Regional And Mesoscale Meteorology Team
Daily Satellite Discussion
Tuesday September 23, 1997
Today we take another look at detecting volcanic ash plumes using multichannel GOES-8 imagery. Soufriere Hills, Montserrat continues to errupt and put out ash plumes. The imagery depicted are from 18 September 1997 at 1601 UTC. Notice the detail in the 1 km GOES-8 visible imagery, here blown up to 0.5 km (Figure 1). Extending downwind from Montserrat, we see an ash plume. We can also see a line of clouds which have formed on the edges of the wake region of the island. Similar lines of clouds are shown extending downwind from other islands in the area. The Figure 2 shows how well the ash plume is detected by the 3.9 micrometer imagery (channel 2) and multi-channel combinations. We can see the bright hot spot on Montserrat in channel 2, but it is even clearer in the reflectivity product (upper right). The ash plume is detectable in the channel 4-5 difference product (10.7-12.0 micrometer), but stands out even clearer in a new test product which combines the 3.9, 10.8 and 12.0 micrometer data.
Bernadette Connell