Aerosol Properties derived from TDMA Measurements (TDMADAP)

Information updated on April 8, 2010, 9:05 pm GMT


General Data Description

The Tandem Differential Mobility Analyzer (TDMA) is an instrument to measure dry size distribution and the size resolved hygroscopic growth factors. In its standard operating mode, the dry aerosols are separated into size bins by the first DMA, then exposed to 85% relative humidity and the resulting hygroscopic growth factor distributions for each dry size bin scanned by the second DMA. The aerosol properties described here are derived from the TDMA data by value added procedures created and run by Don Collins at Texas A & M University.

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Data Stream Names

Measurement Description


cumulative_ccn: 
  Expected cumulative CCN concentration as a function of supersaturation based on measured size 
  and hygroscopicity distribution, 1/cm^3

differential_ccn: 

  Expected differential CCN concentration as a function of supersaturation based on measured size
  and hygroscopicity distribution, 1/cm^3

Texas A & M provides their own auxiliary QC values, as follows:

  • 0 indicates no flag
  • 1 indicates that the distribution is somewhat unusual and may be inaccurate. These distributions are used in the calculated products available in other datastreams.
  • 2 indicates that the distribution is highly unusual and is likely inaccurate. These distributions are not used in the calculated products available in other datastreams.

Temporal Coverage

Data are available from
  • 2005-10-07 through 2007-12-26 and
  • 2009-01-01 through 2009-05-31.

The data are processed periodically at Texas A&M and will eventually be available for the entire period of the TDMA deployment.

Area Covered

Data are collected at the SGP Central Facility site, in Oklahoma.

Data Stream Inputs

sgptdmaccncollX1.00 consisting of two files:
   mmddyyyy_cumulative_CCN.txt
   mmddyyyy_differential_CCN.txt

To determine the CCN AQC values, the AQC values from the corresponding size distribution and hygroscopic netCDF files are read: 

   sgptdmasizeC1.b1
   sgptdmahygC1.b1

Notification Form Link

Notification Form

Contacts

Acronyms

TDMA - Tandem Differential Mobility Analyzer
ACRF - ARM Climate Research Facility
CCN  - Cloud Condensation Nuclei

Citable References

Gasparini, R., Collins, D. R., Andrews, E., Sheridan, P. J., Ogren, J. A., and Hudson, J. G., 2006b. “Coupling aerosol size distributions and size-resolved hygroscopicity to predict humidity-dependent optical properties and CCN spectra,” Journal of Geophysical Research – Atmospheres, 111, art. No. 6092.