Bird migration monitoring across Europe using

Transcription

1 Bird migration monitoring across Europe using weather radar M. de Graaf, H. Leijnse, A. Dokter, J. Shamoun-Baranes, H. van Gasteren, J. Koistinen, and W. Bouten 7th European Conference on Radar in Meteorology and Hydrology

2 Bird migration monitoring across Europe using weather radar Introduction OPERA Network participants Bird retrieval algorithm Clutter Conclusion 2

3 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) 3

4 OPERA network Flysafe2: Expand the network by including more operational European weather radars to monitor and predict migratory bird movements over a large area 4

5 ENRAM network European Network for the Radar Surveillance of Animal Migration (ENRAM) Radar data from 15 Aug 15 Sep 2011 was supplied by: Czech Republic Finland Ireland France United Kingdom Norway Netherlands Poland Portugal Slovakia Slovenia Switzerland Sweden 5

6 ENRAM network European Network for the Radar Surveillance of Animal Movement (ENRAM) Radar data from 15 Aug 15 Sep 2011 was supplied by: Czech Republic Finland Ireland France United Kingdom Norway Netherlands Poland Portugal Slovakia Slovenia Switzerland Sweden Germany: test set provided Italy: Restrictive data policy 6

7 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

8 Bird retrieval algorithm Precipitation 27 Sep. 2007, 22:23 UTC Reflectivity factor Z Radial velocity v r Velocity variation σ v 8

9 Bird retrieval algorithm Clear air (insects) 23 Sep. 2007, 22:23 UTC Reflectivity factor Z Radial velocity v r Velocity variation σ v 9

10 Bird retrieval algorithm Birds 5 Oct. 2007, 22:23 UTC Reflectivity factor Z Radial velocity v r Velocity variation σ v 10

11 Velocity variation Birds Convective precipitation Wideumont 11

12 Velocity variation Wideumont Smaller range resolution De Bilt Larger range resolution Stronger clutter 12

13 2012 De Bilt 1-6 June

14 Clutter Clutter filtering is very important for retrieval of small bird echoes Depends strongly on location Depends on weather conditions Depends on the ground conditions 14

15 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 15

16 Clutter filter PDF over 2011 PDF over April th percentile (2011) median (2011) mode (2011) Use statistics of e.g. yearly or monthly data probability density dbz

17 De Bilt radar 05 % clutter definition 17

18 De Bilt radar 25 % clutter definition 18

19 De Bilt radar 50 % clutter definition 19

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23 Conclusions Aerial bird densities from Doppler radar can be retrieved operationally ENRAM network will work toward European-wide aerial bird density estimates Dynamic and automated clutter removal is important 23

24 Den Helder radar 24

25 Bird migration on weather radar Example 17 October 2008 Redwing Turdus iliacus Kilometers

26 Kilometers Bird migration on weather radar Example 17 October reflectivity factor radial velocity 50 km 26

27 Kilometers Bird migration on weather radar Example 17 October reflectivity factor radial velocity 50 km 27

28 Thank you 28

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