A UV/visible diode array spectrometer was installed at Arrival Heights (93/94 seasons) for zenith skylight measurements of Chlorine Dioxide (OClO) and Bromine Monoxide (BrO) in two wavelength ranges, in the spring to see the perturbation of chlorine chemistry in the early spring with high levels of active chlorine and bromine being converted back to the reservoir (HCl) and active nitrogen levels ... recovering as the season progresses. Raw data is times and recorded spectro of scattered light. The derived data are column amounts of OClO and BrO. The instrument was originally configured with a photodiode array (DA) detector, but was reconfigured with a CCD detector and labview software in 2007. It also was placed in a temperature controlled enclosure to improve stability and a modern operating system and controlling software.
"Raw" data are sometimes recorded spectra of scattered light. "Derived" data are column amounts of NO2, OCIO, BrO and ozone.