Integrated Numbers

PI: Glenn Shaw, University of Alaska Fairbanks

cn.csv is the time series of integrated numbers (cm^-3) from 20 to 600 nm for the distributions taken with the Scanning Mobility Particle Sizer (SMPS).

Columns 1, 3, 5, 7,... are day of year (noon on Jan. 1 = 1.5). Columns 2, 4, 6, 8... are the corresponding integrated numbers.

Times are UTC.

opc.csv is the time series of integrated numbers (cm^-3) from 300 to 10,000 nm for the distributions taken with the OPC. Our OPC undercounts in its smallest size bin (300 to 500 nm), so these numbers should be used only to identify trends. See the UCR/UAF comparison on the PMEL Harmony website to see why we believe that our OPC is counting accurately in all but the smallest size bin.

Columns 1, 3, 5, 7,... are day of year (noon on Jan. 1 = 1.5). Columns 2, 4, 6, 8... are the integrated numbers.

Times are UTC.

See the files for the OPC and SMPS distributions for details on sampling.

OPC

PI: Glenn Shaw, University of Alaska Fairbanks

Email: shaw@gi.alaska.edu

Aerosol number distributions at Kaashidhoo Climate Observatory, INDOEX IFP

Data in the size range from 300 to 10,000 nm (0.3 to 10 microns) was collected with a CliMET Optical Particle Counter (OPC). Samples were drawn from approximately 10 meters above sea level through the KCO aerosol stack. The OPC was directly below the terminus of the main stack. The connecting tubing was thermostatted to 70 C with an Omega temperature controller. The sheath air in the OPC was dried with molecular sieve.

The files have the naming convention : opc0304.csv

opc is a constant; the final four digits are the month and day on which the data was collected.

The files have the following format :

column 1...n : aerosol number distributions in dN/d(logD) (cm^-3) format. Unlike the SMPS distributions, d(logD) is not a constant. I have listed the midpoint diameters below with the corresponding d(logD).

Diameter (nm) d(logD)

390 0.2218

590 0.1461

840 0.1549

2200 0.699

7100 0.301

column n+1 : midpoint diameter (nm) for the distributions (they are listed above)

column n+2 : Day of year (noon on Jan. 1 = 1.5) Row 1 is the time at which the distribution in column 1 was sampled, etc...

column n+3 : Integrated number for all particles sampled by the OPC.

NOTE!!!

We believe that the OPC is undercounting in the smallest size bin. It does not agree with the SMPS in this size bin - the discrepancy is about a factor of 6. However, we have reason to believe that the OPC is sampling the remaining portion of the size range accurately. In a comparison between our OPC, and the Lasair OPC which Cal-Riverside used with their single particle mass spec. measurements, the agreement between the two counters was good (after Cal-Riverside cleaned the nozzle on their counter). See “KCO Comparison of OPC Measurements from UC Riverside and U Alaska” on the PMEL Harmony web site.

SMPS

PI: Glenn Shaw, University of Alaska Fairbanks

Email: shaw@gi.alaska.edu

Aerosol number distributions at Kaashidhoo Climate Observatory, INDOEX IFP

Data in the size range from 20 to 600 nm was collected with a TSI Scanning Mobility Particle Sizer (SMPS). Samples were drawn from approximately 10 meters above sea level through the KCO aerosol stack. From the terminus of the main stack, the samples were drawn through approximately 4 meters of 6 inch diameter PVC at a flow rate of approximately 50 lpm (liters min^-1). The SMPS sample flow was drawn from the center line of the PVC at 1 lpm. The distance from the PVC to the SMPS was less than a meter.

The samples were taken at a relative humidity of approximately 20%, which was achieved by drying the sheath air with molecular sieve. The ratio of sheath to sample flow in the differential mobility analyzer (DMA) was 5:1. Flows were checked and corrected every morning.

The individual files in the zip file have the naming convention : 2feb21.csv

feb21 is the date the sample was collected, the leading number is the sample number for that particular day.

The csv files have the following format :

columns 1...n : aerosol number distribution in dN /d(logD) (cm^-3) format - d(logD) is a constant 0.0156.

column n+1 : Diameters for the aerosol number distribution, in nanometers. These are derived from the midpoints of the bins that the SMPS uses in its sampling procedure. The reported diameters are the geometric means of the bin boundaries.

column n+2 : Day of year (noon on Jan. 1 = 1.5) Row 1 in this column is the time at which the distribution in column 1 was sampled, etc...

column n+3 : Integrated number for the SMPS distributions (cm^-3).

column n+4 : Integrated number for all particles with diameters greater than 30 nm. I use this as an internal check for another application.