The U.S. government is closed. This site will not be updated; however, NOAA websites and social media channels necessary to protect lives and property will be maintained.

To learn more, visit commerce.gov.

For the latest forecasts and critical weather information, visit weather.gov.

Total Ozone



The Dobson Ozone Spectrophotometer has been used to study total ozone since its development in the 1920's. The observations of total ozone, the total amount of ozone in a column from the surface to the edge of the atmosphere, by this instrument is one of the longest geophysical measurements series (at Arosa, Switzerland) in existence.


Dobson spectrophotometer. Click to view full size image

Today, the instrument is an important part of a global effort to understand the role of stratospheric ozone in atmospheric chemistry, biological and ecological effects of solar UV radiation, climate and weather. GML maintains 15 stations which use the Dobson Ozone spectrophotometer for total ozone measurements.

GML hosts the World Meteorological Organization (WMO), Global Atmosphere Watch World Dobson Calibration Center. GML is the custodian of the Dobson World standard instrument D083, which is calibrated at the GML Mauna Loa observatory every two years using the Langley Technique. Dobson regional standards are calibrated to D083 approximately every four years (http://www.o3soft.eu/dobsonweb/calibrations.html). US regional network instruments are also calibrated to D083 at GML headquarters in Boulder, Colorado. Please Contact Glen McConville for additional information.

Operations Handbook - Ozone Observations with a Dobson Spectrophotometer

GML Dobson Recent Data Plots

GML Dobson observation sites

Dobson Troubleshooting Guides

Total Ozone Contacts