March 20, 2007
ICESAR CAMPAIGN
PROVIDES GLIMPSE OF FUTURE SENTINEL-1 IMAGES OVER ICE
It is perhaps
fitting that at the beginning of the International Polar Year, an
ambitious
airborne campaign is now underway and realizing excellent results in
the
extreme north of Europe
in support of ESA's
Sentinel-1 mission - which amongst other application areas will
contribute to
ice monitoring.
Carrying a Synthetic Aperture Radar (SAR), the images that Sentinel-1
will
provide are particularly well suited for applications based on mapping
sea ice.
High-resolution ice charts, monitoring icebergs and forecasting ice
conditions
are examples of important application areas that are expected to
benefit greatly
from Sentinel-1, which is being developed by ESA in support of GMES
(Global
Monitoring for Environment and Security).
Developing the mission to meet the users' needs in a variety of
application
areas is of utmost importance. A major challenge for Sentinel-1 is to
ensure
that the satellite will yield data with the quality and timeliness that
users
truly need. It is not surprising therefore, that airborne campaigns
play an
important role in helping with the design of these missions as the
experiments
carried out simulate satellite data long before the actual launch of
the
mission.
"ESA
is
putting a tremendous effort into the design and implementation of the
Sentinel-1 mission," says Malcolm Davidson, Sentinel-1 Mission
Scientist.
"While this effort might be invisible to future users of Sentinel-1
products, it is critical that we validate the modes of operation and
quality of
data products ahead of launch. The IceSAR campaign is allowing us to
simulate
Sentinel-1 radar images over ice well before launch in 2011, and better
prepare
for the mission."
Now
one week
into the IceSAR campaign, a few surprises are being revealed.
Unexpectedly,
there is a lack of ice – even where the campaign is being
carried out near
Longyearbyen in Svalbard, which is way above and Arctic Circle and only 10
degrees from the North Pole.
"It
is
unusual to have so little sea ice at this time of year," commented sea
ice
expert Wolfgang Dierking from the Alfred Wegner Institute (AWI), who is
leading
a team investigating better methods of characterizing sea ice and the
impact it
has on climate. "This illustrates the importance mapping sea ice extent
and conditions from space. In addition to the operational needs for
high-resolution ice charts, in support of shipping for instance, we
know that
sea ice plays a major role in climate forecasting as it both acts as a
blanket
of insulation between the water and the atmosphere and, unlike open
water,
strongly reflects incident sunlight. Consistent information on sea ice
conditions over large areas and over long time periods are required
– which is
exactly what the Sentinel-1 mission will bring."
A
big help in
locating sea ice has come from the radar satellite images from current
SAR
missions such as Envisat. Such 'radar maps' are now available
operationally
through the internet and provide a synoptic view of ice conditions
around Svalbard.
During campaign activities they are an integral
part of the planning meeting held each morning with all the campaign
participants.
The campaign will last about three weeks, but one week in and the first
successful airborne acquisitions have already been made and processed
on site.
Irene Hajnsek from the German Space Agency DLR said that, "What
impresses
me most is the variety and clarity of the different sea ice structures
visible
in the radar images. The dual-polarization C-band images we collected a
few
days ago and closely mimic those of the future Sentinel-1 mission show
an
amazing variety of different ice floes. The different shapes and sizes
are
clearly distinguished in the images because of their texture, and using
both polarizations
at the same time through the roughness shows up as color. It is quite a
challenge to collect and process data over flight legs of 150
kilometers or
more, but looking at these images I know we are on the right track."
The
IceSAR
participants include teams from the Alfred Wegner Institute, the
Microwave and
Radar Institute from the German Space Agency DLR and ESA, and despite
the
numbingly cold conditions the campaign will continue with a number of
other
airborne flights over sea ice in the coming days.
##
Contact:
Malcolm
Davidson
European Space Agency
31-715-655-957
malcolm.davidson@esa.int
This
text derived from:
http://www.esa.int/esaLP/SEMFI0R08ZE_LPcampaigns_0.html
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