Dear All,
Next week (Nov 21, at 1:15 pm), we will host prof. Wojciech Grabowski
(NCAR / Univ. Warsaw) for the AGH Environmental Physics Group seminar.
The talk will take place in lecture hall C ("pink"), building D-10, 3rd
floor (address: Reymonta 19).
Title:
Growth of Cloud Droplets in a Turbulent Environment
Abstract:
Formation of precipitation in warm (ice-free) clouds involves both
diffusional and collisional growth of cloud droplets. For both, cloud
turbulence has been argued to play an important role. In this talk, I
will review recent research in this area focusing on droplet
diffusional growth in adiabatic (i.e., undiluted) cloud volumes. The
focus on such regions is justified by observations and numerical
modeling that show rain and drizzle formation typically taking place
in undiluted and weakly diluted cloud volumes. At the same time,
however, in-situ aircraft observations show that droplet spectra in
such regions are often significantly wider than predicted by a simple
adiabatic parcel ascent from the cloud base. Droplet spectral width is
important for the onset of droplet gravitational collisions as well as
for the transfer of solar radiation through clouds. The problem of
spectral broadening due to cloud turbulence attracted significant
attention of cloud physics and turbulence communities over the last
couple decades. Theory and numerical simulations using idealized
frameworks of stochastic models, direct numerical simulation (DNS),
and scaled-up DNS have all been used to explain spectral broadening
observed in natural clouds. Simple concepts related to the impact of
turbulence on the diffusional growth of cloud droplets together with
results of numerical simulations will be presented.
Speaker:
Prof. Wojciech W. Grabowski
National Center for Atmospheric Research (NCAR), Boulder, CO, USA
Institute of Geophysics, Faculty of Physics, University of Warsaw
https://scholar.google.com/citations?user=WVjmW3wAAAAJ
ZFŚ seminar site & mailing list: https://zfs.agh.edu.pl/en/seminars
Best regards,
Sylwester Arabas
--
Environmental Physics Group, AGH University of Kraków, Poland
sylwester.arabas(a)agh.edu.pl | +48502254779 | https://zfs.agh.edu.pl/
