As Meteosat-8 heads into retirement, we take a look back at some memorable moments captured by the first Meteosat Second Generation satellite.
05 July 2022
30 June 2022
New RGB products
The arrival of the new Meteosat Second Generation satellite, Meteosat-8, heralded a new range of RGBs from a geostationary orbit. Prior to Meteosat-8, RGBs had only come from older instruments, such as MODIS and AVHRR.
Below are some early case studies using Meteosat-8 RGBs.
Snow over the Alps and Central Europe
One of the first weather events monitored by Meteosat-8 was the cold and snowy February in 2003.
After several days of snowfall at the beginning of the month, a persistent high pressure system resulted in cold and very dry weather conditions over Central Europe for about three weeks. Large parts of Europe were snow covered, which could be seen in Meteosat-8 images from the end of the month (Figure 1 and 2).
Night-time fog and fire monitoring in South Africa
In July 2003 Meteosat-8 satellite imagery helped improve forecasting of fog by the South African Weather Service. South Africa's largest international airport (Johannesburg International Airport) frequently experiences delays in flights due to the reduction in visibility caused by fog.
The RGB IR12.0–IR10.8, IR10.8–IR3.9, IR10.8 loop (Figure 3) provided an excellent means of indicating low stratus cloud, or fog, at night which appears bright green in this colour composite. This is a result of the emissivity of water clouds in IR3.9 being much lower than in IR10.8.
Meteosat First Generation v Meteosat Second Generation
Although data from Meteosat First Generation (MFG) satellites was extremely useful, Meteosat Second Generation (MSG) offered much more — higher resolution and more information on the cloud structure and constitution – which meant forecasters had more information on the dynamics of the storms and how they will evolve.
Meteosat-6 (MFG) — Severe storms in Central Europe
On 18 May 2002, a short-wave trough approached Germany from the west. The associated cold front extended from the UK to Switzerland.
On 20 May 2003, Meteosat-8 observed rapidly growing convective storms over north west Italy.
This was best observed in the channel 04 (IR3.9) minus channel 09 (IR10.8) brightness temperature difference image, which indicates very large positive values for very cold clouds with small ice particles.
Two thunderstorm clouds with above-anvil plumes were observed in satellite imagery over northern Italy in the morning and afternoon of 6 July 2010. The development of the convective clouds on the Meteosat-8 rapid scan (five-min) imagery.
In the Meteosat-8 animation, from 15 January 2022 12:00 UTC to 16 January 11:30 UTC (15-minute time-steps), thanks to the eastern satellite position, the shock wave from the eruption of the Hunga Tonga-Hunga Ha-apai volcano can be very clearly seen travelling from west Australia over the Indian Ocean, and from the south after passing over Antarctica.
The majority of cases on the website have been written by EUMETSAT trainers. They use satellite data on a daily basis to help train others in the best way to exploit it. Retired trainers Jose Prieto and HansPeter Roesli were among the first to use Meteosat-8 data, here they discuss how they worked with the new generation of data.
"The second generation of Meteosat supplied colour to the satellite meteorology. With much better resolution than its predecessor, Meteosat-8 produced imagery in 12 channels, compared with just three of the previous generation. This technical step in spectral resolution gave way to colour in the products, in particular through RGB composites, which merge three different grey images in a coloured result.
"RGB images are not just a combination of three wavelengths. Because channels are roughly similar to each other, in particular when in the same spectral region, it is more efficient to use channel differences in the RGB choice, better than individual channels. A well-known result of this technique is the Airmass RGB, which signals Meteosat-8's ability to identify humid or ascent areas in the middle troposphere. The Dust RGB, based on the infrared window channels, depicts areas of dry aerosol in the low atmosphere, also when it travels through the Atlantic towards the Caribbean, as many of our cases studies illustrate.
"Whether meteorite debris, sonic waves created by big eruptions, pollen clouds, volcanic ash, or severe convection signs in the upper cloud, imagery from Meteosat-8 has deeply changed our understanding of meteorology and the delicate balance in the atmosphere, the Earth skin.
"Another novel aspect of Meteosat-8 was the possibility for thousands of amateurs and institutes not precisely of meteorological nature, of receiving the data via simple receivers and manageable antennas. This unforeseen development caused an unusual interest in Meteosat imagery, not just for weather applications, but also for the soil monitoring, ocean surface monitoring, and even chemistry, in particular in Brazil. Even if the field of view of a geostationary satellite is given by the nominal location of the satellite in the equatorial ring, users learnt that the actual limits of Meteosat on the western edge reached the Pacific waters off the coast of Chile and allowed for observations of volcanic eruptions in the Andes, at a time when the current generation of GOES was still under preparation."
"The multispectral coverage from the IODC position over the southern tip of Somalia benefited a region from east Africa/Europe to the longitude of the Bay of Bengal, including the Arabian and Indian subcontinents, as well as the whole Indian Ocean. This allowed for the investigation of phenomena that earlier on were marginally covered by the SEVIRI mission at 0° longitude(the coverage from 0° does not reach beyond the longitude from the Persian/Arabian Gulf to Madagascar). Thus, Meteosat-8 at the IODC position spawned numerous case studies and discussions using SEVIRI-based RGBs and the HRV band."
The Natural Colour RGB of Indian smog fanning out on both sides of the subcontinent (Figure 16), illustrates how far east the Indian Ocean Data Coverage (IODC) reaches.
As well as those mentioned above, phenomena HansPeter has seen includes a mud volcano buried in the Caspian Sea ejected a dirty plume as shown in heavily zoomed NIR image (Figure 17).