Measurements at the Mauna Loa Observatory stopped after the 2022 eruption of the Mauna Loa volcano, when lava flow crossed the access road and took out power lines to the facility. The observatory remains inaccessible by vehicle and without power from the local utility company.
Observatory staff has established limited solar power in four observatory buildings and restored approximately 33 percent of the measurements onsite, including the Global Monitoring Laboratory and Scripps critical CO2 records and other atmospheric measurements.
Media can contact: Theo Stein (303) 819-7409 (theo.stein@noaa.gov) or Karin Vergoth 303-632-6413 (karin.vergoth@noaa.gov)
Spectrally resolved solar Ultraviolet (UV) irradiance reaching the Earth’s surface. Units: Watts per square meter per nanometer. Biologically weighted irradiances are in units of Watts per square meter.
The UV spectroradiometer uses a double monochromator grating spectrometer to measure the UV spectrum between 285 nm and 450 nm with a resolution of 0.8 nm. The measurement thus includes the UVB and UVA regions, and some of the visible spectrum. The system is controlled by computer. Measurements are taken at 5 degree solar zenith angle steps throughout the day (for sza <=95 degrees), except for a 2 hour period around local solar noon when spectra are taken at 15 minute intervals. Spectra are also taken at midnight. The instrument is calibrated weekly using a mercury lamp and a 45-Watt standard lamp. An absolute calibration is performed several times per year using a 1000-Watt standard lamp powered by a precision current source.
To measure a climatology of UV radiation in an extreme environment, and to understand the causes of its variability and its sensitivity to climate change factors such as ozone depletion and global warming.
No long-term trends have been detected. However, there are large seasonal and year to year variabilities.
Changes in UV radiation are critical to our understanding of the effects of ozone depletion. In addition, UV radiation at the surface is influenced by clouds and aerosols, both of which are subject to modification due to anthropogenic influences. By carrying out measurements in pristine locations over long periods, the importance of these changes can be assessed. This is one of the aims of the Network for the Detection of Atmospheric Composition Change (NDACC). The Mauna Loa Observatory is the prime low-latitude site in this network.
This has been a very successful program. In the initial stages Dr Barry Bodhaine was the NOAA primary investigator. Numerous publications from this work have advanced our understanding of the relative importance of factors that influence UV radiation. Because of its high altitude and low latitude, the UV intensities measured at this site are among the highest recorded anywhere in the world. It is not uncommon to experience UV Index values exceeding 20 (UVI values greater than 10 are considered “extreme” at most mid latitude sites). The instrumentation and calibration procedures are continuously being improved.
Richard McKenzie (NIWA)
+64-3-4400429
Dave Hofmann (NOAA)
303-497-6966
Paul Fukumura
808-933-6965 (x223)
Dr. John E. Barnes
808-933-6965 (x222)
www.niwa.co.nz
gml.noaa.gov/grad/uv.html
July, 1995