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 6/2004, issued 11/23/04
Reporting period: 11/08/04 - 11/22/04

Synopsis:
Until 11/12/04, the ozone hole was centered at the South Pole and its size was roughly that of Antarctica, according to NASA/TOMS satellite images. UV levels at McMurdo and South Pole were similar to or slightly above the long-term mean. On 11/13/04, the ozone hole started to collapse, and UV levels at both sites rapidly decreased.

Palmer Station was outside the area of the ozone hole during the reporting period and UV levels were similar to or slightly below the long-term mean.

Ushuaia was almost not affected by the ozone hole. UV levels were somewhat above average, but no spikes in UV - as have been measured historically - were observed.

As of 11/23/04, TOMS satellite images indicate that areas with total ozone columns below 225 DU still exist. Despite the recent collapse of the ozone hole, significant enhancement in UV irradiance could still occur within the next two weeks when depleted areas move over network stations.

McMurdo Station, Antarctica:
McMurdo Station was under the ozone hole until 11/12/04, and UV levels were similar to or slightly above the long-term mean, calculated from measurements of the last 10 years. From 11/15/04 onward, total ozone was above 330 DU and UV levels were significantly below the long-term mean. Noon-time UV Indices after 11/15/04 were constant at 2.5. UV Index values as high as 6.5 have been observed during this period historically.

Palmer Station, Antarctica:
Palmer Station was outside the ozone hole area during almost the entire reporting period. UV levels compared well with the long-term mean, except for the period 11/16/04 - 11/19/04, when levels were reduced. The noon-time UV Index ranged between 1.5 (on 11/17/04) and 6. The average UV Index for this part of the year is 4, but Indices as high as 12 have been observed historically, when the ozone hole was centered over Palmer Station.

South Pole, Antarctica:
South Pole was under the ozone hole until 11/15/04, and UV levels were above average. When the ozone hole broke up, UV levels decreased substantially. For example, the UV Index changed from 2.3. on 11/13/04 to 1.3 on 11/17/04.

Ushuaia, Argentina:
Ushuaia was outside the ozone hole area during the reporting period. The noon-time UV Index ranged between 3 and 7. The average UV Index for this part of the year is 5, but Indices as high as 10 have been observed historically, when Ushuaia was affected by the ozone hole.

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