Convection-permitting ensemble simulations and ...€¦ · Convection-permitting ensemble...
40
Convection-permitting ensemble simulations and Mediterranean HPEs Benoît Vié 1 Olivier Nuissier 1 Véronique Ducrocq 1 1 Météo-France - CNRM 1 August 2011
Transcript of Convection-permitting ensemble simulations and ...€¦ · Convection-permitting ensemble...
Convection-permittingensemble simulationsandMediterranean HPEs
Benoît Vié1
Olivier Nuissier1
Véronique Ducrocq1
1Météo-France - CNRM
1 August 2011
Why do we need a convection-permitting EPS?
Z500
925 hPa wind925 hPa θ
′
w
10
15
20
25
30
40
55
75
100
150
250
300
400
24h accumulated precipitation, 12 UTC 2 Nov.2008, AROME forecast and observations
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D1
Why do we need a convection-permitting EPS?
◮ Convection-permitting,non-hydrostatic NWP models producevery realistic forecasts
◮ Realistic 6= Real
◮ Runoff forecasts are very sensitive tothe rainfall forecasts, especially forsmall and steep mountainouswatersheds
◮ EPSs are one method to evaluate theforecast uncertainty
10
15
20
25
30
40
55
75
100
150
250
300
400
24h accumulated precipitation, 12 UTC 2 Nov.2008, AROME forecast and observations
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D1
The AROME model (late 2008)
◮ Non-hydrostatic
◮ 2.5 km horizontal grid spacing
◮ 41 vertical levels
◮ 3D-VAR data assimilation scheme
◮ Bulk microphysics parameterization,6 prognostic water variables: watervapour, cloud water, rainwater,primary ice, graupel and snow(Pinty and Jabouille, 1998, Caniaux,1994)
FRANCE
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D2
AROME forecasts and uncertainty12 UTC06 UTC00 UTC 18 UTC 00 UTC 06 UTC 12 UTC
ALADIN
AROME
(10 km)
(2.5 km)
ALADIN & AROME data assimilation cycle
24-h forecasts
LBCs ICs
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D3
AROME forecasts and uncertainty12 UTC06 UTC00 UTC 18 UTC 00 UTC 06 UTC 12 UTC
ALADIN
AROME
(10 km)
(2.5 km)
ALADIN & AROME data assimilation cycle
24-h forecasts
LBCs ICs
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D3
AROME forecasts and uncertainty12 UTC06 UTC00 UTC 18 UTC 00 UTC 06 UTC 12 UTC
ALADIN
AROME
(10 km)
(2.5 km)
ALADIN & AROME data assimilation cycle
24-h forecasts
LBCs ICs
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D3
The Ensemble experiments
AROME-PEARP◮ Each AROME assimilation cycle uses LBCs from one
PEARP (global, short range ensemble) member
AROME-PERTOBS◮ Unique LBCs from the deterministic large scale forecast◮ Each AROME assimilation cycle uses randomly perturbed
observations
◮ The AROME-PEARP ensemble samples the uncertaintyon synoptic-scale LBCs and initial conditions
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D4
The Ensemble experiments
AROME-PEARP◮ Each AROME assimilation cycle uses LBCs from one
PEARP (global, short range ensemble) member
AROME-PERTOBS◮ Unique LBCs from the deterministic large scale forecast◮ Each AROME assimilation cycle uses randomly perturbed
observations
◮ The ensemble data assimilation technique is known tosample the analysis error quite well (Berre et al., 2006)
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D4
The Ensemble experiments
AROME-PEARP◮ Each AROME assimilation cycle uses LBCs from one
PEARP (global, short range ensemble) member
AROME-PERTOBS◮ Unique LBCs from the deterministic large scale forecast◮ Each AROME assimilation cycle uses randomly perturbed
observations
AROME-COMB◮ LBCs from one PEARP member◮ Assimilation of randomly perturbed observations
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D4
Evaluation period
31 (18) days◮ 6 October 2008 -> 5 November 2008 (31 days)◮ 15 October 2008 -> 1 November 2008 (18 days)
◮ 20 October 2008observed daily precipitation
◮ 1-2 November 2008observed daily precipitation
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D5
Results
Vié, B., O. Nuissier and V. Ducrocq, 2011: Cloud-resolving ensemble simulations ofMediterranean Heavy Precipitating Events: Uncertainty on initial conditions and lateralboundary conditions, MWR, 139:403-423
◮ The impact of uncertainty on LBCs rapidly overcomes the impact of uncertaintyon ICs (after around 12 h in our configuration)
◮ The relative impact of ICs and LBCs depends on the meteorological situation
◮ The spread in the AROME-PEARP ensemble represents a temporal or spatialuncertainty better (it has a wider geographical extent)
◮ Promising precipitation scores, despite the underdispersion for low-levelparameters
◮ The combination of both sources of uncertainty in the AROME-COMB ensembleimproves the performance
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D6
Selective perturbation of observations
◮ Focus on important low-level parameters for the HPEs, as identified throughcase studies (O. Nuissier, V. Ducrocq) and idealized simulations (E. Bresson)
wind speed
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
humidity
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
temperature
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
00 UTC 31 Oct. 2010, 12-h accumulated precipitation, AROME forecasts
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D7
Taking model errors into consideration
With collaboration from É. Richard, S. Fresnay and A. Hally, Laboratoire d’Aérologie,Toulouse, France.
◮ Perturbation of 3 microphysical tendencies:
◮ autoconversion◮ accretion◮ evaporation
◮ No effect on probabilistic scores
◮ For some special cases, changes both the intensity and position of theprecipitating system
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D8
Taking model errors into consideration
20 Oct. 2008, 00 UTC + 12 h, θv (colours), CWC (black), RWC (gray)
4.0E43ON 43.2ON 43.4ON 43.6ON 43.8ON 44ON 44.2ON 44.4ON 44.6ON 44.8ON 45ON
1000
950
900
850
800
750
700
650
600
0.00
04
0.0004
0.0004
0.00
04
0.00
04
0.00
08
0.0008
0.0008
0.00
04
0.00
04
0.0004
0.00
04
0.00
04
0.00
040.0008
289.3
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
4.0E43ON 43.2ON 43.4ON 43.6ON 43.8ON 44ON 44.2ON 44.4ON 44.6ON 44.8ON 45ON
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D9
Taking model errors into consideration
20 Oct. 2008, 00 UTC + 15 h, θv (colours), CWC (black), RWC (gray)
4.0E43ON 43.2ON 43.4ON 43.6ON 43.8ON 44ON 44.2ON 44.4ON 44.6ON 44.8ON 45ON
1000
950
900
850
800
750
700
650
600
0.00
04
0.0004
0.00
040.
0004
0.00
08
0.00
120.
0012
0.00
04
0.00
04
0.0004
0.00
04 0.0004
0.00
04
0.0004
0.00
04
0.0004
0.00
04
0.00
080.
0008
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
309.8
4.0E43ON 43.2ON 43.4ON 43.6ON 43.8ON 44ON 44.2ON 44.4ON 44.6ON 44.8ON 45ON
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D9
Taking model errors into consideration
20 Oct. 2008, 00 UTC + 18 h, θv (colours), CWC (black), RWC (gray)
4.0E43ON 43.2ON 43.4ON 43.6ON 43.8ON 44ON 44.2ON 44.4ON 44.6ON 44.8ON 45ON
1000
950
900
850
800
750
700
650
600
0.00
04
0.00
04
0.00
04
0.00040.0004
0.00
04
0.00
04
0.00
04
0.00
04
0.0004
0.00
08
0.00
08
0.00
04
0.0004
0.00
04
0.0004
0.0004
0.00
08
0.0008
0.00
12
0.00
16
0.002
0.002289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
309.9
4.0E43ON 43.2ON 43.4ON 43.6ON 43.8ON 44ON 44.2ON 44.4ON 44.6ON 44.8ON 45ON
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D9
Ensemble spread
◮ Ensemble combining all the three sources of uncertainty◮ Average over 18 days◮ Vertical profiles of ensemble spread and RMSE for temperature
300
400
500
600
700
800
900
1000 0 0.5 1 1.5 2
alt
000306121824
◮ Ensemble spread
300
400
500
600
700
800
900
1000 0 0.5 1 1.5 2
alt
000306121824
◮ RMSE
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D10
Conclusions & prospects
Vié, B., O. Nuissier and V. Ducrocq, 2011: Cloud-resolving ensemble simulations ofMediterranean Heavy Precipitating Events: Uncertainty on initial conditions and lateralboundary conditions, MWR, 139:403-423
◮ Uncertainty on LBCs has the strongest impact on the CPM forecasts
◮ Focus on the predictability of HPEs or design a generic EPS?
◮ Better sampling of model errors (e.g. stochastic physics, F. Bouttier)
◮ Introducing perturbations of the low-level conditions (surface fields, orography...)
◮ Select a few representative members from a global ensemble (O. Nuissier)
◮ Perform a hydrometeorological evaluation of the ensemble forecasts within theframework of the MEDUP project, article to be submitted in NHESS (incollaboration with G. Molinié, LTHE, and B. Vincendon)
◮ Sept-Oct 2013: Special Observing Period of HyMeX
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D11
Conclusions & prospects
Vié, B., O. Nuissier and V. Ducrocq, 2011: Cloud-resolving ensemble simulations ofMediterranean Heavy Precipitating Events: Uncertainty on initial conditions and lateralboundary conditions, MWR, 139:403-423
◮ Uncertainty on LBCs has the strongest impact on the CPM forecasts
◮ Focus on the predictability of HPEs or design a generic EPS?
◮ Better sampling of model errors (e.g. stochastic physics, F. Bouttier)
◮ Introducing perturbations of the low-level conditions (surface fields, orography...)
◮ Select a few representative members from a global ensemble (O. Nuissier)
◮ Perform a hydrometeorological evaluation of the ensemble forecasts within theframework of the MEDUP project, article to be submitted in NHESS (incollaboration with G. Molinié, LTHE, and B. Vincendon)
◮ Sept-Oct 2013: Special Observing Period of HyMeX
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D11
Conclusions & prospects
Vié, B., O. Nuissier and V. Ducrocq, 2011: Cloud-resolving ensemble simulations ofMediterranean Heavy Precipitating Events: Uncertainty on initial conditions and lateralboundary conditions, MWR, 139:403-423
◮ Uncertainty on LBCs has the strongest impact on the CPM forecasts
◮ Focus on the predictability of HPEs or design a generic EPS?
◮ Better sampling of model errors (e.g. stochastic physics, F. Bouttier)
◮ Introducing perturbations of the low-level conditions (surface fields, orography...)
◮ Select a few representative members from a global ensemble (O. Nuissier)
◮ Perform a hydrometeorological evaluation of the ensemble forecasts within theframework of the MEDUP project, article to be submitted in NHESS (incollaboration with G. Molinié, LTHE, and B. Vincendon)
◮ Sept-Oct 2013: Special Observing Period of HyMeX
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D11
Conclusions & prospects
Vié, B., O. Nuissier and V. Ducrocq, 2011: Cloud-resolving ensemble simulations ofMediterranean Heavy Precipitating Events: Uncertainty on initial conditions and lateralboundary conditions, MWR, 139:403-423
◮ Uncertainty on LBCs has the strongest impact on the CPM forecasts
◮ Focus on the predictability of HPEs or design a generic EPS?
◮ Better sampling of model errors (e.g. stochastic physics, F. Bouttier)
◮ Introducing perturbations of the low-level conditions (surface fields, orography...)
◮ Select a few representative members from a global ensemble (O. Nuissier)
◮ Perform a hydrometeorological evaluation of the ensemble forecasts within theframework of the MEDUP project, article to be submitted in NHESS (incollaboration with G. Molinié, LTHE, and B. Vincendon)
◮ Sept-Oct 2013: Special Observing Period of HyMeX
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D11
Questions ?
The AROME-PEARP experiment
(x11) (x11) (x11)
12 UTC06 UTC00 UTC 18 UTC 00 UTC 06 UTC 12 UTC
PEARP
ALADIN
AROME
(23 km)
(10 km)
(2.5 km)
(x11)
(x11)
AROME & ALADIN Data Assimilation Cycle
24-h forecasts
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D13
The AROME-PERTOBS experiment
12 UTC06 UTC00 UTC 18 UTC 00 UTC 06 UTC 12 UTC
ALADIN
AROME
(10 km)
(2.5 km)
AROME(2.5 km)
&
(x10)
ALADIN & AROME data assimilation cycle
24-h forecasts
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D14
Example on a case study: 1-2 Nov. 2008
AROME-PEARP AROME-PERTOBS AROME-COMB
h03 h06 h09 h12 h15 h18 h21 h24
12
34
56
7 P0P1P2P3P4P5P6P7P8P9P10Obs.
Forecast range (h)
Pre
cipi
tatio
n m
ean
(mm
)
FREQ
5
10
20
30
40
50
60
70
80
90
100
RR24 ≥ 50 mm probability
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D15
Example on a case study: 1-2 Nov. 2008
AROME-PEARP AROME-PERTOBS AROME-COMB
h03 h06 h09 h12 h15 h18 h21 h24
12
34
56
7 P0P1P2P3P4P5P6P7P8P9P10Obs.
Forecast range (h)
Pre
cipi
tatio
n m
ean
(mm
)
FREQ
5
10
20
30
40
50
60
70
80
90
100
RR24 ≥ 50 mm probability
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D15
Example on a case study: 1-2 Nov. 2008
AROME-PEARP AROME-PERTOBS AROME-COMB
h03 h06 h09 h12 h15 h18 h21 h24
12
34
56
7 P0P1P2P3P4P5P6P7P8P9P10Obs.
Forecast range (h)
Pre
cipi
tatio
n m
ean
(mm
)
FREQ
5
10
20
30
40
50
60
70
80
90
100
RR24 ≥ 50 mm probability
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D15
Example on a case study: 1-2 Nov. 2008
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
AROME-PEARP
24h accumulatedprecipitation,12 UTC 2 Nov. 2008
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D16
Example on a case study: 1-2 Nov. 2008
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
AROME-PERTOBS
24h accumulatedprecipitation,12 UTC 2 Nov. 2008
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D17
Example on a case study: 1-2 Nov. 2008
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
AROME-COMB
24h accumulatedprecipitation,12 UTC 2 Nov. 2008
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D18
Case study: 20 Oct. 2008
AROME-PEARP AROME-PERTOBS AROME-COMB
h03 h06 h09 h12 h15 h18 h21 h24
0.0
0.5
1.0
1.5
2.0 P0
P1P2P3P4P5P6P7P8P9P10Obs.
Forecast range (h)
Pre
cipi
tatio
n m
ean
(mm
)
FREQ
5
10
20
30
40
50
60
70
80
90
100
RR24 ≥ 50 mm probability
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D19
Case study: 20 Oct. 2008
AROME-PEARP AROME-PERTOBS AROME-COMB
h03 h06 h09 h12 h15 h18 h21 h24
0.0
0.5
1.0
1.5
2.0 P0
P1P2P3P4P5P6P7P8P9P10Obs.
Forecast range (h)
Pre
cipi
tatio
n m
ean
(mm
)
FREQ
5
10
20
30
40
50
60
70
80
90
100
RR24 ≥ 50 mm probability
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D19
Case study: 20 Oct. 2008
AROME-PEARP AROME-PERTOBS AROME-COMB
h03 h06 h09 h12 h15 h18 h21 h24
0.0
0.5
1.0
1.5
2.0 P0
P1P2P3P4P5P6P7P8P9P10Obs.
Forecast range (h)
Pre
cipi
tatio
n m
ean
(mm
)
FREQ
5
10
20
30
40
50
60
70
80
90
100
RR24 ≥ 50 mm probability
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D19
Case study: 20 Oct. 2008
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
AROME-PEARP
24h accumulatedprecipitation,12 UTC 2 Nov. 2008
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D20
Case study: 20 Oct. 2008
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
AROME-PERTOBS
24h accumulatedprecipitation,12 UTC 2 Nov. 2008
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D21
Case study: 20 Oct. 2008
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
10
15
20
25
30
40
55
75
100
150
250
300
400
AROME-COMB
24h accumulatedprecipitation,12 UTC 2 Nov. 2008
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D22
Precipitation: ROC and reliability diagram
Relative Operating Characteristics◮ Probability Of Detection against False Alarm Rate◮ The upper the curve is, the better the resolution of the
ensemble is
Reliability diagram◮ Observed frequency
againstforecast probability
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1
PO
D
FAR
AROME-PEARPAROME-PERTOBS
AROME-COMB
RR24 ≥ 0.5 mm
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1
PO
D
FAR
AROME-PEARPAROME-PERTOBS
AROME-COMB
RR24 ≥ 10 mm
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1
Obs
erve
d fr
eque
ncy
Forecast probability
AROME-PEARPAROME-PERTOBS
AROME-COMB
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D23
Precipitation: Ensemble spread
0
2
4
6
8
10
12
14
0 2 4 6 8 10 12 14
RM
SE
Spread
AROME-PEARPAROME-PERTOBS
AROME-COMB
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D24
Ensemble spread for 925hPa wind speed
Rank histograms: a U-shaped histogram shows ensemble underdispersion
0
200000
400000
600000
800000
1e+06
1.2e+06
1.4e+06
1.6e+06
0 2 4 6 8 10 12
AROME-PEARPAROME-PERTOBS
AROME-COMB
3h
0
0.5
1
1.5
2
2.5
3
3.5
4
0 0.5 1 1.5 2 2.5 3 3.5 4
RM
SE
Spread
AROME-PEARPAROME-PERTOBS
AROME-COMB
0
200000
400000
600000
800000
1e+06
1.2e+06
1.4e+06
1.6e+06
0 2 4 6 8 10 12
AROME-PEARPAROME-PERTOBS
AROME-COMB
6h
0
0.5
1
1.5
2
2.5
3
3.5
4
0 0.5 1 1.5 2 2.5 3 3.5 4
RM
SE
Spread
AROME-PEARPAROME-PERTOBS
AROME-COMB
0
200000
400000
600000
800000
1e+06
1.2e+06
1.4e+06
1.6e+06
0 2 4 6 8 10 12
AROME-PEARPAROME-PERTOBS
AROME-COMB
12h
0
0.5
1
1.5
2
2.5
3
3.5
4
0 0.5 1 1.5 2 2.5 3 3.5 4
RM
SE
Spread
AROME-PEARPAROME-PERTOBS
AROME-COMB
0
200000
400000
600000
800000
1e+06
1.2e+06
1.4e+06
1.6e+06
0 2 4 6 8 10 12
AROME-PEARPAROME-PERTOBS
AROME-COMB
24h
0
0.5
1
1.5
2
2.5
3
3.5
4
0 0.5 1 1.5 2 2.5 3 3.5 4
RM
SE
Spread
AROME-PEARPAROME-PERTOBS
AROME-COMB
RMSE vs. Ensemble spread
14th AMS conference on Mesoscale Processes, 1 August 2011, LA | B V, O N, V D25
