[Baps] Erika Barth to be Monday's MASS speaker

[Angela Marie Zalucha]

================================================================
=============  M.I.T. Atmospheric Seminar Series ===============
================================================================
               Monday, November 23 at noon in 54-915
================================================================
                          Erika Barth
                 Southwest Research Institute
    "Cloud Microphysics and Convection in Titan's Atmosphere"
================================================================
====== http://paoc.mit.edu/paoc/events/seminars/mass.htm =======
================================================================

Abstract:
It is now well established that clouds form in Titan's atmosphere.  Polar 
clouds existed as a prominent feature in the southern hemisphere for a 
number of years.  Mid-latitude clouds, clustered near 40 deg. S latitude, 
have been observed by both the Cassini spacecraft and ground-based 
telescopes. At the Huygens landing site, about 10 deg. S of the equator, 
optically thin condensate layers were observed in the mid to lower 
troposphere.  The rapid lifetimes and common heights of the South Pole and 
mid-latitude clouds, in particular, point to a convective origin.  To 
understand the conditions necessary for convective clouds to form in 
Titan's atmosphere, we have developed the Titan Regional Atmospheric 
Modeling System. TRAMS is a three-dimensional, time-dependent, coupled 
fully compressible dynamic and microphysical model capable of simulating 
methane and ethane clouds. I will discuss a number of simulations, which 
have shown that the types and observable properties of the clouds able to 
form in Titan's atmosphere are strongly tied to the amount of methane 
present.  For example, for cloud tops to reach the tropopause requires a 
surface humidity of greater than 60%, whereas cloud tops below 30 km occur 
for only 50% humidity. The amount Convective Available Potential Energy 
(CAPE) at the Huygens landing site is insufficient for optically thick 
convective clouds to form.  The appearance of convective clouds at the 
South Pole and mid-latitudes then points to a more humid environment.


Upcoming seminars:

Nov. 30 - Ann Marie Carlton (EPA): To What Extent Can Biogenic SOA be 
Controlled?

Dec. 7 - Mike Previdi (Columbia/LDEO): TBA