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METLIFT - A NEW DEVICE FOR ACCURATE MEASUREMENTS OF METEOROLOGICAL PARAMETERS IN A
SNOW RICH ENVIRONMENT Manfred Dorninger
University of Vienna, Department of Meteorology and Geophysics; Vienna, Austria; email: [email protected]
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Tem
pera
ture
(d
eg
ree C
)
snow-free
snow-covered
Problems for accurate measurements in mountainous
terrain • deep snow pack
• remote locations
• no external power supply
• very low temperatures
Consequences • sensor height above surface is unknown for increasing and decreasing snow
pack and does not follow WMO recommendations
• surface stations may be snow covered
• station may stop logging due to power failure because of low temperatures
(below -40 degree C).
Current solution • several sensors are mounted on a mast at different heights
• logger mounted at the ground under the snow pack to protect it against too low
temperatures
Disadvantages • exact position of the sensor above snow surface is never known
• dig out the logger for downloading station data (only during fine weather
episodes possible in winter time)
• no real-time data delivery
Figure 1: Illustration of measurements problems in snow rich and remote
mountainous regions. a) Temperature sensor almost snow covered; b) Wind
anemometer of weather station only about 50cm above snow surface; c) students
are digging out the station; d) data download from the snow covered loggers.
Trafelberg: 3.- 4. January 2011
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time (LT)
Te
mp
era
ture
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ree
C)
a) b) c) d)
Figure 2: Two temperature records at
Grünloch, Lower Austria for a winter
time period in 2006: blue: sensor
above snow surface; red: sensor
snow-covered.
Figure 3: Three temperature records
for a clearing winter night: green:
20cm; blue: 120cm and pink: 220cm
above snow surface.
Radio antenna
From the idea …
… to reality
Figure 3: Construction plans of METLIFT. Automatic adaptation of lift
position via snow height sensor measurements. Left: lifting mechanism,
realised via a winch and a hoist. Right: Detailed front view of METLIFT.
Figure 4: Prototype of
METLIFT at Trafelberg,
Lower Austria.
Data transmission check
data flow from the logger via radio signal and GSM signal to a server and real-
time availability has been tested.
Energy consumption check
extensive checks have been performed to optimize the energy consumption of
the whole system.
Icing check
icing conditions have been simulated by sprinkling the tower during very cold
winter days. The lifting device can deal very well with such harsh conditions.
The solution
In close cooperation with the technical high school in Waidhofen/Ybbs, Lower
Austria, a new device was developed to guarantee the sensor height above
Surface within the WMO limits in harsh and remote environments. An ultrasonic
snow height sensor measures the distance to the snow surface. If it exceeds
certain limits due to snow accumulation or snow melt the lift adapts its height
accordingly.
Radiation balance
Wind vane
Snow height sensor
T/RH sensor
Box with electromotor and
accus (waterproof).
GSM antenna
Extensive system checks have been performed before METLIFT has been
brought into the field.
Some technical details
Power supply • three lead gel accumulators (12V, 85Ah, Fig. 5)
• recharged by three solar panels (105Wp each)
• accus and electromotor will be snow-covered
Lifting mechanism • lifting control box developed
by HTL Waidhofen/Ybbs
•12V Electromotor (Fig. 5)
• transmission rate 2856:1
• winch and hoist
Figure 5: Accus, lifting control box,
electromotor and winch. All components are
fixed at the ground.
Data logging and transmission • all electronic units (Fig. 6) are checked for
temperatures down to -50 degree C
• lightning protection provided
• radio transmission to nearby mountain
station or GSM transmission
• manual switchers provided to operate the
lift in the case of an electronic failure
Figure 6: Electronic control
box with data logger and
radio transmission unit, will
be lifted.
Acknowledgements: The cooperation with the
technical high school HTL Waidhofen/Ybbs is
highly appreciated. My special thanks go to K.
Eglseer, W. Langsenlehner, J. Leichtfried and to
the students M. Höller, M. Freynhofer, R.
Höflehner, N. Lehner and B. Pribil.
Figure 7: METLIFT at its
maximum lifting height of 4m.
