Satellite image of the month

August 2023 - Wildfires in Greece

22 August 2023

July and August 2023 saw a large number of wildfires in Greece, across many parts of the Greek mainland and also on several islands. The images above are taken from one of the most notable days, when smoke from a huge fire near the north-eastern Greek port of Alexandroupoli (reported as being the largest wildfire ever recorded in the EU) covered large areas of Greece, the Aegean and the central Mediterranean.

The images above, captured on 22 August 2023, come from the NOAA/NASA Suomi-NPP satellite, a polar-orbiting satellite which collects data while circling the Earth passing over the north and south poles. The upper image, created from the VIIRS instrument on this satellite, is a true colour image showing that thick smoke plumes (seen as a sandy light brown colour) from the Alexandroupoli fire have covered the northern Aegean Sea and spread across northern Greece and out over the Mediterranean to the west. It is also possible to see smaller smoke plumes emanating from fires near Athens, to the north of the Gulf of Corinth, and also in north-west Turkey.

The lower image, a false-colour composite that uses three near-infrared channels on the same instrument, shows the thermal anomalies associated with all of the above-mentioned fires, with the yellow colours indicating the hottest areas associated with the most severe concurrent burning conditions.

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

 

July 2023 - Tropical cyclone Khanun

31 July 2023

Khanun was a powerful, long-lived tropical cyclone that moved slowly and erratically across Japan's Ryukyu Islands and up the east coast of Korea in early August 2023, causing widespread disruption in both countries. The above image, a true-colour composite from JMA's Himawari-9 satellite, was captured on 31 July 2023, relatively early in the lifetime of the cyclone, when it was still situated well to the south of the Ryukyu Islands and its wind speeds were near their peak, the equivalent of a Category 4 Atlantic hurricane.

Credits: Image: © Crown copyright, Met Office, Data: JMA.

 

June 2023 - Cumulus clouds, Canadian wild-fire smoke and a phytoplankton bloom

29 June 2023

This image comes from the VIIRS (Visible Infrared Imaging Radiometer Suite) instrument on the NOAA/NASA NPP satellite, and shows a true-colour visible picture of the United Kingdom around the middle of the day on 29 June 2023. An active cold front had moved southeastwards overnight, bringing spells of heavy rain to many southern and eastern parts of England. Once the front had passed through, most UK areas experienced cooler, clearer conditions, and the widespread areas of shallow cumulus clouds seen in the image above allowed sunny spells for most, although some showers remained in central and western Scotland for much of the day.

Behind the cold front, stretching from just north of the Britanny Peninsula, across South-East England and into the North Sea above East Anglia (and indicated by the letter S in the image), a plume of smoke from the recent Canadian wild-fires can be seen, after having made its way across the Atlantic Ocean during the preceding days.

Also apparent in the image is a large area of phytoplankton bloom to the south and east of the Shetland Islands. These blooms often occur in the shallow waters of the North Sea at this time of year as sunlight levels increase, the warm ocean temperatures helping these microscopic marine algae to synthesise their own food via chlorophyll, and forming dazzling turquoise displays visible to satellites.

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

 

May 2023 - First pictures from MTG-I1 Flexible Combined Imager

18 March 2023

The images above give an exciting first glimpse of the capabilities of the Meteosat Third Generation (MTG) mission, after they were revealed to the public by Europe’s meteorological satellite agency (EUMETSAT) and the European Space Agency (ESA) for the first time on 4 May 2023. The first satellite in the new generation of European weather satellites, MTG-I1 was launched on 13 December 2022, and its data will be disseminated to meteorological services in Europe and beyond by the end of 2023 for operational use in weather forecasting and elsewhere. The top picture shows a true-colour, full Earth disc image captured by MTG-I1's Flexible Combined Imager (FCI) instrument on 18 March 2023. The lower image shows higher-resolution data from the same view, centred over the central Mediterranean. It demonstrates the FCI's greatly improved ability to capture crisp details such as wave clouds over eastern Libya, snow cover on the Alps, and sediment in the shallow waters along the coast of Italy, all features which are not as clearly visible, or not visible at all, in imagery from the current Meteosat Second Generation instrumentation.

With greater resolution and improved frequency of imagery received from MTG-I1, our meteorologists will be able to better monitor rapidly-developing weather conditions as they unfold. This first MTG satellite will be joined by two further satellites in the coming years. This will give a three-satellite constellation bringing huge benefit to weather forecasting, providing situational awareness, and bringing revolutionary new data from geostationary orbit for nowcasting and NWP.

Credits: MTG-I1 FCI data processed and visualised by ESA and EUMETSAT.

 

April 2023 - Fires over Southeast Asia

7 April 2023

The picture above shows a true-colour image of Southeast Asia on 7 April 2023, where hundreds of fires, scattered across Myanmar, Thailand, Laos and Vietnam, caused thick grey clouds of smoke to blanket much of the region. In this image, Laos is seen to be particularly badly affected. At this time of year near the end of the dry season, most of these fires would have been lit for agricultural and land management purposes, but in this instance they intensified and spread to such an extent that the resulting air pollution posed a major threat of the health of humans and animals across much of the region.

The image comes from OLCI (the Ocean and Land Colour Instrument) on the Copernicus Sentinel-3A satellite, a polar-orbiting satellite which collects data while circling the Earth in an orbit passing over the north and south poles.

Credits: Copernicus Sentinel-3 OLCI data, processed by the Sentinel Hub.

 

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.