SOUSY

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SOUSY Svalbard Radar for atmospheric
research to study weather, winds, waves and
turbulence in the polar region A contribution
to understand Global Climate Change SOUSY-SMART S
valbard Middle Atmosphere Research and Technology
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The studies of Sun-Earth relations comprise a
multidisciplinary synergy of science and
education. Such studies are performed on a global
scale. The polar regions are of high relevance,
since in the polar upper atmosphere phenomena
from above, resulting from the effect of the
solar wind on the Earth's atmosphere and
ionosphere and phenomena from below, such as
atmospheric waves propagating upwards from the
lower atmosphere, are merging. The relative
importance of these effects from above and below
are studied continuously and extensively. The
polar summer mesosphere is extremely cold between
80 km and 90 km altitude, such that ice particles
form, resulting in Noctilucent Clouds and in
particular radar scattering, manifest in Polar
Mesosphere Summer Echoes known as PMSE. The polar
stratosphere (10-50 km) and troposphere (0-10 km)
are strongly affected by dynamic processes
occurring in connection with the polar vortex.The
relation to weather changes and the ozone budget
in polar regions is evident. Mesosphere-stratosph
ere-troposphere (MST) radars have proved to
contribute significantly to the studies of these
processes. For this purpose the
Max-Planck-Institut für Aeronomie had set up an
MST VHF radar in Longyearbyen on Svalbard the
SOUSY Svalbard Radar (78N, 16E). It is obvious
that such MST radar studies are carried out in
combination with other related observations, i.e.
with the EISCAT Svalbard Radar, and with several
in-situ and ground-based experiments performed by
several research groups to study the polar
atmosphere, enhanced by introducing new
technology (SOUSY-SMART).
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The SOUSY Svalbard Radar (SOUSY) operates on
53.5 MHz with an average power up to 3 kW, a
high-gain 356 Yagi-antenna array of 95 meters
diameter (see left-side photo), allowing five
beam pointing directions at and close to the
zenith. In addition the system consists of
digital radar control, a high sensitivity
receiver and signal processing units. Raw data
are stored on disk, tape and CD-ROM. Result data
can also be displayed in real-time on-site and
and on the internet, presently under Radars am
IAP, Svalbard, Aktuelle Messung, PMSE,
Troposphäre at ltwww.iap-kborn.de/messungen/index_
d.htmgt
Impressive echoes can frequently be ob- served
from altitudes 80-110 km, which result of scatter
from meteors.The above panel shows a meteor echo
lasting over almost 10 seconds.These echoes
provide information on the orbit of the
originating meteorite and the meteor shower.
Atmospheric winds and temperatures are deduced
from the meteor echo trail. During summer
months strong echoes occur from altitudes 80 km
to 95 km, which are the co-called Polar
Mesosphere Summer Echoes (PMSE). The lower panel
shows a 12-hour sequence of the echo power, the
vertical air velocity and turbulence intensity
observed with the SSR over Longyearbyen on 13
June 1999. These PMSE are sensible tracers of
atmospheric waves. A se-quence of these, covering
a period of one hour, is shown in the upper
right-hand panel.The vertical velocity amplitudes
can be as large as 5 m/s. The long-term
observations of these PMSE over Svalbard can be
used as an indicator of global change of
temperature and water vapor at these altitudes.
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The SOUSY-SMART Radar is a proper instrument for
studies of these PMSE. The combination with the
EISCAT Svalbard Radar provides a unique and novel
tool for investigating the complex scatter
processes from the dusty plasma in the very high
latitude summer mesopause region. The suitable
combination with other instruments, such as
optical observations by spectrometers and lidars
etc., together with educational facilities, such
as UNIS, makes Longyearbyen a globally
outstanding focal point for middle and upper
atmosphere science. In addition, the SSR is an
appropriate instrument for investigations of the
meteorology of the lower stratosphere and
troposphere. It is the first radar of this kind
at the high polar latitudes of 78 degrees North.
The SOUSY Svalbard Radar SMART can continuously
measure the horizontal and vertical wind in the
lower atmosphere up to about 15 km height with a
resolution of 150 meters. The radar reflectivity,
related to the radar echo power, provides most
valuable information on the height and structure
of the tropopause and weather fronts. Examples of
such data, collected over a period of four days,
are presented in the figure, where the upper
panel shows the vertical velocity and the lower
panel the radar reflectivity. The variation of
the tropopause (green band in the middle of the
lower panel) are indicators of regions of
troposphere-stratosphere exchange, which have an
effect on the ozone budget in the Arctic. Such
profiles can be obtained with a best time
resolution of 30 seconds. They are highly useful
for detection of clear-air turbulence (large
vertical velocity variations up to 1-2 m/s
(red/green) observed in the beginning and the
middle of the shown period), which would be
useful for air traffic warning, and can be
applied for improved weather forecasting (winds
and rain/snow in Longyearbyen) by real-time
analyzing variations of frontal structures aloft
by operating the SOUSY Svalbard Radar in the wind
profiler mode. SOUSY stands for SOUnding SYstem
- a system of instruments to remotely sound the
atmosphere from the ground. The SOUSY Svalbard
Radar has now been taken ove by the University in
Tromsø and should be upgraded with new
technology SOUSY Svalbard Middle Atosphere
Research and Technology (SMART). This will widen
the scientific community and increase the
research results, which are highly useful for
better understanding of the Earths atmosphere
and space environment, and for studies of global
climate change. _at_ jr, Max-Planck-Institut für
Aeronomie, 37191 Katlenburg-Lindau, Germany,
February 2002. The SOUSY Svalbard Radar SMART is
now operated by the Tromsø Geophysical
Observatory, University of Tromsø, Norway,
October 2003.