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clap > Continuous Light Absorption PhotometerVAP Type(s) > Baseline • External • Guest

The continuous light absorption photometer (CLAP) operates on the same principle as the particle soot absorption photometer (PSAP), i.e., continuously measuring transmission through a filter substrate as sample air is drawn through it. The absorbing aerosol particles are collected in the filter.

The CLAP is part of the aerosol observing system (AOS).


  • Fixed
  • AMF1
  • AMF2
  • AMF3


Li H, G McMeeking, and A May. 2020. "Development of a new correction algorithm applicable to any filter-based absorption photometer." Atmospheric Measurement Techniques, 13(5), 10.5194/amt-13-2865-2020.


Jensen M, E Bruning, D Collins, A Fridlind, P Kollias, C Kuang, D Rosenfeld, A Ryzhkov, A Varble, SD Brooks, S Collis, E Defer, J Fan, J Flynn, S Giangrande, R Griffin, J Hu, R Jackson, M Kumjian, T Logan, T Matsui, G McFarquhar, C Nowotarski, J Quaas, M Oue, R Sheesley, J Snyder, P Stier, S Usenko, S van den Heever, M van Lier Walqui, Y Wang, Y Xu, and G Zhang. 2019. Tracking Aerosol Convection Interactions ExpeRiment (TRACER) Science Plan. Ed. by Robert Stafford, DOE/SC-ARM-19-017.


Cappa C, R Kotamarthi, A Sedlacek, C Flynn, E Lewis, A McComiskey, and N Riemer. 2016. Absorbing Aerosols Workshop Report. Ed. by Robert Stafford, DOE/SC-0185.


Sherman JP, PJ Sheridan, JA Ogren, E Andrews, D Hageman, L Schmeisser, A Jefferson, and S Sharma. 2015. "A multi-year study of lower tropospheric aerosol variability and systematic relationships from four North American regions." Atmospheric Chemistry and Physics, 15(21), 10.5194/acp-15-12487-2015.


Jefferson A. 2014. Continuous Light Absorption Photometer (CLAP) Final Campaign Report. U.S. DOE, Office of Science, Office of Biological and Environmental Research. DOE/SC-ARM-14-013.

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