Natural look of the clouds
The Natural Colour Enhanced product is an RGB which utilises three SEVIRI solar channels: NIR1.6, VIS0.8 and VIS0.6. It is similar to a Natural Colour RGB product, with the difference that the ice-clouds and snow covered surfaces and clouds are not shown in typical cyan colour but in desaturated tones, i.e. in white shades, making it more natural for human perception.
Rapidly Developing Thunderstorms
Rapidly Developing Thunderstorms - Convection Warning product is a geostationary meteorological product for nowcasting applications. It is produced with the NWC-SAF Geo 2018 software package.
Cloud convection in natural color
The Convection RGB combines the brightness temperature difference (BTD) between the WV6.2 and WV7.3 channels (on red), the BTD between the IR3.9 and IR10.8 channels (on green) and the reflectance difference between the NIR1.6 and the VIS0.6 channels (on blue). Severe convective storms appear bright yellow in this color scheme because of the near zero BTD WV6.2-WV7.3 of overshooting Cb clouds (high red). The strong updrafts in these clouds produce small ice particles at cloud tops due to homogeneous freezing of cloud drops, resulting with large BTD IR3.9-IR10.8 (high green). Finally, large negative values of NIR1.6-VIS0.6 because of the large absorption at NIR1.6 by ice particles keeps the blue very low. Please note that small ice crystals of Cirrus clouds should not be confused with vigorous convection. Inferred small ice crystals that are not associated with anvils of Cb clouds must form by elevated strong updrafts, such as in high altitude orographic wave clouds.