A non-scanning UV spectroradiometer for long-term measurements in polar regions

• Main Authors: Wuttke, Sigrid, Schrems, Otto, Hanken, T., Wiencke, Christian
• Format: Conference Object
• Language: unknown
• Published: 2005
• Subjects: Alfred Wegener Institute; Antarc*; Antarctic; Spitsbergen
• Online Access: https://epic.awi.de/id/eprint/14311/; https://hdl.handle.net/10013/epic.24628

Spectral UVB irradiance (280-320 nm) is being monitored at the NDSC primary site at Ny-Alesund, Spitsbergen (78.9° N, 11.9° E) and at the German Antarctic Neumayer Station (70.65° S, 8.25° W, complementary NSDC site) by the Alfred Wegener Institute for Polar and Marine Research (AWI). A third polar site operated by AWI, where spectral UV irradiance is monitored, is the Dallmann Laboratory/Jubany Station at the Antarctic Pensinsula (62° 14 S, 58° 40W).The UVB-spectroradiometer is based on a Bentham DTM150 double monochromator and a Microchannel Photomultiplier Plate with 32 channels. Additional instruments were installed at Ny-Alesund in 2000 and at Neumayer station in 2001 to cover also the UVA range (320-400 nm) of the solar spectrum. This instrument contains a single monochromator as the dynamic range is low in the UVA compared to the UVB. The detector is a photodiode array with 256 detection channels. Single spectra can be taken every second. In routine operation the spectra are stored as 5-minute averages.Currently, the UV spectroradiometer is in the NDSC research mode. Since Ny-Alesund is a primary NDSC site and Neumayer station a complementary NDSC site, it is also desirable for the measurements of spectral UV irradiance to comply with the NDSC spectral UV specifications. Thus, the main focus is directed to the characterization of the instrument and its performance.Procedures for quality control have been developed and applied to check the data quality. At the Arctic site in Ny-Alesund, the UV spectroradiometer is returned every winter to the home laboratory in Bremerhaven, Germany, for recalibration. Until 2004, the recalibration was performed in the radiation laboratory with a 1000 W FEL lamp traceable to PTB. In 2005 the main standard has been replaced by a horizontal DXW lamp, also traceable to PTB. This change in lamp type was necessary due to the design of the instrument. The instruments at the two Antarctic sites, Neumayer and Dallmann, are also exchanged on a regular basis for recalibration. During ...