- Press Release
- August 15, 2022
Envisat MERIS image of the world March 2003
The global reach of the Medium Resolution Imaging Spectrometer (MERIS)
instrument on board ESA’s Envisat environmental satellite is revealed by this
image of our planet Earth as it looked in March 2003.
This is a mosaic made up of true colour images using three out of 15 MERIS
spectral bands taken from Envisat in polar orbit at an altitude of 800 km, with
data combined from around 500 separate orbital segments with the intention of
minimising cloud cover as much as possible. The image has a 1.2 km resolution
and is made up of 40,000 by 20,000 pixels, equal to 2.5 gigabytes of output data.
MERIS records surface reflectivity, and a wide variety of land surface coverings
can be discerned in this way, from ice to forest, grassland to desert. This
being early spring, much of the Northern hemisphere remains covered in snow and
ice, with snows extending far down across Russia. Comparatively small
geographical features can be clearly made out, such as the increasingly
desiccated Aral Sea in the lowlands of Central Asia, positioned east of the
In addition MERIS shows how the Earth’s oceans vary in colour almost as much as
the land. Particularly noticeable is the effect of the Gulf Stream around the
British Isles with greenish sediment and phytoplankton seeming to flare off the
coast, the distinctive water colour in the shallows of the Bahamas, and the
coral reefs off Australia. Artefacts of Envisat’s orbital passes can also be
detected around the equatorial ocean areas of the image, caused by the sun
glinting off the sea surface.
GAEL Consultant, a firm based in Champs-sur-Marne, France, prepared the image
for ESA. It was shown for the first time this week at the ESA stand at the 2003
Paris Air Show at Le Bourget.
The full-resolution image is available to be zoomed into for close-up detail by
going to ESA’s Web Map Server at
and following the link at the bottom of the page. Just form a rectangle with the
cursor to select your area of interest.
Envisat MERIS Europe mosaic
The cloud-free face of Europe in the summertime is shown by this mosaic of
true-colour land images taken by the Medium Resolution Imaging Spectrometer
(MERIS) instrument on board ESA’s Envisat environmental satellite.
The image is a composite of 85 reduced and full resolution images acquired by
MERIS in the summer of 2002, using three out of 15 MERIS spectral bands, taken
from Envisat in polar orbit at an altitude of 800 km. By representing the
arithmetic average reflectivity, it displays the range of vegetation cover
across Europe and North Africa’s land surface — including the striking green
triangle of the Nile Delta, surrounded by arid desert.
Young graduate Ana SiliÛ Calzada, a member of the ESA training programme New
Opportunities for Women, prepared this test of Level 3 product from raw Level 1
top-of-atmosphere data using the Envisat (A)ATSR and MERIS toolbox software
algorithms available to ESA Principal Investigators (PIs).
"This image is really a demonstration of what can be done with the software
tools that ESA provides," explained SiliÛ. "I basically put myself in the
situation of the user to show how scientifically useful multi-temporal data can
be generated. I think of it as a work in progress, since more detail can always
The angle of the mosaic is due to the path of Envisat’s polar orbit in relation
to the Earth. This image was shown for the first time this week at the ESA stand
at the 2003 Paris Air Show at Le Bourget.
* ESA at the 2003 Paris Air Show, le Bourget
* Envisat Results
* Envisat instruments
* Envisat Software Toolbox
* World map close-up
* Gael Consultant
[NOTE: Images supporting this article are available at