From Wed Jul 17 10:39:54 1996
Date: Fri, 05 Jul 1996 10:48:41 -0700 (PDT)
From: "Dr. Barry Huebert" 
To: ACE-1 List 
Subject: Workgroup report for the C-130

REMAINING C-130 ISSUES		B. Huebert, 7/4/96

The C-130 group concluded that most of the aircraft issues had been
covered in earlier sessions. However, we did discuss the CAI, the
comparability of data from different sampling tubes in the CAI, and plans
to evaluate the CAI's efficiency.

Rodney Weber noted that the UM UCN instrument often showed much more
evidence of droplet shatter than Tony Clarke's (UH). When they replumbed
so they could draw air from either sampling tube, the UM tube (which was
apparently in the middle of the pack at the rear of the CAI), usually had
much more shatter than the UH tube. This was not always the case, however,
as the droplet shatter maximum moved around a bit. This suggests that some
cloud droplets may penetrate to the sampling plane in a kind of jet, whose
position at the sampling plane depends on aircraft yaw, sideslip, pitch,
TAS, or other factors. Rodney volunteered to look into the factors which
affected the shatter at each location. He will include all the CN counters
on board, including Hudson's and Kok's. CAINE-2 flow measurements will
also be useful in looking for nonuniformities in the CAI flow that might
contribute to this phenomenon.

Clearly, knowing the extent to which the CAI was able to provide similar
air to many samplers is critical to interpreting differences between
related measurements. We also need to know its passing efficiency vs size
to see how much of the larger aerosols actually made it to our sampling
devices. Some of that can be done using existing data from ACE-1.
Huebert's group is now ready to compare sodium and other ions from their
external sampler with that from the impactors that sampled from the CAI.
They have recently measured the passing efficiency of their plumbing and
impactors with monodisperse aerosols in the laboratory. This information,
when combined with the internal/external differences and MASP size
distributions, should permit us to make a crude estimate of the CAI size
cut. The other CAI evaluation using ACE-1 data, a comparison of
Baumgardner's MASP (external) and Clarke's (internal) OPC size
distributions, will have to await a recalibration of Clarke's OPC, which
may not be completed until the end of 1996. This comparison will require
that Steve Howell use his thermodynamic model to remove the water from the
MASP distribution or add it to Clarke's, since one is measured dry and the
other at ambient humidity.

Huebert's group is also requesting C-130 hours in the spring of 1997
(CAINE-2) to do two kinds of CAI tests. One is the measurement of
velocities at a variety of points across the sampling plane and at the
ends of each diffuser section in the CAI. This study, done on short
flights out of Jeffco, will look for nonisokinetic conditions at the
sampling plane, regions of excessive turbulence, and the possibility of
jets in certain regions. The other is a set of flights in a marine
location, in which the CAI will be carefully washed before sampling,
exposed for 1-2 hours in the marine boundary layer, and then disassembled
so that certain parts can be extracted to measure the amount of sea-salt
deposited on them. An new TSI aerodynamic particle sizer (APS), which has
been designed to work well on aircraft, will be used alongside a MASP to
evaluate the passing efficiency vs size.

From Wed Jul 17 10:40:03 1996
Date: Fri, 05 Jul 1996 22:44:12 -1000 (HST)
From: Tony Clarke 
To: "Dr. Barry Huebert" 
Cc: ACE-1 List 
Subject: Re: Workgroup reports for C-130 and Lagrangians


A small correction to your C-130 report.  Actually it is not true that 
knows the status of the TDDR data (Valero, Bucholtz).  As I reported at 
the meeting and indicated in my "Radiative closure" report, most of the 
TDDR data apears to be good and it is the expectation of Anthony Bucholtz 
to have this data in the data set by September.  They have been busy on 
other field campaigns since ACE-1.

Also my CN and UCN counter data should be ready in a few weeks.  This 
will consist of files edited for shatter and files with shatter included 
so that others might evaluate their data (eg. Lynn Russell).

Our DMA and OPC data should be out before AGU.