<div dir="ltr"><div>Hi NCAR Postdocs,</div><div><br></div><div>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 <a href="https://wiki.ucar.edu/display/aspthompson08/Thompson+Lecture+December+2014">here</a>. The schedule of events is <a href="https://wiki.ucar.edu/display/aspthompson08/Schedule+Ulrike+Lohmann">here</a>. Abstracts for Dr. Lohmann's two lectures are added below and also on the website.</div><div><br></div><div>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!</div><div><br></div><div>Wednesday, Dec 10</div><div>Lunch with postdocs - 12:30-2pm, ML Cafeteria</div><div><a href="https://wiki.ucar.edu/display/aspthompson08/Individual+meetings+with+Dr.+Lohmann">5 slots for postdoc meetings</a> - 2-5pm, ML Chapman Room</div><div><a href="https://wiki.ucar.edu/pages/viewpage.action?pageId=295012873">Potluck dinner with postdocs and their families</a> - 5:30pm, ML Damon Room</div><div><br></div><div>Thursdays, Dec 11</div><div><a href="https://wiki.ucar.edu/display/aspthompson08/Individual+meetings+with+Dr.+Lohmann">3 slots for postdoc meetings</a> - 9-10:30am, FL2 1003</div><div>Lunch with postdocs - 12:30-2pm, FL Cafeteria</div><div><a href="https://wiki.ucar.edu/display/aspthompson08/Individual+meetings+with+Dr.+Lohmann">5 slots for postdoc meetings</a> - 2-5pm, FL2 1003</div><div><br></div><div>Friday, Dec 12</div><div>Breakfast and science discussion with postdocs - 9-10:30am, Research Aviation Facility (RAF) Conference Room</div><div><a href="https://wiki.ucar.edu/display/aspthompson08/Schedule+Ulrike+Lohmann">Tour of RAF facilities</a>** - 10:30-11:30am, RAF Hanger</div><div><br></div><div>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.</div><div><br></div><div>**<i>Special notes for RAF tour</i>: 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.).</div><div><br></div><div>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.</div><div><br></div><div>Cheers,</div><div><br></div><div>Colin</div><div><br></div><div>-----</div><div><br></div><div><div>General seminar, <i> Wednesday December 10, 2014, 11am - noon, Mesa Lab main seminar room</i></div><div><b>"Grand challenges in understanding clouds: from ice crystal formation to their influence on climate”</b></div><div><br></div><div>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.</div><div>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.</div></div><div><br></div><div><div>Scientific seminar, <i>Thursday December 11, 2014, 11am - noon, Foothills Lab large auditorium </i></div><div><b>"Observations and model simulations of orographic mixed-phase clouds at mountain range site”</b></div><div><br></div><div>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.</div><div><br></div><div>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.</div><div><br></div><div>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.</div></div><br clear="all"><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><div dir="ltr" style="font-size:small;font-family:arial">Colin M. Zarzycki, ASP postdoctoral fellow</div><div dir="ltr" style="font-size:small;font-family:arial">Atmospheric Modeling and Predictability<br>National Center for Atmospheric Research<br><a href="http://www.colinzarzycki.com/" style="color:rgb(17,85,204)" target="_blank">http://www.colinzarzycki.com</a></div></div></div>
</div>