November 27, 2007
Special Feature: High UV levels and good air quality in South Africa
It is a good thing the delegations at the GEOSS conference will be in those conference rooms all day, since the ultraviolet radiation index is predicted to be high. But first, a little on the air quality in South Africa on Tuesday as part of our special series this week.
Tuesday was clear over Cape Town and western South Africa, as seen in the MODIS image on the left. The eastern part of the country was also clear, except for dense cloud cover over the coastal regions (MODIS image on the right). There were some increased concentrations of NO2 near Johannesburg according to the Ozone Monitoring Instrument (OMI is a joint ESA/NASA and
Netherlands/KNMI sensor on the Aura satellite), which I expect will continue.
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All that sunshine comes at a cost -- increased ultraviolet (UV) radiation. In addition to air quality data, satellite and ground-based Earth monitoring instruments can also measure UV radiation levels. The UV index is a measure related to how harmful the UV levels are to humans and other life. UV index values over 8 are considered to present a "very high" risk of harm; values over 11 are "extremely high" risk. The TEMIS site provided a global UV index map (below) from the SCIAMACHY instrument (run by KNMI and ESA) that showed UV index in South Africa on Tuesday to be well over 11. The UV forecast is for those high levels of UV to continue all week.
So, while the air quality may be good, be careful of the sun! Clear skies and good air quality expected to continue over much of the country tomorrow.
Posted by Jill Engel-Cox at November 27, 2007 11:51 PM | TrackBack