********************************************************* From: Simon Carn <scarn@xxxxxxxx> ********************************************************* The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite detected significant SO2 emissions associated with the September 30, 2007 eruption of Jebel al-Tair, Yemen. No SO2 emissions were apparent in OMI data collected at 1015UT on September 30, so we infer that the eruption started later that day. On Oct 1 at 1100UT a large SO2 cloud was observed NW of the volcano over NE Sudan and the Red Sea, with a plume of SO2 emanating from the island indicating continuing activity. The total SO2 burden measured by OMI at this time was ~70 kilotons. Subsequently, only very weak SO2 emissions have been detected near the volcano, suggesting that the eruption has waned. However, the SO2 cloud observed on October 1 has continued to drift across the Arabian Peninsula and central Asia, and on October 5 the leading edge of the cloud reached Japan. The precise altitude of the SO2 cloud is currently unknown, but the speed and pattern of its dispersion, coupled with a relatively slow decrease in SO2 burden, imply that it is being transported by the subtropical jet stream at an altitude of at least 10 km. We hope to have confirmation of the altitude when data from the CALIPSO space-borne lidar instrument become available. The high altitude reached by the cloud suggests an energetic eruption with high lava effusion rates in the early stages of the event. Images of the SO2 cloud are being posted on the OMI SO2 group website (http://so2.umbc.edu/omi). There are also some nice photos of the eruption and the island here: http://www.nato.int/multi/2007/071001a-volcano/photos/index.html#1 Best regards, Simon Carn [ simon carn | joint center for earth systems technology ] [ umbc | 1000 hilltop circle | baltimore | md 21250 | usa ] [ 410-455-1454 | 410-455-5868 (fax) ] [ www.volcarno.com | so2.umbc.edu ] ============================================================== To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxxx To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ==============================================================
