From quinn@pmel.noaa.gov Mon Jul 1 10:24:56 1996
Date: Fri, 28 Jun 1996 09:16:47 -0700 (PDT)
From: Patricia Quinn
To: ace1@pmel.noaa.gov
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
compared.
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 quinn@pmel.noaa.gov
NOAA/PMEL phone: 206-526-6892
7600 Sand Point Way NE fax: 206-526-6744
Seattle, WA 98115
_________________________________________________________