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12-July-2011
PLEASE NOTE: These data are subject to revision and, thus, are password protected. If you wish to have the data please contact Jim Johnson or Timothy Bates for a password.
The first two data sets include particle number-size
distributions in the diameter range of 0.020 to 0.8 micrometers
Stokes diameter made with an "Aitken" DMPS (20 to 200 nm)
and an "Accumulation" DMPS (200 to 800nm). All
measurements were made at a relative humidity of 60%. The
distributions have been cleaned of all data from times of instrument
malfunction or calibration. Additionally, the data set with “filter”
in the name contains only those distributions where the total CN
concentrations were stable over the course of each measurement have
been included.
files: CALNEX_nsd_dmps_vX.csv
CALNEX_nsd_dmps_filter_vX.csv
The second two data sets include particle number-size
distributions in the diameter range of 0.96 to 10 micrometers
aerodynamic diameter. The APS diameters are aerodynamic and have not
been corrected to Stokes diameter via calculation or estimates of
particle density. The APS data larger than 10 micrometers are not
useful due to significant particle losses in the inlets including
the ship's sampling mast, distribution tubing and APS inlet. All
measurements were made at a relative humidity of 60%. The APS data
have been cleaned exactly like the DMPS files described above.
file: CALNEX_nsd_aps_vX.csv CALNEX_nsd_aps_filter_vX.csv
The third two data sets include particle number-size
distributions in the diameter range of 0.020 to 10 micrometers
Stokes diameter. The distributions are a combination of DMPS and APS
data where the APS data have been converted to Stokes diameters.
This conversion was done using densities calculated from measured
chemistry. The diameter channels in the overlap region were chosen
in the following manner: the last DMPS channel was discarded and,
after converting to Stokes diameters, the first APS diameter channel
that was larger than the last valid DMPS channel was chosen as the
first APS channel. Each combined distribution was regridded onto a
common set of diameters. Finally, the regridded distributions were
cleaned to eliminate values at the larger sizes from the APS where
“phantom” counts resulted in a spurious coarse mode in
the surface and volume distributions. All measurements were made at
a relative humidity of 60%.
file: CALNEX_nsd_dmps_aps_vX.csv
CALNEX_nsd_dmps_aps_filter_vX.csv
The fifth two data sets include particle mass-size
distributions in the diameter range of 0.020 to 10 micrometers
Stokes diameter, calculated from the number-size distributions
described in the section 3 above. The conversion of number to mass
was done using densities calculated from measured chemistry.
(download only – not available for plotting)
file:
CALNEX_msd_dmps_aps_vX.csv CALNEX_msd_dmps_aps_filter_vX.csv
keyword |
description |
---|---|
nsd |
number size distribution |
msd |
mass size distribution |
ambient |
at ambient temperature and RH |
filter |
cleaned of periods where the CN concentrations were not stable |
Table 1: Filename keywords
More information about these data can be found by clicking on the blue "Instrument Information" tab above.
The following files are available for downloading. Please note: one data file may cover more than one time period, thus,some files may be listed more than once. All files are in csv (comma separated value) format. After several lines of general information each file starts with a first row that contains the particle diameter in microns for that column. The first column contains the date/time in Day-of-Year, DOY. DOY 32.5 is 1200 noon UTC on 1-February. All data are in units of dN/dlog10(Dp), N/cm^3. Missing data are designated by a -99 or a -999.
Start Date | End Date | ASCII file |
---|---|---|
14-May-2010 | 08-Jun-2010 | CALNEX_nsd_dmps_v1.csv |
14-May-2010 | 08-Jun-2010 | CALNEX_nsd_dmps_filter_v1.csv |
14-May-2010 | 08-Jun-2010 | CALNEX_nsd_aps_v1.csv |
14-May-2010 | 08-Jun-2010 | CALNEX_nsd_aps_filter_v1.csv |
14-May-2010 | 08-Jun-2010 | CALNEX_nsd_dmps_aps_v1.csv |
14-May-2010 | 08-Jun-2010 | CALNEX_nsd_dmps_aps_filter_v1.csv |
14-May-2010 | 08-Jun-2010 | CALNEX_nsd_dmps_aps_ambient_v1.csv |
14-May-2010 | 08-Jun-2010 | CALNEX_nsd_dmps_aps_ambient_filter_v1.csv |
14-May-2010 | 08-Jun-2010 | CALNEX_msd_dmps_aps_v1.csv |
14-May-2010 | 08-Jun-2010 | CALNEX_msd_dmps_aps_filter_v1.csv |
14-May-2010 | 08-Jun-2010 | CALNEX_msd_dmps_aps_ambient_v1.csv |
14-May-2010 | 08-Jun-2010 | CALNEX_msd_dmps_aps_ambient_filter_v1.csv |
U.S.Dept of Commerce / NOAA / OAR / PMEL / Atmospheric Chemistry