Title: C130 Particle Concentration Data

Contact:

   Peter McMurry
   Particle Technology Laboratory, 125 Mechanical Engineering
   University of Minnesota
   111 Church Street S.E.
   Minneapolis, MN  55455
   USA
   (612) 625-3345
   (612) 625-6069
   E-Mail Address: McMurry@me.umn.edu

Or

   Rodney J. Weber
   Environmental Chemistry Division
   Brookhaven National Laboratory
   Bldg. 426 (51 Bell Ave.) PO Box 5000
   Upton NY 11973-5000
   Phone:     (516) 344-6198
   Fax:       (516) 344-2887
   Secretary: (516) 344-3275
   E-Mail Address: rweber@mail.bnl.gov

   Secretary: Maggie Marsch or Pat Kriss  Internet:  mmarsch@bnlux1.bnl.gov


Data Set Description:

FILE START TIME (UTC) = MMDDHHMMSS = 1031161438
FILE START TIME (UTC)= 1223025143
PI NAME = MCMURRY
FACILITY = C130
DATA VERSION = 1

Measurements are of total concentration = number/cm^3 larger than 3 nm
measured with the University of Minnesota UCNC and ultrafine particle
concentration = nominal number/cm^3 between 3 and 4nm measured with the
pulse height analysis method.  For a detailed explanation of ultrafine
concentration see; Weber et al. J. Atms. Sci. v52, 2242, 1995; Saros et at.
Aerosol Sci. Tech., v25, 200, 1996.  The data reported are at ambient
temperature and pressure.

Missing value indicator = -9.99

Periods of droplet shatter in the community aerosol inlet resulted in
measurements that are not representative of ambient particle
concentrations.  Periods of good data and periods when shatter was
suspected are identified with the flag, "SHATTER FLAG". SHATTER FLAG=1 are
episodes of no cloud droplet shatter; SHATTER FLAG = 0 are episodes of
likely cloud droplet shatter (i.e., measured concentrations are likely a
sampling artifact).

Sample air was extracted from the community aerosol inlet.  The sample air
was not altered.  The sampling interval was nominally 60s.  Live time
sampling and dilution of sample aerosol when necessary eliminated particle
coincidence errors.  The detection efficiency of the UCNC was calibrated at
the UW/PMEL ACE-1 CNC workshop in Seattle, WA, August 1995.  The results
are included in the ACE-1 data set.

Sampling losses have not been accounted for.  It is estimated that for 3nm
particles diffusion losses in the community aerosol inlet are on the order
of 50% and in our sampling train less than 10% (ignoring bends).  Larger
particles will have lower diffusion losses.

Uncertainty in the reported concentrations (N) is due to counting (C),
sampling time (T) and sample flow rate (Q) uncertainties , where;
(dN/N)^2=(dC/C)^2+(dQ/Q)^2+(dT/T)^2; C=(NQT), T=60s, Q=0.39cm3/s;
(dC/C)=(NQT)^-0.5 (i.e., Poisson statistics), (dT/T) is small, (dQ/Q) is
estimated to be 5%.


Format: space-delimited ASCII with fields:

StartDate(YYYY/MM/DD) (UTC)
StartTime(HH:MM:SS) (UTC)
StartLat(degN)
StartLon(degE)
StartAlt(m)
StopDate(YYYY/MM/DD) (UTC)
StopTime(HH:MM:SS) (UTC)
StopLat(degN)
StopLon(degE)
StopAlt(m)
Sample_No.
Total(cm-3)
Ultrafine(cm-3)
No_Shatter_Flag


File Name Conventions:
   550_rfxx.dat where xx is the flight number.
   An example for flight 26 is 550_rf26.dat.


References:
Weber et al. J. Atms. Sci. v52, 2242, 1995;
Saros et at. Aerosol Sci. Tech., v25, 200, 1996.