For more than 30 years Popocatépetl, situated south-west of Mexico City, has produced powerful explosions at irregular intervals. On 23-24 November 2017 two such short eruptions were observed.
By HansPeter Roesli (Switzerland) and Jochen Kerkmann (EUMETSAT)
The eruptions can be seen on the Airmass RGB and Ash/SO2 RGB image sequences from GOES-16’s ABI imaging radiometer.
The Ash/SO2 sequence, 23 Nov 20:00 UTC–24 Nov 08:00 UTC (MP4, 6 MB), shows the classic red to yellow-coloured plume that essentially points to ash as its main content.
The Airmass RGB animation, 23 Nov 20:00 UTC–24 Nov 08:00 UTC (MP4, 3 MB), quite surprisingly, shows a mostly neutral coloured plume and, for most of the time, lacks the pink colour that usually signals the presence of SO2 in a dry atmosphere, which was manifest here.
The two images from 23 November at 22:23 UTC (Figure 1) clearly demonstrate that beyond ash there was some SO2 involved (red arrows), at least towards the end of the first eruption.
The Near-Infrared (1.3) and the Cloud Type RGB (see recipe and interpretation (PDF, 1 MB) images (Figure 2) also show the volcanic plume very nicely (typical red colour for high, thin cloud). The fact that we see the plume in the NIR1.3 channel hints at a high cloud, at least above 5 km.
The so-called "Cloud Type RGB" was presented at the RGB workshop in Tokyo in November 2017 as one of the new RGBs that make use of newly available channels on the GOES-16 ABI. It combines three solar channels to distinguish various cloud types: the NIR1.3 band (on red) is used to detect high clouds (including very thin cirrus clouds); the VIS0.6 band is used to detect low clouds; the NIR1.6 band is used to discriminate between ice and water clouds.
Note: NOAA's GOES-16 satellite has not been declared operational and its data are preliminary and undergoing testing.
Eruptions of Popocatépetl in Mexico (CIMSS Blog)
Popocatepetl volcano news & eruption update (Volcano Discovery)
Mexico City volcano ERUPTS: Huge plume of smoke blasted into air amid fears of BIG ONE (The Express)