This page shows IASI SO2 total vertical columns for enhanced SO2 events as reported by the Support to Aviation Control Service (SACS, Each point in the figures below corresponds to a single event, as reported by SACS. The indicated vertical column value is the average of all measurements contributing to the alert, above a threshold value in Brightness temperature. The applied threshold value is Bt > 2.

The circles represent IASI data from MetOp-A; Squares are from IASI on MetOp-B. The coloured symbols (if any) are data from the current month, and colours match between map and graph. For earlier data, symbols are in black, but when hovering the mouse cursor over a point in the graph, the region where the event occurred is highlighted in the map. More detailed information can be found in Chapter 2 of the Quality Assessment Manual: (link to pdf TBD).