Soputan, Sulawesi, Indonesia

27 December 2005

Image Source: MODIS infrared / CO2 slicing image, 27 December 2005, 0210 UTC (scale is height above mean sea level in metres).

Comments: This was initially reported at less than 6 km amsl on the 27th by an airline pilot, and 1 km above summit height (1784 m; i.e. < 3 km amsl) by ground observers on the 28th. In post analysis we have compared the height of the plume on infrared imagery with a "CO2 slicing" image kindly provided by Michael Richards of CIMSS (University of Wisconsin). The CO2 slicing technique appears to validate the post-analysed VAAC height of ~12.5 km amsl. The appearance of the cloud on true-colour, near-infrared and infrared imagery is consistent with an ice-rich, glaciated volcanic cloud, in-line with the CVGHM account of water interactions at the ground, and also with a high water loading in the atmosphere. The extensive areas of cloud around hindered satellite detection of the eruption by the VAAC until after the pilot report of the eruption had been received.

Reference for CO2 slicing::

Richards, M. S., Ackerman, S. A., Pavolonis, M. J., Feltz, W. F., and Tupper, A. C. (2006) Volcanic Ash Cloud Heights Using the MODIS CO 2 -Slicing Algorithm. AMS 12 th conference on aerospace and range meteorology, Atlanta , Georgia USA, 2006, http://ams.confex.com/ams/pdfpapers/104055.pdf

18 October 2004

Image Source: GOES-9, reverse absorption, 18 October 2004, 0225 UTC / 0925 UTC.

Comments: Volcanic lightning, ashfall, lava and pyroclastic flows accompanied the eruption. The cloud reached an altitude of 5-6 km, where it was prevented from rising further by an atmospheric temperature inversion.

1 September 2003

Image Source: Terra MODIS, 1 September 2003, 0210 UTC

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