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Space-time
interpolation
of nocturnal bird migration
Raphaël Nussbaumer1,2, Lionel Benoit1,
Grégoire Mariethoz1, Felix Liechti2, Baptiste Schmid2
1 2
Objective
High resolution interpolation of nocturnal bird migration
at continental scale from weather radars
time
Motivation
Reveal spatio-temporal pattern of migration
Data Exploration
What can we observe in the data? Method
How to build this model? Result
What can we do with this?
Plan
ResultMethodData exploration
t
P
ZN=
radar cross section (RCS)
Reflectivity factor
Number of targets
ResultMethodData exploration
Adapted from Dokter (2011)
ResultMethodData exploration
19 sept. –10 oct. 2016
69 radars
enram/data-repository
5-15min
ResultMethodData exploration
[Log bird/km3]
[bird/km2]
Vol2bird1
+
manual
cleaning
Vertical
Integration
1 Dokter, et al. (2011)
ResultMethodData exploration
Objective
time
time
ResultMethodData exploration KrigingCovariance function
ResultMethodData exploration
( )
,Zts
p
( )
ts
TREND AMPLITUDE CURVE RESIDUBIRD DENSITY
=
+
+
+
Transformed bird density Zp
ResultMethodData exploration
R
c
A
t
( )
,Zts
p
( )
,Ats
( )
ts
( )
ct
( )
,Rts
TREND AMPLITUDE CURVE RESIDUBIRD DENSITY
=
+
+
+
ResultMethodData exploration
Inference
ResultMethodData exploration
Inference
ResultMethodData exploration
Inference
ResultMethodData exploration
Cross-Validation
ResultMethodData exploration
Validation
Herzeele (FR)
Sempach (CH)
ResultMethodData exploration
ResultMethodData exploration
Total number of birds [over the study area]
(100 of millions)
How many birds are migrating?
ResultMethodData exploration
( )
1 0
,Bt
−
s
( )
1 0
,Bt
+
s
( )
00
,Bts
Space
( )
0 1
,Bt
+
s
Time
Departed/Arrival
Where [and when] do they stop?
() y
xBv
Bv
BB
t x y
= − = − +
v
Continuity Equation
•Real-time availability
•Interpolation of flight -> flux
•Departure and arrival
Conclusion Outlooks
•Spatio-temporal interpolation
•Bird density anywhere
•Total number of bird over an
area
www.bmm.raphaelnussbaumer.com Rafnuss-PostDoc/BMM
project/Bird-Migration-Modelling-BMM
Thank you for your attention