Update on UV Irradiance Levels

This page gives an overview of UV levels measured recently at NSF network locations. It is updated frequently and allows tracking changes in surface UV irradiance resulting, for example, from the progress of the austral spring "ozone hole".

All data and graphs presented are preliminary, and investigators are cautioned that data are subject to revision as more rigorous quality control is applied. To obtain fully quality controlled data from previous years, please go here.

Resources for tracking the ozone hole

• NASA's Ozone Hole Watch website
• NASA/GSFC Code 613.3 Ozone Hole Monitoring
• WMO Antarctic Ozone Bulletins
• Ozone sonde measurements at the South Pole performed by NOAA/ESRL/GMD
• SCIAMACHY, GOME and OMI total ozone data provided by ESA
• Ozone hole monitoring by NOAA-16 SBUV/2 satellite
• Ozone Bulletin from the British Antarctic Survey
• Scientific Assessment of Ozone Depletion: 2006
• Scientific Assessment of Ozone Depletion: 2002

• Antarctic Ozone Hole Returns to Near Average Levels - Improvement Noted After Last Year’s Record Breaker,
  Featured article by NOAA, 1-Nov-2007
• NASA and NOAA Announce Ozone Hole is a Double Record Breaker,
  Featured article by NASA, 19-Oct-2006
• Ozone hole matches record size of 2000,
  Article published in USA Today, 3-Oct-2006
• Chemical Cause of Antarctic Ozone Hole Discovered 20 Years Ago This Month,
  Press Release by the National Sceince Foundation
• NASA Spacecraft Measures Unusual 2005 Arctic Ozone Conditions,
  NASA Mission News, 2-Jun-2005.
• Envisat Witnesses Return Of The South Polar Ozone Hole,
  Article published in Science Daily, 2-Sep-2004.
• Effects of ozone hole,
  Article published in USA Today, 25-Jul-2004 (update).
• Agency worried about ozone hole,
  Article published in USA Today, 3-Oct-2003.
• 2003 ozone "hole" approaches, but falls short of record,
  NASA press release from September 25, 2003.
• U.N. says 'ozone hole' hits record size,
  Article published in USA Today, 17-Sep-2003.
• "Antarctic ozone hole splits in two",
  WMO press release, 1-Oct-2002.

Graphs derived from SUV measurements show noon-time measurements and are updated weekly. GUV measurements include graphs and data for a large number of action spectra and are updated at least daily (some sites are updated every minute).

1	UV Index UV Index is a unit of measure of UV levels relevant to the effects on human skin. It serves as a vehicle to raise public awareness about the potential detrimental effects on health from solar UV exposure and to alert people of the need to adopt protective measures. The UV index is defined as erythemally (CIE) weighted irradiance, expressed in the units W/m², and multiplied by 40. Graphs accessible through this page show the maximum UV Index observed on a given day. More about the UV Index can be found here.
2	Short-wave UV-B Short-wave UV-B is spectral irradiance integrated over the wavelength range 298.507 - 303.03 nm. Of the plots presented, this type is the most sensitive to changes in total column ozone.
3	UV-B UV-B is spectral irradiance integrated over the wavelength range 290 - 320 nm. UV-B levels are highly influenced by solar zenith angle and total column ozone, but are also significantly affected by variations in albedo and cloud cover.
4	DNA dose-rate DNA dose-rate is spectral irradiance weighted with the action spectrum for DNA damage. The action spectrum was suggested by R. B. Setlow in "The wavelengths in sunlight effective in producing skin cancer: a theoretical analysis", Proc. Nat. Acad. Sci., USA, Vol. 71, no. 9, pp. 3363-3366, 1974. DNA dose-rates are more affected than the UV Index by changes in total ozone.
5	Visible radiation Visible radiation is spectral irradiance integrated over the wavelength range 400 - 600 nm. Data are virtually not affected by ozone variations. Of the plots presented, this type is the most sensitive to changes in cloud cover.
6	Integrals, dose-rates Data accessible via this page include various spectral integrals and dose rates in ASCII comma-separated-value (*.CSV) file format. A complete file description is available here. The files include preliminary data that is not yet fully quality controlled. Published, quality-controlled data can be found here.
7	Daily doses Daily doses include spectral integrals and dose-rates, integrated over 24 hours. Spectral ranges and action spectra applied are the same as used in our "Database 3" (see Section 6 of our latest Network Operations report for details). Data span the whole period of network operation from the late 1980s until today. Preliminary data is labeled with the words "alpha" or "beta" in the "Volume" column. A complete file description is available here.
8	Real-time data   Graphs and data are based on GUV-511 filter radiometer and are updated at least every day (some sites are updated every minute). Data are provided in both graphical and numerical form. Data products include spectral irradiance at various wavelengths, spectral integrals, the UV Index, biologically weighted dose-rates (considering a large number of action spectra), and photosynthetically active radiation. A complete file description of data products is available here.