[Grad-postdoc-assn] Thompson Lecture Series w/ Dr. Ulrike Lohmann, Dec 9-12 -- Sign up for meetings, potluck, and Research Aviation Facility (RAF) tour!

[Colin Zarzycki]

Hi NCAR Postdocs,

The Thompson Lecture Series (TLS) is coming up on December 9-12th featuring
Dr. Ulrike Lohmann. You can read more about the TLS and Dr. Lohmann here
<https://wiki.ucar.edu/display/aspthompson08/Thompson+Lecture+December+2014>.
The schedule of events is here
<https://wiki.ucar.edu/display/aspthompson08/Schedule+Ulrike+Lohmann>.
Abstracts for Dr. Lohmann's two lectures are added below and also on the
website.

In addition to lectures, one of the primary goals of the TLS is to provide
a venue for postdoc / guest meetings and networking.  There will be lots of
opportunities for formal meetings and socializing!

Wednesday, Dec 10
Lunch with postdocs - 12:30-2pm, ML Cafeteria
5 slots for postdoc meetings
<https://wiki.ucar.edu/display/aspthompson08/Individual+meetings+with+Dr.+Lohmann>
- 2-5pm, ML Chapman Room
Potluck dinner with postdocs and their families
<https://wiki.ucar.edu/pages/viewpage.action?pageId=295012873> - 5:30pm, ML
Damon Room

Thursdays, Dec 11
3 slots for postdoc meetings
<https://wiki.ucar.edu/display/aspthompson08/Individual+meetings+with+Dr.+Lohmann>
- 9-10:30am, FL2 1003
Lunch with postdocs - 12:30-2pm, FL Cafeteria
5 slots for postdoc meetings
<https://wiki.ucar.edu/display/aspthompson08/Individual+meetings+with+Dr.+Lohmann>
- 2-5pm, FL2 1003

Friday, Dec 12
Breakfast and science discussion with postdocs - 9-10:30am, Research
Aviation Facility (RAF) Conference Room
Tour of RAF facilities
<https://wiki.ucar.edu/display/aspthompson08/Schedule+Ulrike+Lohmann>** -
10:30-11:30am, RAF Hanger

You can sign up for individual meetings, the potluck dinner, and the RAF
tour at the wiki links provided above (click edit in the upper right corner
of the page). Don't be afraid to sign up just because you think your
science interests are different than the speaker. You may find that they
have a breadth of interests and can also offer you interesting insights on
your career development.

***Special notes for RAF tour*: Sign up right on the calendar at the link
above. On the calendar, please include your name AND citizenship. This is
required for ITAR approval. In addition, if you would like to carpool
from/to either Mesa Lab or Foothills Lab (leaving at 8:30 AM), please add
as well. Also note, we are asked to wear closed-toed shoes to the tour (no
sandals, etc.).

We will send out a couple more reminders as we get closer, but please go
ahead and fill up those slots!  Please do note hesitate to send an email if
you have any questions.

Cheers,

Colin

-----

General seminar, * Wednesday December 10, 2014, 11am - noon, Mesa Lab main
seminar room*
*"Grand challenges in understanding clouds: from ice crystal formation to
their influence on climate”*

Abstract: Clouds are not only fascinating to watch for their myriad of
shapes, but are also scientifically challenging because their formation
requires both knowledge about the large-scale meteorological environment as
well as knowledge about the details of cloud droplet and ice crystal
formation on the micro-scale. The ice phase in cloud remains enigmatic
because ice crystal number concentrations can exceed the number
concentrations of those aerosol particles acting as centers for ice
crystals (so-called ice nuclei) by orders of magnitude. To date,
measurement devices for ice nuclei are rare and custom-made. In this work,
I present the significant progress that has been made in the ice nucleation
community in identifying which aerosol particles may act as ice nuclei and
why.
As pointed out in the fifth assessment report of the Intergovernmental
Panel on Climate Change, the radiative forcing due to aerosol-cloud
interactions remains the largest uncertainty of the anthropogenic forcings.
On the other hand, how clouds change in a warmer climate is the largest of
uncertainties in terms of the expected warming at a point of doubling of
carbon dioxide.

Scientific seminar,  *Thursday December 11, 2014, 11am - noon, Foothills
Lab large auditorium *
*"Observations and model simulations of orographic mixed-phase clouds at
mountain range site”*

Abstract: Aerosol-cloud interactions constitute the highest uncertainties
in radiation forcing estimates. Uncertainties due to the phase and
longevity of mixed-phase clouds (MPCs) influence the radiative balance and
the hydrological cycle. Due to Wegener-Bergeron-Findeisen-process (WBF)
which describes the glaciation of MPC due to the lower saturation vapor
pressure over ice than over water, the MPCs are mostly expected to be
short-lived. In contrast, in-situ measurements have shown that MPCs can
persist over longer time.

We present measurements obtained at the high-altitude research station
Jungfraujoch (JFJ, 3580 m asl) in the Swiss Alps partly taken during the
CLoud-Aerosol Interaction Experiments (CLACE). During the winter season,
the JFJ has a high frequency of super-cooled clouds and is considered
representative for being in the free troposphere. In-situ measurements of
the microstructure of MPCs have been obtained with the digital imager
HOLIMO II, that delivers phase-resolved size distributions, concentrations,
and water contents. The data set of MPCs at JFJ shows that for northerly
wind cases partially-glaciated MPCs are more frequently observed than for
southerly wind cases. The higher frequency of these intermediate states of
MPCs at the JFJ suggests either higher updraft velocities, and therefore
higher supersaturations with respect to water, or the absence of
sufficiently high IN concentrations to quickly glaciate the MPC.

Because of the limitation of the in-situ information, i.e. point
measurements and missing measurements of vertical velocities at JFJ, the
mechanism of the long persistence of MPCs at JFJ cannot be fully
understood. Therefore, in addition to measurements we investigate the JFJ
region with a regional model study with a new version of the
non-hydrostatic model COSMO that includes the online coupled Aerosol
reactive trace gases model (ART) and the aerosol module M7. The combination
of kilometer-scale simulations with measurements allows to systematically
study the effect of vertical velocity and temperatures on MPCs at JFJ, the
synoptic conditions, origins of air masses and aerosol concentration.


-- 
Colin M. Zarzycki, ASP postdoctoral fellow
Atmospheric Modeling and Predictability
National Center for Atmospheric Research
http://www.colinzarzycki.com
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