Title: C130 Composite Particle Probe Spectra

Contact:

   Darrel Baumgardner
   NCAR/ATD/RAF
   P. O. Box 3000
   Boulder, CO  80307
   USA
   303-497-1054
   303-497-1092
   Web Access: http://chinook.atd.ucar.edu/~darrel
   E-Mail Address: darrel@ncar.ucar.edu


Data Set Description:

A new set of data files are now available that contain a
composite size distribution synthesized from
measurements with the C-130 PCASP, FSSP-300, FSSP-100
and 260-X. This composite size distribution represents a
reprocessing of the FSSP-300, FSSP-100 and 260-X
measurements. The changes from the netCDF data files
that are presently on the NCAR MASS store are as
follows:

1) The composite distribution uses only portions of each
probe's measurements and takes advantage of the
overlapping size ranges of each of the probes. The
nominal size ranges of these four probes are:

   PCASP     -  0.1 to 3.0 um.
   FSSP-300  -  0.3 to 20.0 um.
   FSSP-100  -  2.0 to 47 um
   260-X     - 10.0 to 620 um.

 Normally, the first channel of each of these probes is
suspect because of electronic noise or sunlight
contamination, so the overlapping provides a means of
covering these channels with another instrument, with
the exception of the PCASP, where the first channel is
not included in the processing at all. The composite
distribution is made up as follows:

   PCASP     -  0.161 to .303 um
   FSSP-300  -  0.415 to 4.1 um
   FSSP-100  -  5.8 to 49  um
   260-X     - 45.0 to 605 um.

2) The FSSP-300 calibrated to match a particle
refractive index of 1.40, instead of the factory
calibration at 1.58. Some channels were combined to
minimize the problems of Mie sizing ambiguities.

3) A better calibration was applied to the FSSP-100 and
the last three channels were combined to take care of
Mie scattering ambiguities in that size range.

4) The OAP was re-calibrated and found to have a size
resolution of 17 um rather than 10 um. There was a
change made in the field to increase signal to noise
ratio and the resolution was changed at that time. This
affects not only the sizing, but also the sample volume.

   The size distributions are ten second averages throughout the
flights. Darrel Baumgardner can make one second data
available upon request. The 43 channels of data are in
units of cm-3. In the header of each file Darrel Baumgardner has
included the midpoint and width of each channel. The
concentrations should be divided by the width when
plotting size distributions. The average channel
diameter can be used when calculating volumes and
surface areas from the size distributions.

   There are several caveats. Darrel Baumgardner has not yet done an
extensive quality assurance check on these files. Darrel Baumgardner will
be doing so over time but at this point caution is
warranted. There could be occasional spikes and noise
that will contaminate the spectra. Also, the PCASP had a
leak in its plumbing until flight 11, so Darrel Baumgardner have zeroed
its values in flights 4-10. Darrel Baumgardner would appreciate any
feedback regarding problems that may be detected in the
data files.

Format:

One flight per file, with one record per line.
Parameters are separated by spaces in the following order:

Date UTC (YYYY/MM/DD)
Time UTC (HH:MM:SS)
Latitude (deg N)
Longitude (deg E)
Altitude (m)
Spectra Segment #1 (channels 2 to  4 from the PCASP)
Spectra Segment #2 (channels 2 to 16 from the FSSP-300)
Spectra Segment #3 (channels 2 to 12 from the FSSP-100)
Spectra Segment #4 (channels 2 to 15 from the 260x)

The measurements from the PCASP, FSSP-300, FSSP-100 and 260-X
have been combined to produce a continuous size spectra from
approximately 0.18 - 600 um.
The spectra are averaged over 10 second intervals.

The Segment # 1 average size/channel is:
  0.179  0.216  0.269
The Segment # 1 channel widths are:
  0.036  0.037  0.069
The Segment # 2 average size/channel is:
  0.438  0.483  0.527  0.569  0.614  0.663  0.725  0.784
  0.823  0.870  0.938  1.025  1.622  3.048  4.003
The Segment # 2 channel widths are:
  0.045  0.046  0.042  0.042  0.049  0.048  0.075  0.044
  0.034  0.060  0.075  0.099  1.097  1.753  0.157
The Segment # 3 average size/channel is:
   7.4  10.7  13.5  16.8  20.1  24.2  27.7  30.9  35.9  40.4  45.5
The Segment # 3 channel widths are:
   3.3   1.9   3.8   2.8   3.8   4.4   2.5   4.0   6.0   3.0   7.0
The Segment # 4 average size/channel is:
 110.5 178.5 246.5 314.5 382.5 450.5 518.5 586.5 654.5 722.5
 790.5 858.5 926.5 994.5
The Segment # 4 channel widths are:
  68.0  68.0  68.0  68.0  68.0  68.0  68.0  68.0  68.0  68.0
  68.0  68.0  68.0  68.0


File Name Conventions:
   rfxxx.dat where xxx is the flight number.
   An example for flight 26 is rf26.dat.

References: None.