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 2/2003, issued 9/30/03
Reporting period: 9/15/03 - 9/28/03 (9/15/03 - 9/29/03 for Ushuaia).

Synopsis:
Prevailing solar elevations over Antarctica are still small, and so are UV levels. Data from the last two weeks were within the range of measurements of the last years, with the exception of 2002. The early break-up of the ozone hole in September 2002 lead to unusually low UV levels. Measurements from the period 9/22/03 - 9/28/03 were more than a factor of two higher compared to data from the same period of 2002.

Recent measurements at Ushuaia were within the range of previous years, except for 9/20/03 and the period 9/27/03 - 9/29/03 when the edge of the ozone hole was above Ushuaia. The UV Index increased from 3.3 on 9/26/03 to 5.8 on 9/29/03. The latter value is abnormally high for Ushuaia for this part of the year.

McMurdo Station, Antarctica:
UV levels measured at McMurdo during the last two weeks were within the range of previous years, with the exception of 2002. During this part of the season, noon-time solar elevations at McMurdo are still below 14 degrees, and UV levels were therefore comparatively small. The largest UV Index measured during the last two weeks was 1.0, which is considerably higher than corresponding values from last year: the average daily maximum UV Index from the period 9/22/03 - 9/28/03 was a factor of 2.3 larger than the average value from the same period in 2002. Typical summer UV Index values range between 5 and 7.

Palmer Station, Antarctica:
UV levels measured at Palmer during the last two weeks were within the range of previous year, with the exception of 2002. Measurements between 9/23/03 and 9/28/03 approached, but did not exceed, the upper envelope formed by measurements of the years 1990 - 2001. The highest UV Index measured during this period was 4.7, which is over a factor of two higher than Index values of the last year. Typical summer values range between 6 and 9. Index values above 13 have been observed in November 1997 and December 1998 when the ozone hole was located above the station.

South Pole, Antarctica:
The solar elevation at the South Pole is still below 3 degrees. UV levels are therefore still low; the maximum UV Index measured in Spetember 2003 was 0.1. Typical summer values range between 2 and 3, with extreme value exceeding 3.5.

Ushuaia, Argentina:
Ushuaia is usually located outside the area of the ozone hole but can see sudden increases in UV when the edge of the ozone hole moves over the city. This happened on 9/20/03 and between 9/27/03 - 9/29/03. UV clearly spiked during these episodes. For example, the UV Index increased from 3.3 on 9/26/03 to 5.8 on 9/29/03. The UV Index typically ranges between 2.5 and 4 during this part of the year. Typical summer values range between 7 and 8, but Index values above 11 have historically been observed.

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