Tropospheric Chemistry: Instruments

AFSR on rooftop in Boulder

AFSR on rooftop of NOAA David Skaggs Research Center in Boulder, Colorado.

AFSR (Actinic Flux SprectroRadiometer) decommissioned

Principle of the Measurement


Species Measured

Photolysis rates via spectral actinic flux

Time Response

1 Second


custom built

Field Projects

  • NEAQS 2002
  • ICARTT 2004
  • TEXAQS 2006
  • ARCPAC 2008
  • CalNex 2010


Harald Stark

Key Publications

Stark, H., B. M. Lerner, R. Schmitt, R. Jakoubek, E. J. Williams, T. B. Ryerson, D. T. Sueper, D. D. Parrish, and F. C. Fehsenfeld, Atmospheric in situ measurement of nitrate radical (NO3) and other photolysis rates using spectroradiometry and filter radiometry, Journal of Geophysical Research, doi:10.1029/2006JD007578, 2007.