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 5/2006, issued 11/27/06
Reporting period: 11/9/06 - 11/27/06

Synopsis:
The ozone hole had an elongated shape between 11/11/06 and 11/19/06 and its edge reached the tip of South America on 11/14/06 and 11/15/06. UV levels at Palmer Station and Ushuaia were very high during this period; the maximum daily UV Index ranged between 8 and 10 at both sites. UV intensities at the South were above the long-term mean for the entire reporting period. UV levels at McMurdo were mostly moderate.

Large areas with total ozone below 220 DU still exist at this time. With the Sun now relatively high in the sky, we expect large increases in UV irradiance within the next two weeks if ozone depleted air masses move over network sites.

McMurdo Station, Antarctica:
McMurdo Station was close to the edge of the ozone hole during most of the reporting period. Total ozone varied between 160 and 320 DU, according to GUV measurements. UV levels varied within the limits of measurements from the last 16 years. The maximum daily UV Index ranged from 3.2 to 5.7; the average was 4.4.

Palmer Station, Antarctica:
Total ozone at Palmer Station was below 260 DU during the periods 11/12/06-11/17/06 and 11/25/06-11/27/06. Between 11/14/06 and 11/16/06, total ozone dropped to values between 190 and 210 DU. UV intensities spiked conspicuously during these three days. For example, the maximum daily UV Index increased from 5.6 on 11/13/06 to 9.8 on 11/15/06. UV levels were moderate (maximum daily UV Index between 2 and 5) during the remainder of the reporting period.

South Pole, Antarctica:
South Pole Station was affected by the ozone hole during the entire reporting period. UV levels were above the long-term average, calculated from measurements of the last 16 years. Between 11/9/06 and 11/19/06, intensities were close the upper limit of historic measurements. The UV Index increased from 2.4 on 11/9/06 to 3.0 on 11/19/06, and fell to 2.0 on 11/22/06, in response to an increase in total ozone. Due to the low Sun at the South Pole, UV levels are generally smaller than at the Antarctic coast. However, human exposure to UV radiation is significant even for UV Indices below 3, due to radiation reflected off snow-covered ground.

Ushuaia, Argentina:
Ushuaia was located outside the area of the ozone hole during the entire period. However, on 11/14/06 and 11/15/06, total ozone dropped to values between 220 and 250 DU when the ozone hole extended up to the tip of South America. UV levels spiked on the two days: the maximum daily UV Index on 11/15/06 was 10.0. This is close to the historic maximum UV Index for late November of 10.5, which was observed on 11/13/97. UV intensities for the remainder of the reporting period varied about the long term mean with the maximum daily UV Index ranging between 3 and 7.

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