From Mon Jul  1 10:24:56 1996
Date: Fri, 28 Jun 1996 09:16:47 -0700 (PDT)
From: Patricia Quinn 
Subject: working group reportACE 1 Data Workshop

Summary of Working Group on Aerosol Characterization (Surface Platforms)
P. Quinn, June 27, 1996

The Surface Aerosol Characterization Working Group discussed the 
collaborative data analysis that is needed within single platforms as 
well as between platforms to 1) compare different measurement methods 
that will be used to derive a given parameter and 2) perform the local 
closure experiments outlined in the ACE 1 Science and Implementation 
Plan.  The measurement comparisons outlined below are considered to be a 
first step in the local closure experiments that are described later in 
this summary.

1.  Comparisons within a platform.

a.  Chemistry.

i.  Mass size distributions derived from the Berners, MOUDIs, and Sierras 
will be compared in their raw form.  In addition, a lognormal fit will be 
applied to the raw data and the fitted size distributions will be 
compared.  P. Quinn (Disco) and H. Sievering/A. Middlebrook (Cape Grim) 
were put in charge of Platform Aerosol Chemical Characterization.  Their 
duties include compiling all available aerosol chemical information 
(including gas phase ammonia and sulfur dioxide) from the respective 
platforms, identifying consistencies and inconsistencies in the data, and 
characterizing the chemistry in terms of prevailing meteorological 
conditions.  Comparisons of impactor data will fall within this activity.

b.  Physics.  

i.  Density adjustment of the APS data.  In the Column Closure Working 
Group P. Quinn (Disco) and S. Howell (Cape Grim) were identified to 
provide density values based on the impactor mass size distributions.

ii.  Inversion of number size distributions.  Disco and Cape Grim data 
will be sent to Frank Stratmann for the inversion (Macquarie Island data 
has already been submitted to Frank) and the inverted data will be 

iii.  Lognormal fitting of data to derive N(tot), Dg, and Sg for each 
mode.  Derek Coffman will develop a fitting program that allows for the 
recognition of up to 5 modes.  The fitting program will be made available 
for each group to fit their own data.

c.  Chemistry/Physics

i.  Impactor mass size distributions will be compared to volume size 
distributions derived from the fitted number size distributions.  Both 
the raw and fitted impactor size distributions will be used in the 
comparison.  These comparisons will be a part of the mass closure studies.

2.  Local Closure.  People were identified to coordinate the local 
closure experiments at each of the surface platforms.

a. Local Closure at Cape Grim

i.  CCN:  J. Gras
ii.  Hygroscopic growth:  D. Covert
iii.  Mass:  S. Howell
iv.  Scattering:  M. Rood

b.  Local Closure on the Disco

i.  Hygroscopic growth:  E. Swietlicki
ii.  Mass:  P. Quinn
iii.  Scattering:  P. Quinn

c.  Local Closure at Macquarie

i.  CCN:  S. Kreidenweis

3.  Comparisons Between Platforms.  Two types of comparisons are 
possible:  those when the Disco was near Cape Grim or Macquarie and those 
when platforms were experiencing similar meteorological conditions.  For 
the latter, a general meteorological analysis is needed for the entire 
region and period of the intensive. In addition, more complete analyses 
are needed for specific conditions or time periods of interest.  No one 
was identified to do the met analysis or to take the lead in 
inter-platform comparisons.  A. Wiedensohler, however, is planning to do 
a statistical analysis of the number size distribution from all the 
surface platforms in the context of a meteorological synopsis. 

Patricia Quinn        
NOAA/PMEL                       phone:  206-526-6892
7600 Sand Point Way NE          fax:  206-526-6744
Seattle, WA  98115