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Assessment of potential radar locations using
a beam propagation model
Günther Haase, SMHI
Uta Gjertsen, met.no
Joan Bech, meteocat
2020-04-24
ERAD 2006, Barcelona
Åsa Granström, SMHI
ERAD 2006, Barcelona
18 - 22 September 2006
2020-04-24
ERAD 2006, Barcelona
Radar Hemse (Gotland)
… has to be moved by
June 2007 because the
agricultural silo will be
demolished.
Possible locations
Check
 property rights
Gotland
 technical infrastructure (roads,
electricity, telecommunication, …)
 vegetation
 nearby obstacles (church & GSM
towers, wind mills, …)
 topographical blockages
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ERAD 2006, Barcelona
 electromagnetic interferences
(e.g. RLAN)
 distance to the Baltic Sea
Which locations should be avoided?
 experiences from previous radar
removals (3)
Narrow blockages
Beam blockage factor (C): 0 ≤ C ≤ 1
C
338 m
3m
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ERAD 2006, Barcelona
Visby tower
wind mill
cross section of the tower hit by the radar beam
cross section of the radar beam at the tower
Accumulations for existing sites:
Topographical blockages:
Beam Propagation Model (BPM)
Input
 DEM (1 km resolution in polar-stereographic projection)
 vertical profiles of temperature and humidity from radiosondes or NWP
model at the radar site
 radar characteristics (e.g. position, elevation angles, spread angle, …)
Output
 degree of shielding
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ERAD 2006, Barcelona
 height of lower beam edge
 correction factor for topographic blockages
 quality index fields in polar coordinates for
all Nordrad radars (ongoing)
BPM: atmospheric standard conditions
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ERAD 2006, Barcelona
beam blockage
beam height
 standard refraction (dN/dz = -39 N-units/km)
 no beam blockage for Hemse and the other 10 options
BPM: AP conditions
9 July 2005 00 UTC
HEM
beam blockage (Hirlam)
beam height (Hirlam)
observation
RS
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G09
ERAD 2006, Barcelona
 BPM input: 6-hour
Hirlam fcst (11 km)
RS
 beam blockage
simulated and
observed for HEM
 no beam blockage
simulated for G09
Summary
 radar Hemse has to be moved to a new location by June 2007
 practical and theoretical assessment of 10+1 alternatives
 BPM simulations for atmospheric standard conditions and AP situations
(with Hirlam input) are used to discard possible locations
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ERAD 2006, Barcelona
 status: no decision yet on a new radar location