From Mon Jul  1 10:25:10 1996
Date: Fri, 28 Jun 1996 12:50:09 -0600 (MDT)
From: Donald Lenschow 
Subject: atmospheric dynamics summary

Summary of the Monday 24 June session on ATMOSPHERIC DYNAMICS

            D. Lenschow   --    Draft     6/26/96

The session on atmospheric dynamics decided to split this topic by scales
of motion:  large scale, which involves scales larger than the aircraft flight
patterns (about 100 km), emphasizing mainly synoptic scale; and small scale, 
which involves scales up to about the scale of aircraft flight patterns.  

Large scale subtopics that were discussed are:

1) Aircraft experiment trajectories - There is a general need for trajectories
to coincide with the time and locations of the aircraft flight patterns.
Steve Siems has volunteered to provide these trajectories for the flights out
of Tasmania using the Australian GASP model.  Requests for these trajectories,
which can go backwards 3 to 5 days, should be forwarded to Steve S.  
Steve Businger volunteered to provide trajectories for the transit flights 
flown from bases on the way to and returning from Tasmania.  Requests 
for these trajectories should be addressed to Steve B.  
There are already available trajectories once a day for the 
Cape Grim site and for the ships.  ECMWF data may be available for e.g.
trajectory analyses through Brookhaven National Laboratory.

2) Air masses - Phil Austin is planning to carry out a study of cloud
properties (e.g. average droplet radius) using satellite data for favorable
times and places during the experiment, particularly when in situ aircraft
data may be available.  Those interested in this topic may want to discuss
this with Phil.

3) Soundings - All the balloon soundings are now available on the NET.  
Aircraft soundings will not be generally available, although Nemal Gamage
has volunteered to provide high-rate aircraft soundings that may be requested.
In addition, CODIAC will soon be able to plot data for specified time periods
using the low-rate (1-sec.) data, so CODIAC users will then be able to obtain

Small-scale subtopics are:

1) Airplane circles - Paul Krummel has carried out calculations of divergence 
and vorticity for most of the flights containing circles.  Qing Wang has 
carried out calculations of fluxes of water vapor, temperature and momentum 
for some of these flights, and plans to continue doing more of them.  The 
water vapor flux estimates have been combined with mean profiles to estimate 
entrainment velocity.  Ozone is another potential scalar for this technique, 
but is not yet available for flux calculations.  Lidar data should be useful 
for estimating the depth of the boundary layer, and as a replacement for the
radar altimeter when cloud conditions permit, but is also not yet available.

2) Entrainment estimates from ships - Calculations of entrainment rate from
the ships using "box model" techniques for e.g. ozone, and estimates of the
boundary-layer depth from the ship-mounted ISS are planned by Eric Saltzman.  
Possibly also this may include combining large-scale estimates of mean 
vertical motion with ship estimates of boundary-layer height.  

3) Divergence estimates will also be available from the Lagrangian balloons,
which will be analyzed by Steve Businger.

Finally, we discussed the importance of making instrument intercomparisons
between the different platforms (e.g. ships and aircraft, or fixed sites
and aircraft) whenever possible.