier studies hav
 e shown that multi‐component mixtures perturb\nthe Aerosol‐Cloud Dropl
 et relationships over certain regimes\; this first study shows that when\n
 multiple aerosol modes are present within convective clouds\, ano ther add
 ed perturbing effect‐\nthe enhanced settling rates from the centrifuging
  action of the micro‐scale eddies increases\nprecipitation rates over th
 e Bay of Bengal.  \n\n Wider implications are discussed including recent r
 esearch on cloud seeding (enhancement of precipitation) and the geo‐engi
 neering modulation of cyclonic storms through sea water injection mechanis
 ms (dissipation of rainfall over oceans prior to landfall).\n
LOCATION:British Antarctic Survey\, Room 187
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