Scientific Sponsorship Statement - (NIWA.SSS) Lauder File: WOUDC.TXT, date: 11 May 2000 National Institute of Water and Atmopsheric Research (NIWA), New Zealand UV spectral irradiances falling on a horizontal surface Sites Instruments Data Period Lauder, New Zealand UVL, UVM 1989 - Mauna Loa Observatory, Hawaii UVL, UV3 1995 - Boulder, Colorado UVL, UV4 1998 - Alice Springs, Australia UV5 2000 - Darwin, Australia UV6 2001 - General Methodology ------- ----------- The data are from scans in the spectral range 290 to 450 nm, with a nominal spectral resolution of 1 nm. Files of slit function are available for all instruments (eg see listing below). Instrument specifications and calibration procedures are as suggested in the Network for the Detection of Stratopsheric Change (NDSC, see McKenzie et al., ) In-house designed diffusers with a superior cosine response are used (see web pages: niwa.cri.nz/lauder). These are coupled to the spectrometers via multi-strand randomised quartz fibre-optic bundles, custom matched to the slit dimensions. A diode/filter combination that is sensitive to UVA radiation is mounted at the entrance slit is used to monitor intensity changes during the scan. Instruments are temperature stabilised to +/- 1 C. Calibrations are with reference to 1000 W FEL lamps calibrated by the New Zealand National Standards laboratory, or Optronics Laboratories. 1000 W calibrations are performed at least twice per year. Stability tests are performed weekly - viewing 45W quartz-halogen lamp for irradiance stability (both constant current, and feedback mode from a UVA diode are used) - viewing Hg lamp to monitor resolution and wavelength linearity stability (Liley and McKenzie, 1997) Wavelength registration for individual spectra is achieved by correlation alignment against Fraunhofer features in an extra-terrestrial reference spectrum. Generally, wavelength accuracy is better than +/-0.02 nm. Ozone is derived (sza < 80) using the method of Stamnes et al., 1991. Corrections for cosine errors are applied. For each spectrum (sza < 80) , the UVA transmission compared with clear sky irradiances is calculated. NIWA instruments have been involved in several international intercomparison campaigns, and have been found to be among the best available (eg Seckmeyer et al., 1995; Bais et al., 2000). Data Set Description: ---- --- ------------ Site(s): Lauder, New Zealand (45.0446S, 169.684E, 370m) Dec 1989.. Mauna Loa Obs, Hawaii (19.533 N, 155.57 W, 3400 m) Jul 1995.. Boulder, Co (39.99 N,105.26 W, 1800 m) Jul 1998 Alice Springs? Darwin? Measurement Quantities: Spectral irradiance on a horizontal surface (cosine weighted) of UV 290-450 nm at 1 nm resolution. Sampliong interval is 0.2 nm. Scans are taken at intervals of 5 degrees in solar zenith angle and at midday. On cloudless days "sky only" measurements are made at midday using a shadow band to obscure the direct sun. Since 1993 scans have been from sunrise to sunset (sza=95), and in addition, scans are taken at midnight. The acquisition time for a full spectrum is approximately 200 seconds for the earlier instruments (designated UVL and UVM) which scan only in the forward direction. For more recent instruments, (designated UV3, UV4, UV5, UV6, etc) each measumrent consists of a reverse scan and a forward scan, the total scan taking about 300 seconds. In all cases time stamp of the measurements is the time of scan centre in local standard time (eg at New Zealand, times are UTC + 12 hours). The data summaries include the following: 1. 290-450 nm integral 2. UVA, 315-400 nm 3. UVB, 290-315 nm 4. Erythemally weighted UV (CIE weighting 290-400 nm) 5. DNA-damaging UV 6. Generalised plant-damaging UV 7. Derived ozone (from ratio 305/340 nm intensity) 8. Calculated transmission in the UVA region 9. Cosine correction factor applied 10. Instrument parameters 11. Statistics of intensity changes during a scan 12. Clear sky flags In addition, spectral irradiances are listed (in units of uW cm-2 nm-1) for 290 to 400 nm, in steps of 0.2 nm. Contact Information: ------- ------------ PI Name: Dr. R. L. McKenzie Address: NIWA Lauder, PB 50061 Omakau, Central Otago, New Zealand Phone: +64-3-4473-411 (ext 829) FAX: +64-3-4473-348 Email: r.mckenzie@niwa.cri.nz Data Availability: ----------------- Please check with the PI before using the data in scientific publications. Reference Articles: --------- --------- Bais, A. F., B. G. Gardiner, H. Slaper, M. Blumthaler, G. Bernhard, R. L. McKenzie, A. R. Webb, G. Seckmeyer, B. Kjeldstad, et al., The SUSPEN intercomparison of ultraviolet spectroradiometers, J. Geophys. Res., 2000, submitted Feb 2000. Bodhaine, B. A., R. L. McKenzie, P. V. Johnston, D. J. Hofmann, E. G. Dutton, R. C. Schnell, J. E. Barnes, S. C. Ryan, and M. Kotkamp, New ultraviolet spectroradiometer measurements at Mauna Loa observatory, Geophys. Res. Lett., 23, 2121-2124, 1996. Bodhaine, B. A., E. G. Dutton, D. J. Hofmann, R. L. McKenzie, and P. V. Johnston, Spectral UV measurements at Mauna Loa: July 1995-July 1996, J. Geophys. Res., 102, 19,265-19,273, 1997. Grainger, R. G., R. E. Basher, and R. L. McKenzie, UV-B Robertson-Berger meter characterization and field calibration, Appl. Opt., 32, 343-349, 1993. Liley, J. B., and R. L. McKenzie, Time-dependent wavelength non-linearities in spectrometers for solar UV monitoring, in IRS '96: Current Problems in Atmospheric Radiation, University Alaska, Fairbanks, Alaska, edited by W. L. Smith and K. Stamnes, pp. 845-848, Deepak, Hampton, Va, 1997. McKenzie, R. L., W. A. Matthews, and P. V. Johnston, The relationship between erythemal UV and ozone derived from spectral irradiance measurements, Geophys. Res. Lett., 18, 2269-2272, 1991. McKenzie, R. L., P. V. Johnston, M. Kotkamp, A. Bittar, and J. D. Hamlin, Solar ultraviolet spectroradiometry in New Zealand: instrumentation and sample results from 1990, Appl. Opt., 31, 6501-6509, 1992. McKenzie, R. L., M. Kotkamp, G. Seckmeyer, R. Erb, R. Gies, and S. Toomey, First southern hemisphere intercomparison of measured solar UV spectra, Geophys. Res. Lett., 20, 2223-2226, 1993. McKenzie, R. L., UV spectral irradiance measurements in New Zealand: effects of Pinatubo volcanic aerosol, in Quadrennial Ozone Symposium, Charlottesville, Va, edited by R. D. Hudson, pp. 627-630, NASA CP-3266, Greenbelt, Md, 1994. McKenzie, R. L., P. V. Johnston, and G. Seckmeyer, UV spectro-radiometry in the network for the detection of stratospheric change (NDSC), in Solar Ultraviolet Radiation. Modelling, Measurements and Effects, Halkidiki, Greece, 1.52, edited by C. S. Zerefos and A. F. Bais, pp. 279-287, Springer-Verlag, Berlin, 1997. McKenzie, R. L., M. Kotkamp, and W. Ireland, Upwelling UV spectral irradiances and surface albedo measurements at Lauder, New Zealand, Geophys. Res. Lett., 23, 1757-1760, 1996. McKenzie, R. L., B. J. Connor, and G. E. Bodeker, Increased summertime UV observed in New Zealand in response to ozone loss, Science, 285, 1709-1711, 1999. Seckmeyer, G., B. Mayer, G. Bernhard, R. L. McKenzie, P. V. Johnston, M. Kotkamp, C. R. Booth, T. Lucas, T. Mestechkina, et al., Geographical differences in the UV measured by intercompared spectroradiometers, Geophys. Res. Lett., 22, 1889-1892, 1995. Seckmeyer, G., and R. L. McKenzie, Increased ultraviolet radiation in New Zealand (45 S) relative to Germany (48 N), Nature, 359, 135-137, 1992. Stamnes, K., J. Slusser, and M. Bowen, Derivation of total ozone abundance and cloud effects from spectral irradiance measurements, Appl. Opt., 30, 4418-4426, 1991. Zeng, J., R. McKenzie, K. Stamnes, M. Wineland, and J. Rosen, Measured UV spectra compared with discrete ordinate method simulations, J. Geophys. Res., 99, 23019-23030, 1994. Instrument Description: ---------- ------------ UVL JYDH10 system, 100 mm focal length, 1200 g/mm grating has bandpass 1.15 nm fwhm, and detection threshold of 0.001 uW cm-2 nm-1. 12-bit A/D conversion with gain switch ing of EHT to achieve full dynamic range UVM Bentham DM300 system, 2400 g/mm grating, 0.9 nm fwhm, meets NDSC bandpass spec but detection threshold of 0.0001 uW cm-2 nm-1 requires several scans.12-bit A/D conversion with gain switch ing of EHT to achieve full dynamic range UV3 Bentham DTM300 system, 2400 g/mm grating, 0.8 nm bandpass meets NDSC specs. 20-bit A/D conversion. UV4 Acton D270, 3600 g/mm grating, 0.6 nm bandpass. Meets NDSC specs. 24-bit A/D conversion. UV5 (and later) Bentham DTM300 system, 3600 g/mm grating, 0.6 nm bandpass. Meets NDSC spec. 24 bit A/D conversion. Algorithm Description: --------- ------------ Programme written in MS QuickBasic. Current version UVP25.EXE Reads file of instrument-dependent parameters Selection of cal file depends on date as specified in above file (ref McKenzie et al., 1992) Intensity calibration: Uses calibrations made with 1000W FEL lamps to form files of calibration factors at each wavelength. Wavelength calibration: Correlation alignment against Solar Fraunhofer lines non-linear wavelength errors deduced from Hg lamp scans. Expected Precision/Accuracy of Instruments: -------- ------------------ -- ----------- +/- 3% excluding uncertainty in laboratory lamp calibration see McKenzie et al., 1992. Instrument History: ---------- -------- (dates and description of significant changes in instrument or algorithm) Dec 1989. UVL Lauder (JY DH10) Observations began at Lauder Feb 1990. UVL Lauder Instrument rotated 180 degrees (azimuth 23) Oct 1990. UVL Lauder First observations with on-site calibration Jan 1992. UVL Lauder Cross calibration at Lauder (Seckmeyer) Feb 1993. UVL Lauder Cross calibration at Lauder (Seckmeyer, Roy) Jan 1993. UVM Lauder (Bentham DM300) Test obs began at Lauder Dec 1993. UVM Lauder Reliable measurements began at Lauder Jul 1994. UVL Garmisch Cross calibration in Garmisch-P, Germany Oct 1994. UVM Lauder Wavelength drive replaced. Feb 1995. UVL Lauder Albedo measurements. Last routine UVL obs at Lauder Jul 1995. UVL Hawaii Mounted in weatherproof box. Installed at MLO. Aug 1996. UVL Hawaii Testing sensitivity to rotation Jul 1995. UV3 Hawaii New instrument installed Jul 1998. UVL Boulder New diffuser and fibre optic input Sep 1999. UV4 Boulder New instrument installed The processing algorithm has undergone many revisions, which will continue. Current processing version (May 2000): uvp25.exe Notes: Measurements at Lauder are complemented by a wide range of ancillary data - ozone total column from Dobson spectrometer - ozone profiles from lidar (6-60 km) balloon (0-32 km) microwave radiometer (20-60 km) - trace gas column amounts (eg NO2, many gases with ftir spectrometer) - aerosol optical depth at 5 wavelengths - aerosol profiles measurements from backscattersondes (0-32 km, monthly) lidar (6-40 km) - broad band measurements including: YES UVB-1 RB meter SLC biometer RB meter LICOR Si diode pyranometer Global pyranometer (Kipp and Zonen) Diffuse pyranometer (Kipp and Zonen) Direct Beam pyranometer (Eppley, NIP) Pyrgeometer (Eppley) Actinic flux measurements: upward and downward J(NO2) 'sample Relative response, sample step = 0.2 nm 'Inst UVL UVL UVM UV3 UV4 'Date 1994Nov 1998MAR 1995feb 1997JUN 1999JUN 'Block 007 046 2170 442 766 'fwhm 1.15 nm 1.30 nm 0.88 nm 0.77 nm 0.60 nm 'Hgline 404 404 404 254 296 ' -10 0 0.000 0 1.4232E-04 0 -9 0 0.004 0 1.7660E-04 0 -8 0.0 0.007 0 2.3231E-04 0 -7 0.0 0.011 0 3.7174E-04 0 -6 0.012 0.048 0.004 6.4727E-04 0 -5 0.095 0.181 0.030 1.1324E-03 .01 -4 0.268 0.363 0.129 6.9697E-03 .03 -3 0.470 0.559 0.304 1.4338E-01 .11 -2 0.685 0.760 0.546 4.5280E-01 .38 -1 0.893 0.937 0.808 7.8608E-01 .73 0 1 1 1 1 1 1 0.886 0.900 0.817 8.7959E-01 .73 2 0.688 0.732 0.550 5.0735E-01 .35 3 0.473 0.528 0.263 1.6551E-01 .08 4 0.272 0.279 0.058 2.7989E-02 .03 5 0.091 0.096 0 1.9995E-03 .01 6 0.014 0.031 0 7.4801E-04 0 7 0 0.013 0 4.0587E-04 0 8 0 0.007 0 1.5457E-04 0 9 0 0.004 0 3.6141E-05 0 10 0 0.000 0 2.4461E-06 0