MERIS (left) and AATSR (below left) false colour images of the eruption on 6 June 2011. AATSR has a small swath width so its approximate location is indicated on the MERIS image by red lines. These instruments are carried on the ENVISAT platform.

The area of the AATSR image identified as ash is shown in the figure below right. AATSR provides two near-simultaneous views of the Earth, the first looking "forward" along the satellite track at 55 degrees from the vertical, the second looking at nadir. Ash identified from the forward view appears green in the image below, detection in the nadir view is shown as red, and detection in both views appears yellow. There is clear parallax (due to the height of the ash cloud above the ground) apparent in this image, which makes determination of the plume height possible. In addition to the main ash plume, to the south there is an extensive area of much thinner ash.

Credit Dr Gareth Thomas.

The image on the left gives the height of the plume using a stereo matching technique. The images covers the same area as the AATSR images above but with a different aspect ratio. The main plume appears at about 15 km but descends to about 12 km quite quickly. The plume to the south is much lower - typically around 5 km in altitude.

Credit Dr Gareth Thomas.

The image on the left give SO₂ amount and altitude determined from IASI measurements on the 6 June 2011. The SO₂ is colloced with the ash plume measured by AATSR suggesting that both gas and ash were injected at similar altitudes.

Credit Dr Elisa Carboni.

SO₂ amount and altitude over South America and the South Atlantic.

Credit Dr Elisa Carboni.

SO₂ amount and altitude as the SO₂ plume disperses through the Southern Hemisphere.

Credit Dr Elisa Carboni.