Development of a ozone mini-hole over the Atlantic ocean
November 8, 2001
On 8 November 2001 a region of low ozone is developing over the Atlantic ocean. The European satellite ERS-2 with the instrument GOME (Global Ozone monitoring Experiment) has detected ozone values of 216 Dobson units* over Greenland. According to the ozone forecast based on the GOME ozone data, a minimum value of 184 DU is expected to occur early this evening, see image. If this forecast turns out to be accurate, this would imply that the present event equals the record low ozone values that were measured on 30 November 1999. On that day values as low as 185 DU were recorded above Denmark. Ozone values between 260 and 320 are normal for early November.
Operational five-day ozone forecasts have recently become available. More information on the ozone forecast can be found here. According to the forecast, the low ozone region will move to Scandinavia with ozone values between 200 and 225 DU on November 10.
Ozone mini-holes over Europe are occuring regularly the last years (publication on the mini-hole of 30 November 1999). In contrast to the Antarctic ozone hole, the low ozone values are not caused by chemical reactions and CFC's. The mini-hole events last only a few days, and they are related to an unusual atmospheric flow.
The ozone layer protects our planet from potentially harmful ultraviolet sunlight. A thinning in the ozone layer results in an increase of the amount of ultra-violet radiation. At this time of the year at our latitudes, however, the sun does not rise high enough above the horizon to deliver a significant amount of harmful ultraviolet light.
* A Dobson unit is a measure of the amount of ozone above a certain place on Earth.