Previous UV Bulletin

UV bulletins are short reports on current UV levels at NSF network locations. They are posted bi-weekly between September and December when the "ozone hole" is affecting UV levels at our Austral sites.

Bulletin 4/2003, issued 10/28/03
Reporting period: 10/13/03 - 10/26/03

Synopsis:
UV levels at Antarctic network sites and Ushuaia were below the long-term means of these sites. Particularly low UV levels were measured at Palmer between 10/13/03 and 10/22/03. During this period, UV Index values were less than half of the long-term mean, calculated from measurements of the years 1991 - 2002. The comparatively low UV levels can be explained by the fact that McMurdo Station, Palmer Station, and Ushuaia were outside the area of the ozone hole during most days of the reporting period.

McMurdo Station, Antarctica:
UV levels measured at McMurdo were below the long-term mean as McMurdo was only on two days (10/14/03 and 10/19/03) underneath the ozone hole (defined by total column ozone below 220 DU). The maximum daily UV Index was 2.3. The highest UV Index historically observed during the reporting period was 5, and was measured on 10/25/97.

Palmer Station, Antarctica:
UV levels measured at Palmer Station were below the long-term mean for most of the reporting period, as Palmer was only on one day (10/13/03) underneath the ozone hole. The maximum daily UV Index was below 3 for 9 out of 14 days; the highest UV Index, measured on 10/23/03, was 6.0. The long-term average UV Index is 5.1. The overall maximum Index value for late October is 11.3, and was measured on 10/26/93.

South Pole, Antarctica:
South Pole was under the ozone hole during the entire reporting period. However, the center of the hole was displaced toward to the side of Antarctica that is facing Africa, and maximum ozone depletion was therefore observed at places away from the South Pole. UV levels remained small in absolute terms as solar elevations were still below 12.5 degrees. UV levels also remained somewhat below the long-term mean. The maximum UV Index was 0.9. Long-term mean and maximum UV Index for this period are 0.8 and 1.6, respectively. Typical summer values range between 2 and 3, with extreme value exceeding 3.5.

Ushuaia, Argentina:
Ushuaia was located outside the area of the ozone hole during the entire period. UV levels were somewhat below the long-term mean, with maximum daily UV Index values ranging between 3 and 5. One exception is 10/15/03, when the UV Index was reduced to 0.8 due to heavy cloud cover. The highest UV Index value historically observed during the reporting period was 11.7. This value was measured on 10/18/00 when Ushuaia was under the ozone hole. The value also marks the overall record UV Index measured by the NSF spectroradiometer at Ushuaia.

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