First 2.5 minute rapid scan test from Meteosat-8

By Martin Setvak (CHMI)

The animation shows a reprojected HRV view of storm cloud formations over Serbia, Romania and Bulgaria during the day (the jump is an anomaly).

These four experimental scans complement a similar test performed using Meteosat-10, during its commissioning phase, on 11–12 September 2012.

The data collected within these tests will help scientists improve their concepts of storm-top processes and better understand the complex features top of convective storms, which are observed by weather satellites. As some of the storm-top processes occur on timescales of several minutes (such as overshooting tops), shortening the observation interval shows the storm-top features in better temporal details.

The data collected on 17 May 2013 between 09:00 and 21:00 UTC by Meteosat-8, shows evolution of storms across various parts of Europe. For an overview of the weather situation and evolution of storms at different regions, see the loop in pseudo-natural colours (Figure 3); in colour-enhanced IR10.8 brightness temperature loop (Figure 4), and in the storm RGB product (Figure 5).

Among the other storms, the one above southern Bavaria has produced a magnificent show in its initial phase, ejecting huge amounts of small particles into the cloud tops. These small ice particles significantly increase the cloud-top reflectivity in the 'microphysical' bands, at 1.6 and 3.9 microns.

The Storm RGB product is set up in such a way that the high reflectivity of the cloud tops in these bands is manifested by intense yellow colours, which is what we can see in the Storm RGB loop (Figure 6) between 12:05 and 13:10 UTC. Later on though the storm is still active, it switches to a 'normal' mode, producing larger ice particles, which are represented by darker orange shades.

The prime sources of small particles at tops of the storms are storm updrafts, though several other mechanisms may contribute as well. See also the loops of the HRV channel (loop 5) and the colour-enhanced IR10.8 channel (loop 6).