What does this program measure?
Two Brewer ozone / ultraviolet spectrophotometers operate continuously outdoors at MLO. The systems are controlled by desk-top computers located inside the MLO NDSC building. Spectral scans of global UV-B irradiance are made approximately three times each hour during daylight hours. The MKIII Brewer makes measurements at 0.5 nm intervals at wavelengths between 286.5 nm and 363.0 nm with a resolution of about 0.5 nm. The MKIV Brewer makes the same measurements between 290.0 nm and 325.0 nm. Direct sun total ozone measurements are made up to 80 times per day, depending on the time of year.
How does this program work?
The technique used is absorption spectroscopy of ultraviolet radiation. The Brewer ozone / ultraviolet spectrophotometer operates continuously outdoors. A sky camera is installed in the lid of the MKIV Brewer and captures a sky image every ten minutes. The Brewers and the sky camera are controlled by indoor desk-top computers with cables (100 ft.). The Brewers are visited by Meteorological Service of Canada (MSC) staff on a two-year cycle for calibration, maintenance, repairs and system upgrades.
Why is this research important?
The data will provide useful long term measurements of ozone and UV-B at the Mauna Loa site and would be available for comparison with other measurements at the NDSC site (lidar, etc.,). This research is also part of maintaining the Brewer reference in Toronto. The CURVI will also enhance the periodic extraterrestrial calibrations that MSC carries out at MLO.
Are there any trends in the data?
No significant trends observed to date.
How does this program fit into the big picture?
What is it's role in global climate change?
Comments and References
Kerr, J.B., New Methodology for deriving total ozone and other atmospheric variables from Brewer spectrophotometer direct sun spectra, J. Geophys. Res., 107, doi:10.1029/2001JD001227, 2002.
NDACC Long term Brewer Calibrations