Techniques and Instruments:

1. Atmospheric wavelength dependent actinic flux measurements from aircraft and ground based sites. The actinic fluxes are measured with Scanning Actinic Flux Spectroradiometers (SAFS) and CCD Actinic Flux Spectroradiometers (CAFS). These actinic fluxes are used for calculation of atmospheric photolysis frequencies employing the temperature dependent molecular absorption cross sections and quantum yields and calculation of ozone column abundances above the aircraft using radiative transfer modeling to determine the direct radiation component.

2. Atmospheric wavelength dependent direct beam irradiance from aircraft. The irradiance measurements are performed with a solar tracking Direct beam Irradiance Airborne Spectrometer (DIAS). The direct beam irradiances are used for calculation of line of sight ozone and wavelength dependent aerosol optical depths.