Correction of the Calibration of the 3-wavelength Particle Soot Absorption Photometer (3λ PSAP)

Abstract

During the Reno Aerosol Optics Study (RAOS) in June 2002, the prototype of the 3-wavelength Particle Soot Absorption Photometer (3λ PSAP) was calibrated and a correction scheme was subsequently published (Virkkula, A., Ahlquist, N. C., Covert, D. S., Arnott, W. P., Sheridan, P. J., Quinn, P. K., and Coffman, D. J. (2005). Modification, Calibration and a Field Test of an Instrument for Measuring Light Absorption by Particles. Aerosol. Sci. Technol., 39:68–83). Unfortunately, the 3 λ PSAP flow rate had not been corrected during that analysis. The factors in the transmittance correction change after reanalysis with flow-corrected data. Reanalysis of the data also resolves an apparent discrepancy between the 1 λ PSAP and the 3 λ PSAP, and the two instruments now agree well.

Acknowledgments

This work was supported by the EU FP6 Integrated Infrastructures Initiatives (I3) project EUSAAR (European Supersites for Atmospheric Aerosol Research Project FP6-026140) and by the Academy of Finland as part of the Centre of Excellence Program (project no. 1118615). The RAOS experiment was supported by the U.S. Department of Energy Atomic Radiation Measurement (ARM) and the NOAA Aerosol-Climate Interactions Program.