Satellite image of the month

March 2023 - Spring equinox

21 March 2023

This image was taken from Meteosat-11 (the European geostationary weather satellite positioned above the equator at 0 degrees longitude) at around 0600 UTC on 21 March 2023, just hours after the spring (or vernal) equinox. At this time of day, we see the Earth's eastern hemisphere illuminated by sunlight entirely, with the western hemisphere completely in darkness. This particular type of image uses a combination of channels that provides a view near to what the human eye would see, except that ice clouds show up as a cyan colour. A couple of hours after this image was taken, EUMETSAT performed an operational swap, with the Meteosat-10 satellite taking over duties for the Earth full-disc service, and Meteosat-11 being assigned to the rapid-scanning service over the northern-most portion of the Earth's disc.

Credits:  Image: © Crown copyright, Met Office; Data: EUMETSAT

 

February 2023 - Aurora Borealis

27/28 February 2023

Here are a couple of night-time images from the day-night band (DNB) of the VIIRS instrument on the NOAA/NASA Suomi NPP polar-orbiting satellite, showing the spectacular Aurora Borealis to the north of the UK on 27 and 28 February 2023 (with the Aurora being seen as the brighter green swathes in the upper portion of each image). The DNB detects relatively low light levels at night-time, and city lights, roads and oil platforms can also be seen further south. The green colouration used in this image is chosen to highlight the brighter parts of the image more effectively.

Credits:  Image: © Crown copyright, Met Office; Data: NOAA/NASA

 

January 2023 - Fog in northern Italy and snow over the Central Alps

6 January 2023

The picture above shows a true-colour image of northern Italy and the Central Alps from the morning of 6 January 2023. At the bottom of the image, we see the large, flat expanse of the Po Valley plain completely covered by fog and low cloud. We also see tendrils of fog penetrating northwards into the mountain valleys just to the north of the plain, and also over Lake Maggiore and Lake Como (labelled as M and C respectively in the image).

Also of interest is the relative lack of snow in some of the Swiss Alpine valleys further north. For example, the valleys and lower slopes adjacent to the river Vorderrhein (the Anterior Rhine, labelled as a yellow "V" in the upper portion of the image) are seen to be free of snow, an unusual occurence for this time of year.

The image comes from the Copernicus Sentinel-2A satellite, a polar-orbiting satellite which collects data while circling the Earth passing over the north and south poles. One of the images we can create from the Multi-Spectral Imager (MSI) instrument on this satellite is a true colour image, enabling us to see the land, lakes, snow, clouds and fog from space much as they would appear to the human eye.

Credits: Copernicus Sentinel-2 data, processed by the Sentinel Hub.