caps-pmex: Cavity Attenuated Phase Shift Extinction Monitor

The cavity attenuated phase shift extinction monitor is an optical extinction spectrometer that measures aerosols, broadband scatterers and absorbers of light that interact with solar radiation and influence the Earth’s radiation balance. The CAPS PMex uses a visible-light-emitting diode (LED), a sampling cell incorporating two high-reflectivity mirrors centered at the wavelength of the LED, and a vacuum photodiode detector.



  • Fixed
  • AMF1
  • AMF2
  • AMF3

Active Instrument Locations

Facility Name Instrument Start Date
Lamont, OK (Extended and Co-located with C1) 2016-11-15


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Dubey M, A Aiken, LK Berg, A Freedman, and K Gorkowski. 2016. Two-Column Aerosol Project: Aerosol Light Extinction Measurements Field Campaign Report. Ed. by Robert Stafford, DOE ARM Climate Research Facility. DOE/SC-ARM-16-047.

Sedlacek AJ. 2016. Cavity Attenuated Phase Shift Monitor Instrument Handbook. Ed. by Robert Stafford, DOE ARM Climate Research Facility. DOE/SC-ARM-TR-155.


Petäjä T. 2013. Science Plan Biogenic Aerosols Effects on Clouds and Climate (BAECC). ARM user facility. DOE/SC-ARM-13-024.


Wood R, CS Bretherton, CR Mecheso, RA Weller, B Huebert, F Straneo, BA Albrecht, H Coe, G Vaughan, P Daum, C Fairall, D Chand, L Gallardo Klenner, R Garreaud, C Grados, DS Covert, TS Bates, R Krejci, LM Russell, S de Szoeke, A Brewer, SE Yuter, SR Springston, A Chaigneau, T Toniazzo, P Minnis, R Palikonda, SJ Abel, WO Brown, S Williams, J Fochesatto, J Brioude, and KN Bower. 2011. "The VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx): goals, platforms, and field operations." Atmospheric Chemistry and Physics, 11(2), 10.5194/acp-11-627-2011.


Ghan S and SE Schwartz. 2007. "Aerosol Properties and Processes: A Path from Field and Laboratory Measurements to Global Climate Models." Bulletin of the American Meteorological Society, 88(7), 10.1175/bams-88-7-1059.

Kassianov EI, C Flynn, TP Ackerman, and JC Barnard. 2007. "Aerosol single-scattering albedo and asymmetry parameter from MFRSR observations during the ARM Aerosol IOP 2003." Atmospheric Chemistry and Physics, 7(12), 10.5194/acp-7-3341-2007.

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