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results (Selvam et al.
1992
; Selvam and Joshi
1995
; Selvam et al.
1996
; Selvam and
Fadnavis
1998
; Joshi and Selvam
1999
; Selvam
2011
). Model-predicted suspended
particulate (aerosol) size spectrum (Sect. 1.6.4) is in agreement with observations
using VOCALS 2008 PCASP data (Selvam
2012
).
4.2
Data
VOCALS PCASP-B data sets were used for comparison of observed with model-
predicted suspended particle-size spectrum in turbulent atmospheric flows.
During October and November, 2008, Brookhaven National Laboratory (BNL)
participated in VOCALS (VAMOS Ocean-Cloud-Atmosphere Land Study), a mul-
tiagency, multinational atmospheric sampling field campaign conducted over the
Pacific Ocean off the coast of Arica, Chile. Support for BNL came from U.S. De-
partment of Energy (DOE)'s Atmospheric Science Program (ASP) which is now
part of the Atmospheric System Research (ASR) program following a merger with
DOE's Atmospheric Radiation (ARM) program. A description of the VOCALS
field campaign can be found at http://www.eol.ucar.edu/projects/vocals/
Measurements made from the DOE G-1 aircraft are being used to assess the
effects of anthropogenic and biogenic aerosol on the microphysics of marine stra-
tus. Aerosols affect the size and lifetime of cloud droplets thereby influencing the
earth's climate by making clouds more or less reflective and more or less long-
lived. Climatic impacts resulting from interactions between aerosols and clouds
have been identified by the IPCC Fourth Assessment Report (AR4;
2007
) as being
highly uncertain and it is toward the improved representation of these processes in
climate models that BNL's efforts are directed.
The parent data set from which the Excel spreadsheet has been derived is ar-
chived at the BNL anonymous ftp site:
ftp://ftp.asd.bnl.gov/pub/ASP%20Field%20Programs/2008VOCALS/Pro-
cessed_Data/PCASP_BPart/
Data are archived as ASCII files.
4.2.1
VOCALS 2008 PCASP-B Aerosol Size Spectrum
Data from the DOE G-1 Research Aircraft Facility operating during the 2008 VA-
MOS Ocean Cloud Atmosphere Land Study (VOCALS) 2008 based in part at Cha-
calluta Airport (ARI) north of Arica, Chile were used.
PCASP_BPart—contains detailed size-binned (30 bins, 0.1-3 µm diameter)
data obtained from the PCASP (Passive Cavity Aerosol Spectrometer Probe, Unit
B). This probe was on the isokinetic inlet in the cabin before 10/29/08. On flight
081029a it was moved to the nose pylon of the plane.
The following 17 data sets were used for the study, the file names giving Flight
Designation (yymmdd{flight of day letter}), 081014a_10.txt, 081017a_10.txt,
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