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Uncertainty Analysis of Thunderstorm Nowcasts
for Utilization in Aircraft Routing
1
Manuela Sauer1, Thomas Hauf1, Caroline Forster2
1Leibniz Universität Hannover, Institute of Meteorology and Climatology 2DLR, Institute of Physics of the Atmosphere
25. November 2014 – 4th SESAR Innovation Days
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 2
Outline
• Thunderstorms, motivation and nowcast data used
• Methodology and results of the uncertainty analysis
• Application in weather avoidance routing
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 3
Thunderstorms
• Small scale phenomena
– cell diameter: 5 - 50 km
– life time: 20 - 60 min
• After generation: further life cycle and movement
is in principal predictable
• Prediction of onset?
– generation mechanisms need to be forecasted:
• deterministic components: orography, surface convergence lines
• stochastic components: gravity waves, temperature inhomogeneities
not predictable!
UNCERTAINTY
Source: http://www.bom.gov.au/storm_spotters/handbook/thunderstorms.shtml
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 4
Motivation
event
approaching an event in
time and space
lead time
probability
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 5
Rad-TRAM nowcast system Radar Tracking and Monitoring
• Based on radar composit
with timely resolution of
5 minutes
• object-based (> 37 dBZ)
• Pyramidal image matcher
displacement
life cycle: growth and decay
of cells
Source: http://www.pa.op.dlr.de/MUCSOMMER/2012/
Further information:
Tafferner, A., C. Forster, 2012: Weather Nowcasting and Short
Term Forecasting, in Atmospheric Physics,
U. Schumann (ed.), Springer Verlag
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 6
Rad-TRAM nowcasts
time
lea
d tim
e
t0 t5 t10 t15
t
t+5
t+10
t+15
t+20
t+60
t+55
t55 t65
no further
detection of
this cell
…
timely resolution: 5 minutes
horizontal resolution: 2 km
t60
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 7
METHODOLOGY & RESULTS
Nowcast uncertainty determination
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 8
Methodology
Δdistright
Δdistleft
Δdistforward
Δdistback
N
- 0 +
t30,right
Δdistright
N
- 0 +
t30,forward
Δdistforward
N
- 0 +
t30,left
N
- 0 +
t30,backward
Δdistback
Δ = obs - nowcast
Frequency distributions
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 9
Results
Δdistright
Δdistforward
N
t30,forward
Δdistforward
N
t30,back
Δdistback
N
t30,right
Δdistright
Δdistleft
t30,left
N
90th percentile
Cumulative
distribution function
20120715
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 10
Increase of uncertainty with lead time
LEFT RIGHT
lead time
60 min
5 min
35 min
20120715
observation is
always larger
than nowcast in
direction right
17.14 km P90,abs,60min 18.24 km
1.98 km P90,abs,60min 3.79 km
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 11
17.14 km 18.24 km
1.98 km 3.79 km
Increase of uncertainty with lead time
LEFT RIGHT
lead time
60 min
5 min
35 min
20120715
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 12
80% intervals in all directions
100 km
nowcast time: 35 min
moving
direction
RIGHT, 35 min
BACKWARD, 35 min
LEFT, 35 min
FORWARD, 35 min
nowcast
mean uncertainty
10th and 90th
percentile
20120715
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 13
80 % intervals in all directions
moving direction 5 min
60 min
35 min
20120715
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 14
Differing results for different days/situations
July 15th, 2012 July 15th & 10th, 2012
No characteristic distribution
on right extent!
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 15
Separate uncertainty analysis
– propagation error
gravity center
moving direction
5 min
60 min
35 min
distance lateral to mov direction 50 km
Gravity center displacement (rel. to obs)
dis
tance i
n m
ov
direction
50 km
50 km
50 km
50 km
50 km
50 km
50 km
0 km
No systematic
misplacement!
20120715
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 16
Δdistleft
Separate uncertainty analysis
– extension error
gravity center
Δdistright
Δdistforward
Δdistback
5 min
60 min
35 min
distance 30 km
Extension difference in direction RIGHT
rela
tive c
ounts
-30 km
0
1
0
1
0
1
0
30 km -30 km 0
30 km -30 km 0
Relative small
uncertainties
(P90,rel,right,60min = 5.87 km)
20120715
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 17
Correlated distances in separate analysis
Regular growth or
shrinkage on both sides
Equivalent correlation
between FORWARD and
BACKWARD deviations
20120715
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 18
Regressions:
Integrated uncertainty development
20120715
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 19
Integrated uncertainty development
Larger 90th
percentiles
for directions
BACKWARD
and
RIGHT
20120715
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 20
APPLICATION IN
WEATHER AVOIDANCE ROUTING
Nowcast uncertainty determination
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 21
Add uncertainty margin around a nowcast
movement direction
35 minutes
nowcast
of a point cell
90th
percentile
uncertainty
margin
20120715
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 22
movement direction ~ 1.3°
525 km at 480kt
12 km
20120715 Add uncertainty margin around a nowcast
Additional
heading change
to that forced by
the nowcasted
cells extent.
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 23
• Spatial uncertainty determination method of nowcast cells
considering extent and displacement
– Isotropic behavior for both components
– BUT: integrated uncertainty shows characteristic features
Conclusion I
Thank you for your attention!
Integral view Separate view
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 24
• Spatial uncertainty determination method of nowcast cells considering extent and displacement
– Isotropic behavior for both components
– BUT: integrated uncertainty shows characteristic features
• Quantified rate of increasing uncertainty with lead time
.
Conclusion II
Thank you for your attention!
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 25
• Spatial uncertainty determination method of nowcast cells considering extent and displacement
– Isotropic behavior for both components
– BUT: integrated uncertainty shows characteristic features
• Quantified rate of increasing uncertainty with lead time
• Uncertainty is even higher due to
– new, not yet nowcasted cells
– Other not yet considered statistics
• dissipating cells
• merged/splitted cells
• Further analyses on different thunderstorm situations
Conclusion
Uncertainty Analysis of Thunderstorm Nowcasts for Utilization in Aircraft Routing
Manuela Sauer et al. 4th SESAR Innovation Days, Madrid 26
THANK YOU
Contact information:
Manuela Sauer [email protected]
Thomas Hauf [email protected]
Caroline Forster [email protected]