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Latest UV Irradiance Measurements

This page provides UV data measured recently in San Diego, CA; Barrow, AK; and Summit, Greenland. Data are current up to the previous week (SUV measurements) or previous minute (GUV measurements).

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.

Select data product:

Real-time data from the austral sites are no longer provided, but may be available in the future from NOAA's Global Monitoring Division (http://www.esrl.noaa.gov/gmd/grad/antuv/). Please read this document to learn why we no longer distribute real-time data from these sites.

Austral Boreal
 SUV Measurements
UV Index 1
Short-wave UV-B 2
UV-B 3
DNA dose-rate 4
Visible radiation 5
Integrals, dose-rates 6
Daily doses 7
 GUV Measurements
Real-time graphs 8
Real-time data 8
graphs     data       data & graphs

See the Remarks Section for further explanation of data products.

Links to topical information:
Links to external websites provided below do not imply any endorsement by Biospherical Instruments Inc or the NSF.

Resources for tracking the ozone hole

On the media

Remarks to SUV and GUV data products

SUV data were obtained from measurements of high-resolution SUV-100 and SUV-150B spectroradiometers. GUV data are based on GUV filter radiometers.

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.

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.

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.

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.

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.

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.

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.

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.


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