| Summary: | Progress Code: completed Statement: MAX-DOAS mirror angle function not functioning properly on 16 and 17 September until 1010 UT The controlling computer froze a number of times throughout the voyage which caused a few hours of data loss. See log for details. The current data set contains spectral atmospheric measurements from: - Multi-Angle Differential Optical Absorption Spectrometer (MAX-DOAS) - built in-house at NIWA Lauder by Dr Karin Kreher, Mr Paul Johnston and Mr Alan Thomas. Instrument description and setup details: MAX-DOAS Instrument Description: The MAX-DOAS instrument consists of a Czerny-Turner type ISA HR320 flat-field spectrograph with a focal length of 320 mm and an aperture ratio of F/4. The array detector is a Hamamatsu C7042 detector head with S7032-1007 sensor chip. The chip is back-thinned, allowing light to enter from the rear of the silicon substrate, which substantially increases the quantum efficiency over the whole spectral range, especially in the UV region (less than 400 nm). The sensitivity in the UV is important in order to obtain a good signal-to-noise ratio for BrO measurements. The detector signal is then passed to the computer via a 16-bit analogue to digital converter card. The detector is cooled to -20oC using a Peltier cooler to minimise the dark current noise caused by thermally excited electrons. The entrance optics consisted of an angled telescope mirror that reflects the measured light down through a focusing lens onto the entrance of a quartz fibre optic bundle leading into the spectrograph. The field of view of the telescope is ~0.5o. A webcam, also housed close to the entrance optics, records images of the sky in the spectrometer viewing direction at one minute intervals. These images are included in the dataset. Instrument Setup: The spectrometer was scanning wavelength regions in the UV-Vis region with a variable resolution spread over the pixel array CCD. Spectra were taken at multiple viewing angles (1,2,3,4,6,8,15,30,90o) in the open water and ...
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