First Images from POLDER
(Resolution is about 6x7 km)
THE FIRST POLDER IMAGE OVER FRANCE
September 16,1996 received Place:Japan
This view is the very first image acquired by POLDER onboard ADEOS over
France on September 16th 1996.
It is a blue, green and red color composite of POLDER measurements at 443
nm, 670 nm and 865 nm.
Marked differences appear between the clouds (in white) and
different types
of surfaces: vegetation in red, soil in brown and yellow, sea in dark
blue.
The bright spot in the Mediterranean sea, West of Sardaigne, is the sunglint
pattern.
More than 15000 such images are taken every day by POLDER on ADEOS providing
a daily global coverage of the Earth in eight spectral channels of the
visible and near infrared spectrum.
THE FIRST IMAGES ACQUIRED BY POLDER OVER FRANCE
September 16,1996 received Place:Japan
POLDER acquires images through eight spectral filters in the visible and
near infrared spectrum and also through polarizers.
This pair of images shows the same September 16th 1996 first acquisition
over France in natural light (left image) and polarized light (right image).
Each image is a blue, green and red color composite of POLDER measurements
at 443 nm, 670 nm and 865 nm.
On the conventional image (left), marked differences appear
between the
clouds (in white) and different types of surfaces: vegetation in red, soil
in brown and yellow, sea in dark blue. The bright spot in the Mediterranean
Sea, west of the island of Sardinia, is the sunglint pattern.
On the polarized image (right) the color blue prevails and the
geographic
contours can hardly be recognized. This is because the polarized light
mainly results from scattering in the atmosphere which increases at shorter
wavelengths.
The clouds still appear in grey or white and the sunglint spot in the
Mediterranean Sea corresponds to a strong polarized signal.
The additional information provided by these original polarized measurements
allows a better characterization of the atmospheric contribution to the
signal measured at the top of the atmosphere, and thus an improvement in the
determination of both surface and cloud parameters of interest.
FIRST SEQUENCE OF POLDER IMAGES OVER EUROPE AND NORTH
AFRICA
September 16,1996 received Place:Japan
This is the first sequence (top to bottom and left to right) of images taken
by POLDER onboard ADEOS on September 16th. Each image is a blue, green and
red color composite of POLDER measurements at 443 nm, 670 nm and 865 nm.
Marked differences appear between the clouds (in white) and
different types
of surfaces: vegetation in red, soil in brown and yellow, sea in dark
blue.
An examination of the same area followed from one image to the other shows
large variations in intensity. In the Mediterranean Sea a bright spot
corresponding to sunglint appears west of Corsica and moves southwards
before disappearing near the African coast (images 1 to 3).
Owing to its wide field of view POLDER can take images of a single target
successively from different viewing angles. This unique capacity allows the
directional properties of the radiation reflected by land surfaces and
clouds to be characterized and studied.
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