# Sandwich products - satellite imagery visualisation technique

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## Chapter VII: Further examples

- Further examples

### Further examples

It is recommended to use rapid scan animations to take a closer look at storm tops and storm development. In sandwich animations one can easily recognise storm top features indicating possible severity, like:

- Many intensively pulsing overshooting tops
- Long-lived overshooting tops
- Intense gravity waves:
  - Concentric waves
  - Radial cirrus
  - Ship waves
- Above-anvil ice plume
- Long-lived cold ring (more than 40 minutes)
- Long-lived cold U/V (more than 40 minutes)

These all are indicators of possible storm severity, as the common mechanism of these features is the intense updraft. The following images show examples of these cloud top features.

Figure 7.1: Overshooting top and cold ring in Meteosat SEVIRI HRV/IR10.8 blended images, taken on 14 June 2010 at 10:55 UTC (left) and 8 July 2015 at 14:05 UTC (right) over Hungary. (Processed at OMSZ with the ImageMagick script using the 200-240 K BT region for the colour enhancement.)

Figure 7.2: Storm with cold ring and overshooting top in centre of the cold ring east of Vietnam coast, Terra MODIS image, taken on 28 October 2016 at 03:10 UTC. Sandwich product created from band 01 and colour-enhanced band 31 (BT 183-203K). (Courtesy of Martin Setvák, CHMI)

Figure 7.3: Multiple overshooting tops on the top of a storm above south-east Nigeria. Aqua MODIS image taken on 18 May 2013 at 13:09 UTC. Sandwich image is created from the 250 m band 01 and colour-enhanced 1 km band 31 (11 μm) BT images. (Courtesy of Martin Setvák, CHMI)

Figure 7.4: Overshooting tops, ice plume, gravity waves and cold rings in Aqua MODIS sandwich product based on True Colour RGB and colour-enhanced band 31 image, taken on 2 August 2008 at 12:15 UTC over Slovenia. (Courtesy of Martin Setvák, CHMI)

Figure 7.5: Above-anvil ice plumes in Meteosat SEVIRI HRV/IR10.8 blended image over Slovakia, taken on 19 July 2011 at 16:45 UTC (left), and over Hungary, taken on 9 June 2012 at 17:33 UTC. (Processed at OMSZ with the ImageMagick script using 200-240 K BT region for the colour enhancement.)

Figure 7.6: Above-anvil ice plume in Terra MODIS blended image over Gulf of Bengal, taken on 25 August 2003 at 05:20 UTC. (Courtesy of Martin Setvák, CHMI)

Figure 7.7: Above-anvil ice plume, gravity waves and overshooting tops in Meteosat SEVIRI HRV/IR10.8 blended image, taken on 18 August 2011 over Belgium. (Processed at OMSZ with the ImageMagick script using 205-245 K BT region for the colour enhancement.)

Figs. 7.8-7.13 show examples of different types of gravity waves

Figure 7.8: Radial cirrus and gravity waves over a storm top above the Czech Republic in Meteosat SEVIRI HRV/IR10.8 blended image, taken on 13 July 2011 at 18:35 UTC. (Courtesy of Martin Setvák, CHMI)

Figure 7.9: Radial cirrus, overshooting tops, cold-U and ice-plume over storm tops over Romania, Bulgaria and Hungary in Meteosat SEVIRI HRV/IR10.8 blended image, taken on 10 June 2013 at 15:40 UTC. (Processed at OMSZ with the ImageMagick script using the 200-240 K BT region for the colour enhancement.)

Animation (created from 5-minute SEVIRI HRV/IR10.8 blended images, 10 June 2013, 12:00-17:40 UTC)

Figure 7.10: Radial cirrus, overshooting tops, cold-U at storm tops over Romania, Bulgaria, Ukraine and Hungary on Meteosat SEVIRI HRV/IR10.8 blended image, taken on 10 June 2013 at 17:00 UTC (Processed at OMSZ with the ImageMagick script using 200-240 K BT region for the colour enhancement.)

Figure 7.11: Radial cirrus, overshooting tops, cold ring and gravity waves over storm tops over Hungary, Slovakia and Ukraine, taken on 14 June 2010 at 12:55 UTC. (Processed at OMSZ with the ImageMagick script using the 205-245 K BT region for the colour enhancement.)

Animation (created from 5-minute HRV/IR10.8 blended images, 14 June 2010 10:00-17:55 UTC).

So-called 'ship-trail gravity waves' form when there is an obstacle in the stream (see Fig. 7.12). The 'obstacle' can be a ship, island, mountain, or an overshooting top of a thunderstorm. Such gravity waves on top of convective storms indicate intense updrafts and strong storm-relative wind at the storm top level.

Figure 7.12: 'Ship trail gravity waves' behind a ship (top image) and downstream of the overshooting top of a storm above South Dakota (USA) in a NOAA-15 AVHRR blended image (below), taken on 9 July 2009 at 11:35 UTC. (The satellite image is processed by Martin Setvák, CHMI)

Figure 7.13: 'Ship trail gravity waves' behind a duck (top image) and downstream of the overshooting top over the coast of Sicily in a Meteosat SEVIRI HRV/IR10.8 blended image (bottom), taken on 2 September 2010 at 16:20 UTC. (Processed at OMSZ with the ImageMagick script using the 200-240 K BT region for the colour enhancement.)