bird migration monitoring across europe using …...radar data from 15aug –15sep 2011 was supplied...
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Bird migration monitoring across Europe using weather radarweather radar
M. de Graaf, H. Leijnse, A. Dokter, J. Shamoun-Baranes, H. van Gasteren, J. Koistinen, and W. Bouten
ERAD 2012 | 24-29 June Toulouse
7th European Conference on Radar in Meteorology and Hydrology
Bird migration monitoring across Europe using weather radar
Introduction
OPERA Network participants
Bird retrieval algorithmBird retrieval algorithm
Clutter
Conclusion
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Introduction
Flysafe 2:
• Build on Flysafe: Bird strike avoidance for civil and military aviation
• Financed by the Dutch Royal Airforce
• Extend bird retrieval algorithm to European partner radar stations
• Collaboration with ecological and meteorological institutes from Finland, the UK, Germany, Sweden, Denmark and Switzerland within ENRAM (European Network for the Surveillance of Animal Movement)
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OPERA networkFlysafe2:
Expand the network by including more operational European weather radars to monitor and predict migratory bird movements over a large area
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ENRAM network European Network for the Radar Surveillance of Animal Migration (ENRAM)Radar data from 15 Aug – 15 Sep 2011 was supplied by:
Czech RepublicFinlandIrelandFrance
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FranceUnited KingdomNorwayNetherlandsPolandPortugalSlovakiaSloveniaSwitzerlandSweden
ENRAM network European Network for the Radar Surveillance of Animal Movement (ENRAM)Radar data from 15 Aug – 15 Sep 2011 was supplied by:
Czech RepublicFinlandIrelandFrance
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FranceUnited KingdomNorwayNetherlandsPolandPortugalSlovakiaSloveniaSwitzerlandSweden
Germany: test set providedItaly: Restrictive data policy
Bird retrieval algorithm
C-band Doppler weather radar (5-25 km distance, 0-6 km altitude)
- Filter clutter (velocity < ± 1 ms-1 and static clutter map)- Filter precipitation (0 dBZ threshold and uniform filling)- Find high velocity variations
Precipitation Insects Birds
Reflectivity ++ -- --
Refl. uniformity ++ - --
Velocity + + +
Vel. homogeneity
++ + --
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Bird retrieval algorithm
Precipitation 27 Sep. 2007, 22:23 UTC
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Reflectivity factor Z Radial velocity vr Velocity variation σv
Bird retrieval algorithm
Clear air (insects) 23 Sep. 2007, 22:23 UTC
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Reflectivity factor Z Radial velocity vr Velocity variation σv
Bird retrieval algorithm
Birds 5 Oct. 2007, 22:23 UTC
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Reflectivity factor Z Radial velocity vr Velocity variation σv
Velocity variation
Birds
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Wideumont
Convective precipitation
Velocity variation
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Wideumont De Bilt
Smaller range resolutionLarger range resolutionStronger clutter
De Bilt
2012
13
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De Bilt1-6 June 2012
2012
Clutter
Clutter filtering is very important for retrieval of small bird echoes
• Depends strongly on location
• Depends on weather conditions
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• Depends on weather conditions
• Depends on the ground conditions
Clutter filter 1
• Find a few days in winter w/o birds and precipitation, and average. Define all pixels with reflectivity above threshold as clutter
threshold = -10 dBZ
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threshold = -10 dBZ
Clutter filter 2
• Use statistics of e.g. yearly or monthly data
0.10
0.12
0.14
y
PDF over 2011PDF over April 201225th percentile (2011)median (2011)mode (2011)
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−20 0 20 40
0.00
0.02
0.04
0.06
0.08
dBZ
prob
abili
ty d
ensi
ty
05 %De Bilt radar clutter definition
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25 %De Bilt radar clutter definition
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50 %De Bilt radar clutter definition
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20
21
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Conclusions
• Aerial bird densities from Doppler radar can be retrieved operationally
• ENRAM network will work toward European-wide aerial
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• ENRAM network will work toward European-wide aerial bird density estimates
• Dynamic and automated clutter removal is important
Den Helder radar
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RedwingTurdus iliacus
Bird migration on weather radarExample 17 October 2008
25
355˚ 0˚ 5˚ 10˚10˚
50˚
55˚
0 100 200
Kilometers
Turdus iliacus
355˚ 0˚ 5˚ 10˚10˚
50˚
55˚
0 100 200
Kilometers
reflectivity factor radial velocity
Bird migration on weather radarExample 17 October 2008
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50 km
355˚ 0˚ 5˚ 10˚10˚
50˚
55˚
0 100 200
Kilometers
reflectivity factor radial velocity
Bird migration on weather radarExample 17 October 2008
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50 km
Thank youThank you
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