Large SO2 plume (in green) from Erta Ale volcano in Ethiopia crosses the Red Sea towards Yemen.
More information and detailed analysis of the feature can be found in the In Depth section.
by HansPeter Roesli and Jochen Kerkmann (EUMETSAT)
On 3 November 2008 a volcanic eruption occurred in a range of volcanoes in northern Ethiopia, called the Erta Ale range. According to the HRV channel of Meteosat-9 (see 13:00 UTC image, PNG, 106 KB) the eruption started between 12:45 UTC and 13:00 UTC and can be located in the area of the volcanic cones Alu and Dalafilla. Thirteen months earlier, on 30 September 2007, nearby Jebel Al-Tair erupted in the southern Red Sea.
More information on the eruption and the volcano range may be found on the NASA Earth Observatory website.
The initial phase of the 'Erta Ale' eruption can be well observed with the SEVIRI IR8.7 channel using the Volcanic Ash RGB product (see image below). The light-green, high-level SO2 plumes (one exposed and one hidden under cloud streaks) and the black ash plume (mixed with ice particles by this time) result from the start of the eruption. The low-level SO2 plume, on the other hand, started to be ejected only some three hours later. However, the IR8.7 channel loses its capability to detect SO2 on 4 November over the sandy soils of Yemen and Oman, while some SO2 continues to be blown from the volcano to the Red Sea (see Animation, 3 Nov 12:30 UTC–4 Nov 12:00 UTC, MPG, 5 MB).
Thanks to the presence of relatively dry air ahead of humid air, marked by extensive cloudiness over Saudi Arabia, the evolution of the high-level SO2 plume is visible on 4 and 5 November in the Meteosat-9 Airmass RGB product that uses, among other channels, the WV7.3 channel (see Animation, 3 Nov 12:30 UTC–5 Nov 12:00 UTC, MPG, 10 MB). The time sequence of the Airmass RGB shows pink coloured SO2 plumes moving from Yemen to Oman and fading by noon on 5 November. The SO2 signal (1284cm-1–1344cm-1) extracted from Metop-A IASI data over the mid-morning and early-night orbit the same day confirms the presence of SO2 (see IASI-SEVIRI comparison, PNG, 483 KB). Similarly, the SO2 product extracted from the mid-morning orbits of Metop-A GOME-2 (see SO2 Vertical Column Density products, PNG, 368 KB, source: DLR) identifies an SO2 patch in the same area.
Meteosat-9 Ash RGB Product