Can upper-level SO2 be monitored using the GOES sounder?
Anthony J. Schreiner, CIMSS/Univ. of Wisconsin, Madison, WI; and T. J. Schmit, G. P. Ellrod, and F. Prata
Sulfur Dioxide (SO2) is often associated with volcanic eruptions. This is important for aviation interests, as SO2 may be helpful in confirming the presence of volcanic dust. Geostationary satellites offer a rapid refresh rate and constant viewing angle and consequently the potential to provide continuous coverage of some SO2 plumes, although there can be large satellite zenith angle limitations. The current Geostationary Operational Environmental Satellite (GOES) Imager spectrally covers neither the 7.3 μm nor the 8.5 μm regions of the absorption spectrum which are associated with SO2. The geographical coverage of the GOES Sounder is significantly smaller and offers a more coarse spatial resolution than the Imager, but does have more spectral bands. Unfortunately, the GOES Sounder instrument does not offer a spectral band which is directly located within the SO2 absorption continuum. The closest band is 7.46 μm (Band 10). It was primarily chosen for its use in the detection of mid-level moisture for atmospheric moisture retrievals. However, we will show that this band does cover part of the 7.3 µm SO2 band and should, in principle, be sensitive to upper-level SO2 The purpose of this poster is to show that given a priori knowledge of an SO2 plume location, it is possible to monitor this atmospheric component via a band difference between two “water vapor” bands of the GOES Sounder. This will be demonstrated with GOES-12 for an eruption (13-15 July 2003) of the Soufriere Hills Volcano, Montserrat, which is located in the eastern Caribbean. Over the course of three days four eruptions took place, and thus offers an opportunity to evaluate whether the GOES Sounder data can be used to monitor the extent of SO2 coverage. The existence of the SO2 “cloud” is verified using NASA AIRS, TOMS, and MODIS measurements. It should be noted that the instruments on the next generation of geostationary platforms, GOES-R, will be much better suited for detection of the upper-level SO2.
Extended Abstract (1.4M)
Poster Session 4, Environmental Applications
Tuesday, 21 September 2004, 2:30 PM-4:00 PM
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