Weather Satellite Images: Aosta Valley
Weather satellite images (Aosta Valley) show the cloud cover. New satellite observations become available every 5 to 15 minutes, depending on the location. The images can be animated to produce a minute-by-minute satellite view of the weather. The satellite animation is a great tool to understand weather development and movement of clouds, and is often used by meteorologists for short term weather forecasting. The global satellite composite is generated from 5 different satellites (METEOSAT, GOES-16, GOES-17, HIMAWARI, METEOSAT-IODC) and processed into an Earth-colour image for better readability. The global satellite image has the maximum possible resolution as provided by the satellites, yielding an incredible 500 megapixels for the entire world.
Why are there some clouds missing at night?
During daytime the satellite can take high resolution photos of the weather using the wavelengths of visible light. But unlike your digital camera, the satellite can also take pictures at night, using infrared radiation. This thermal infrared measures the temperature of objects, and cold objects appear in a bright white. Therefore, cold clouds appear very bright while warm clouds are less visible. Low clouds, and especially fog, do sometimes have similar temperatures as the Earth’s surface and then become almost invisible to the satellite at night. As the infrared signal is much weaker than visible light, the resolution of satellite images is much less at night than during daytime.
Why can I not see my house on the satellite image?
The weather satellites need to take a picture of the entire world every 5 to 10 minutes. In order for this to work they have to be far away (at ~36'000 km altitude). At this distance your house is simply too small to be visible. The satellite image you know from e.g. Google maps was taken from only 100 km distance, but you get only a few images a year and not one every 5 minutes.