training course 2012– nwp-pr: the monthly forecast system at ecmwf 1 monthly forecasting at ecmwf...
TRANSCRIPT
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 1
Monthly Forecasting at ECMWF
Frédéric Vitart European Centre for Medium-Range Weather Forecasts
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 2
Index
• Main sources of predictability on the monthly time-scale
Madden Julian Oscillation Soil Moisture Stratospheric Initial conditions
• The ECMWF monthly forecast system Description Some examples of forecasts Skill
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 3
Product
ECMWF:Weather and Climate Dynamical Forecasts
ECMWF:Weather and Climate Dynamical Forecasts
Medium-Range Forecasts
Day 1-10(15)
Medium-Range Forecasts
Day 1-10(15)
MonthlyForecast
Day 10-32
MonthlyForecast
Day 10-32
Seasonal Forecasts
Month 2-7
Seasonal Forecasts
Month 2-7
Forecasting systems at ECMWF
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 4
• A particularly difficult time range: Is it an atmospheric initial condition problem as medium-range forecasting or is it a boundary
condition problem as seasonal forecasting?
• Some sources of predictability in the monthly time scale:
Sea surface temperature/Sea ice
Snow cover
Soil Moisture
Stratospheric Initial conditions
The Madden-Julian oscillation
Bridging the gap between seasonal forecasting and NWP
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 5 5
Koster et al, GRL 2010
Impact of soil moisture
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 6 6
Koster et al, GRL 2010
Impact of soil moisture
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 7
Stratospheric Sudden Warmings
Chui and Kunz, 2009
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 8
Baldwin and Dunkerton, 2001
Stratospheric influence on the troposphere?
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 9
Z1000 Response
(Weak vortex-CTL)
D+1-D+10 D+11-D+20
D+21-D+30 D+31-D+40
From T. Jung et al 2005
Stratospheric influence on the troposphere?
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 10
Synoptic Z500 Activity D+21-D+30
From T. Jung et al 2005
Stratospheric influence on the troposphere?
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 11
Stratospheric Sudden warming- January 2009
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
Day
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
T50
Gra
dien
t
Mem. Ctr Mean Ana.
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
Day
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
T50
Gra
dien
t
Mem. Ctr Mean Ana.
8/1/2009 15/1/2009SSW Index (T50 gradient)
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 12
Stratospheric Sudden warming- January 2009
15/1/2009 2mtm anomaly Forecast
AnalysisComposite Good SW
Composite Bad SW
30°N 30°N
40°N40°N
50°N 50°N
60°N60°N
20°W
20°W 0°
0° 20°E
20°E
30 30
4040
50 50
6060
20
20 0
0 20
20
Contours at 1% levelShaded areas significant at 10% levelensemble size = 51 ,climate size = 90
Verification period: 02-02-2009/TO/08-02-20092-meter Temperature anomaly
Analysis and ECMWF VarEPS-Monthly Forecasting System
30 30
4040
50 50
6060
20
20 0
0 20
20
30 30
4040
50 50
6060
20
20 0
0 20
20
30 30
4040
50 50
6060
20
20 0
0 20
20
ANALYSIS
FORECAST 29-01-2009: DAY 5-11 FORECAST 22-01-2009: DAY 12-18
FORECAST 15-01-2009: DAY 19-25 FORECAST 08-01-2009: DAY 26-32
<-10deg
-10.. -6
-6.. -3
-3.. -1
-1.. 0
0.. 1
1.. 3
3.. 6
6.. 10
> 10deg
30°N 30°N
40°N40°N
50°N 50°N
60°N60°N
20°W
20°W 0°
0° 20°E
20°E
30 30
4040
50 50
6060
20
20 0
0 20
20
Contours at 1% levelShaded areas significant at 10% levelensemble size = 51 ,climate size = 90
Verification period: 09-02-2009/TO/15-02-20092-meter Temperature anomaly
Analysis and ECMWF VarEPS-Monthly Forecasting System
30 30
4040
50 50
6060
20
20 0
0 20
20
30 30
4040
50 50
6060
20
20 0
0 20
20
30 30
4040
50 50
6060
20
20 0
0 20
20
ANALYSIS
FORECAST 05-02-2009: DAY 5-11 FORECAST 29-01-2009: DAY 12-18
FORECAST 22-01-2009: DAY 19-25 FORECAST 15-01-2009: DAY 26-32
<-10deg
-10.. -6
-6.. -3
-3.. -1
-1.. 0
0.. 1
1.. 3
3.. 6
6.. 10
> 10deg
Day 19-25
Day 26-32
30°N 30°N
40°N40°N
50°N 50°N
60°N60°N
20°W
20°W 0°
0° 20°E
20°E
ensemble size = 51 ,climate size = 90Forecast start reference is 15-01-20092-meter Temperature anomalyECMWF VAREPS-Monthly Forecasting System
Contours at 1% levelShaded areas significant at 10% levelREFDATE1=02-02-2009/TO/08-02-2
Day 19-25
<-10deg -10.. -6 -6.. -3 -3.. -1 -1.. 0 0.. 1 1.. 3 3.. 6 6.. 10 > 10deg
30°N 30°N
40°N40°N
50°N 50°N
60°N60°N
20°W
20°W 0°
0° 20°E
20°E
ensemble size = 51 ,climate size = 90Forecast start reference is 15-01-20092-meter Temperature anomalyECMWF VAREPS-Monthly Forecasting System
Contours at 1% levelShaded areas significant at 10% levelREFDATE1=02-02-2009/TO/08-02-2
Day 19-25
<-10deg -10.. -6 -6.. -3 -3.. -1 -1.. 0 0.. 1 1.. 3 3.. 6 6.. 10 > 10deg
30°N 30°N
40°N40°N
50°N 50°N
60°N60°N
20°W
20°W 0°
0° 20°E
20°E
ensemble size = 51 ,climate size = 90Forecast start reference is 15-01-20092-meter Temperature anomalyECMWF VAREPS-Monthly Forecasting System
Contours at 1% levelShaded areas significant at 10% levelREFDATE1=02-02-2009/TO/08-02-2
Day 19-25
<-10deg -10.. -6 -6.. -3 -3.. -1 -1.. 0 0.. 1 1.. 3 3.. 6 6.. 10 > 10deg
30°N 30°N
40°N40°N
50°N 50°N
60°N60°N
20°W
20°W 0°
0° 20°E
20°E
ensemble size = 51 ,climate size = 90Forecast start reference is 15-01-20092-meter Temperature anomalyECMWF VAREPS-Monthly Forecasting System
Contours at 1% levelShaded areas significant at 10% levelREFDATE1=02-02-2009/TO/08-02-2
Day 19-25
<-10deg -10.. -6 -6.. -3 -3.. -1 -1.. 0 0.. 1 1.. 3 3.. 6 6.. 10 > 10deg
30°N 30°N
40°N40°N
50°N 50°N
60°N60°N
20°W
20°W 0°
0° 20°E
20°E
30 30
4040
50 50
6060
20
20 0
0 20
20
Contours at 1% levelShaded areas significant at 10% levelensemble size = 51 ,climate size = 90
Verification period: 02-02-2009/TO/08-02-20092-meter Temperature anomaly
Analysis and ECMWF VarEPS-Monthly Forecasting System
30 30
4040
50 50
6060
20
20 0
0 20
20
30 30
4040
50 50
6060
20
20 0
0 20
20
30 30
4040
50 50
6060
20
20 0
0 20
20
ANALYSIS
FORECAST 29-01-2009: DAY 5-11 FORECAST 22-01-2009: DAY 12-18
FORECAST 15-01-2009: DAY 19-25 FORECAST 08-01-2009: DAY 26-32
<-10deg
-10.. -6
-6.. -3
-3.. -1
-1.. 0
0.. 1
1.. 3
3.. 6
6.. 10
> 10deg
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 13
From Madden and Julian (1972)
The Madden-Julian Oscillation (MJO)
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 14
The Madden Julian Oscillation (MJO)
From http://www.bom.gov.au/bmrc/clf
MJO life cycle
(From NASA)
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 15
The Madden Julian Oscillation (MJO)
• The MJO is a 40-50-day oscillation
• The MJO is a near-global scale, quasi-periodic eastward moving disturbance in the surface pressure, tropospheric temperature and zonal winds over the equatorial belt.
• The Madden-Julian Oscillation (MJO) is the dominant mode of variability in the tropics in time scales in excess of 1 week but less than 1 season.
• The MJO has its peak activity during Northern winter and spring.
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 16
The Madden Julian Oscillation (MJO)
• Impact on the Indian and Australian summer monsoons (Yasunari 1979), Hendon and Liebman (1990)
• Impact on ENSO. Westerly wind bursts produce equatorial trapped Kelvin waves, which have a significant impact on the onset and development of an El-Niňo event. Kessler and McPhaden (1995)
• Impact on tropical storms (Maloney et al, 2000; Mo, 2000)
• Impact on Northern Hemisphere weather
Why is the MJO so important?
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 17
Figure 12: Vertically averaged anomalous heating rate for (a) Exp1; and (b) Exp2. The
contour interval is0.5 C day- 1. Thezero contour isnot plotted, and contourswith negative
values aredashed.
42
Lin et al, MWR 2010See also
Simmons et al JAS 1983Ting and Sardeshmukh JAS 1993
Impact of the MJO on Extratropics
Figure 12: Vertically averaged anomalous heating rate for (a) Exp1; and (b) Exp2. The
contour interval is0.5 C day- 1. Thezero contour isnot plotted, and contourswith negative
values aredashed.
42
Figure13: 500hPageopotential height responseaveragedbetweenday6and10(left) and
betweenday11and15(right) for Exp1(top) andExp2(bottom). Thecontour interval is
15m. Contourswithnegativevaluesaredashed.
43
Figure13: 500hPageopotential height responseaveragedbetweenday6and10(left) and
betweenday11and15(right) for Exp1(top) andExp2(bottom). Thecontour interval is
15m. Contourswithnegativevaluesaredashed.
43
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 18
MJO Prediction
Combined EOF1
Combined EOF2
From Wheeler and Hendon, BMRC
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 19
MJO FORECAST
-4 -3 -2 -1 0 1 2 3 4
RMM1
-4
-3
-2
-1
0
1
2
3
4
RM
M2
FORECAST BASED 15/05/1997 00UTCECMWF MONTHLY FORECASTS
and AfricaWest Hem.
ContinentMaritime
PacificWestern
OceanIndian
2
1
8
7 6
5
4
3
Day 1 Day 5 Day 10
Day 15 Day 20 Analysis
Ens. Mean Verification
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 20
Impact on Europe
Cassou (2008)
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 21
Experiment’s setting:
- 46 day forecasts at T255L62 coupled to HOPE
- 15 members
- Starting dates: 15 Nov/Dec/Jan/Feb/Mar/Apr 1989-2008
- Model Cycle 32R3 (operational cycle from 11/07 to 06/08)
MJO prediction
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 22
“Perfect Model”
Ensemble mean/ reanalysis
MJO Skill scores
Bivariate Correlation Bivariate RMS error
0 5 10 15 20 25 30 35 40 45Time Lag (days)
0
0.2
0.4
0.6
0.8
1
Correla
tion
Ensemble Spread
0 5 10 15 20 25 30 35 40 45Time Lag (days)
0
0.5
1
1.5
RM
S E
rror
Ensemble mean/ reanalysis
Climatology
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 23
Impact on Precipitation anomalies (Summer)Model Phase 23 ERA Phase 23
Model Phase 45 ERA Phase 45
Model Phase 67 ERA Phase 67
Model Phase 81 ERA Phase 81
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 24
Impact on Tropical Cyclone Density (Summer)
Vitart, GRL 2009
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 25
Impact on the Extratropics- Z500 anomalies
MODEL Phase 3 + 10 days ERA Phase 3 + 10 days
MODEL Phase 6 + 10 days ERA Phase 6 + 10 days
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 26
Impact of MJO on Z500 anomalies
500hPa GeopotentialTuesday 15 January 1991 00UTC ECMWF EPS Control Forecast t+0 VT: Tuesday 15 January 1991 00UTC
-100-95-90-85-80-75-70-65-60-55-50-45-40-35-30-25-20-15-10-5510152025303536.26
500hPa GeopotentialTuesday 15 January 1991 00UTC ECMWF EPS Control Forecast t+0 VT: Tuesday 15 January 1991 00UTC
-100-95-90-85-80-75-70-65-60-55-50-45-40-35-30-25-20-15-10-55101520253035404549.42
500hPa GeopotentialTuesday 15 January 1991 00UTC ECMWF EPS Control Forecast t+0 VT: Tuesday 15 January 1991 00UTC
510152025303540455051.38-100-95-90-85-80-75-70-65-60-55-50-45-40-35-30-25-20-15-10-5
1 std< AMP < 1.5 std AMP > 2 std1.5 std< AMP < 2 std
Interval = 5 metres
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 27
Phase3+10 days
1 2 3 4-30
-20
-10
0
10
20
30
Impact on weather regimes in hindcasts
NAO- NAO+ Atlantic ridge
Scandinavian blocking
Phase6+10 days
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 28
T850 anomalies – NDJFM 1989-2008
Temperature anomalies (degC)
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
50°N50°N
60°N 60°N
70°N70°N
160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W 0°
0° 20°E
20°E 40°E
40°E 60°E
60°E
<-1.6 -1.6..-0.8 -0.8..-0.4 -0.4..-0.2 -0.2.. 0.0 0.0.. 0.2 0.2.. 0.4 0.4.. 0.8 0.8.. 1.6 > 1.6
Temperature anomalies (degC)
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
50°N50°N
60°N 60°N
70°N70°N
160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W 0°
0° 20°E
20°E 40°E
40°E 60°E
60°E
<-1.6 -1.6..-0.8 -0.8..-0.4 -0.4..-0.2 -0.2.. 0.0 0.0.. 0.2 0.2.. 0.4 0.4.. 0.8 0.8.. 1.6 > 1.6
Temperature anomalies (degC)
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
50°N50°N
60°N 60°N
70°N70°N
160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W 0°
0° 20°E
20°E 40°E
40°E 60°E
60°E
<-1.6 -1.6..-0.8 -0.8..-0.4 -0.4..-0.2 -0.2.. 0.0 0.0.. 0.2 0.2.. 0.4 0.4.. 0.8 0.8.. 1.6 > 1.6
Temperature anomalies (degC)
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
50°N50°N
60°N 60°N
70°N70°N
160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W 0°
0° 20°E
20°E 40°E
40°E 60°E
60°E
<-1.6 -1.6..-0.8 -0.8..-0.4 -0.4..-0.2 -0.2.. 0.0 0.0.. 0.2 0.2.. 0.4 0.4.. 0.8 0.8.. 1.6 > 1.6
Phase 3 + 10 days Phase 6 + 10 days
ERA
MODEL
Temperature anomalies (degC)
30°N30°N
40°N 40°N
50°N50°N
60°N 60°N
70°N70°N
160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W 0°
0° 20°E
20°E 40°E
40°E 60°E
60°E
<-1.6 -1.6..-0.8 -0.8..-0.4 -0.4..-0.2 -0.2.. 0.0 0.0.. 0.2 0.2.. 0.4 0.4.. 0.8 0.8.. 1.6 > 1.6 Degree C
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 29
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1forecast probability
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
obs
freq
uen
cy
0.04
Probabilistic skill scores – NDJFMA 1989-2008
Reliability DiagramProbability of 2-m temperature in the upper tercile
Day 19-25
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1forecast probability
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
obs
freq
uen
cy
Europe
0.03
-0.09
MJO in IC NO MJO in IC
N. Extratropics
-0.06
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 30
Impact of the Extratropics on the MJO?
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 31
Impact of N. Extratropics on MJO forecast skill
0 5 10 15 20 25 30 35 40 45Forecast Range (Days)
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Corr
ela
tion
MJO index Correlation
Relax to OBS.
Relax to IC
Control
Vitart and Jung
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 32
Relaxed to Initial Conditions
Relaxed to Observations
ControlObs.
March 1997 Westerly Wind Burst -U850
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
-20
-25
-30
DAY
S
30E 90E 150E 150W 90W 30WLONGITUDE
30E 90E 150E 150W 90W 30W
FORECAST BASED 15/2/1997 00UTCENSEMBLE MEAN BETWEEN LAT 15S AND 15N
Zonal wind anomaly at 850 hPaHOVMOLLER DIAGRAM OF MONTHLY FORECAST
1
1
-1
1/04
30/03
28/03
26/03
24/03
22/03
20/03
18/03
16/03
14/03
12/03
10/03
8/03
6/03
4/03
2/03
28/02
26/02
24/02
22/02
20/02
18/02
16/02
14/02
12/02
10/02
8/02
6/02
4/02
2/02
31/01
29/01
27/01
25/01
23/01
21/01
19/01
17/01
15/01
FO
REC
AST
A
NAL
YSIS
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
-20
-25
-30
DAYS
30E 90E 150E 150W 90W 30WLONGITUDE
30E 90E 150E 150W 90W 30W
FORECAST BASED 15/2/1997 00UTCENSEMBLE MEAN BETWEEN LAT 15S AND 15N
Zonal wind anomaly at 850 hPaHOVMOLLER DIAGRAM OF MONTHLY FORECAST
1/04
30/03
28/03
26/03
24/03
22/03
20/03
18/03
16/03
14/03
12/03
10/03
8/03
6/03
4/03
2/03
28/02
26/02
24/02
22/02
20/02
18/02
16/02
14/02
12/02
10/02
8/02
6/02
4/02
2/02
31/01
29/01
27/01
25/01
23/01
21/01
19/01
17/01
15/01
FO
RECA
ST
AN
ALYS
IS
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
-20
-25
-30DA
YS
30E 90E 150E 150W 90W 30WLONGITUDE
30E 90E 150E 150W 90W 30W
FORECAST BASED 15/2/1997 00UTCENSEMBLE MEAN BETWEEN LAT 15S AND 15N
Zonal wind anomaly at 850 hPaHOVMOLLER DIAGRAM OF MONTHLY FORECAST
5
-1
1/04
30/03
28/03
26/03
24/03
22/03
20/03
18/03
16/03
14/03
12/03
10/03
8/03
6/03
4/03
2/03
28/02
26/02
24/02
22/02
20/02
18/02
16/02
14/02
12/02
10/02
8/02
6/02
4/02
2/02
31/01
29/01
27/01
25/01
23/01
21/01
19/01
17/01
15/01
FO
RECA
ST
AN
ALYS
IS
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
-20
-25
-30
DAYS
30E 90E 150E 150W 90W 30WLONGITUDE
30E 90E 150E 150W 90W 30W
FORECAST BASED 15/2/1997 00UTCENSEMBLE MEAN BETWEEN LAT 15S AND 15N
Zonal wind anomaly at 850 hPaHOVMOLLER DIAGRAM OF MONTHLY FORECAST
1
1/04
30/03
28/03
26/03
24/03
22/03
20/03
18/03
16/03
14/03
12/03
10/03
8/03
6/03
4/03
2/03
28/02
26/02
24/02
22/02
20/02
18/02
16/02
14/02
12/02
10/02
8/02
6/02
4/02
2/02
31/01
29/01
27/01
25/01
23/01
21/01
19/01
17/01
15/01 F
ORE
CAST
ANAL
YSIS
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 33
The ECMWF monthly forecasting system
• A 51-member ensemble is integrated for 32 days twice a week (Mondays and Thursdays at 00Z)
• Atmospheric component: IFS with the latest operational cycle and with a T639L62 resolution till day 10 and T319L62 after day 10.
• Persisted SST anomalies till day 10 and ocean-atmosphere coupling from day 10 till day 32.
• Oceanic component: HOPE (from Max Plank Institute) with a zonal resolution of 1.4 degrees and 29 vertical levels
• Coupling: OASIS (CERFACS). Coupling every 3 hours.
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 34
Ocean only integration
Coupled forecast at TL319Day 32
EPS Integration at T639
Initial condition
Heat flux, Wind stress, P-E
Day 10
The ECMWF VarEPS-monthly forecasting system
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 35
The ECMWF monthly forecasting system
• Atmospheric initial conditions: ECMWF operational analysis
• Oceanic initial conditions: “Accelerated” ocean analysis
• Perturbations: Atmosphere: Singular vectors + stochastic physics
Ocean: Wind stress perturbations during the data assimilation
• Background statistics:
5-member ensemble integrated at the same day and same month as the real-time time forecast over the past 18 years (a total of 90 member ensemble). Initial conditions: ERA Interim. Produced once a week.
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 36
The ECMWF monthly forecasting system
Anomalies (temperature, precipitation..)
-
80°S 80°S70°S70°S
60°S 60°S
50°S50°S40°S 40°S
30°S30°S
20°S 20°S10°S10°S
0° 0°
10°N10°N
20°N 20°N30°N30°N
40°N 40°N
50°N50°N60°N 60°N
70°N70°N
80°N 80°N
160°W
160°W
120°W
120°W
80°W
80°W
40°W
40°W
0°
0° 20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E
120°E
120°E
160°E
160°E
ensemble size = 51 ,climate size = 90Forecast start reference is 05-05-20112-meter Temperature anomalyECMWF EPS-Monthly Forecasts
Contours at 1% levelShaded areas significant at 10% level
80°S 80°S70°S70°S
60°S 60°S
50°S50°S40°S 40°S
30°S30°S
20°S 20°S10°S10°S
0° 0°
10°N10°N
20°N 20°N30°N30°N
40°N 40°N
50°N50°N60°N 60°N
70°N70°N
80°N 80°N
160°W
160°W
120°W
120°W
80°W
80°W
40°W
40°W
0°
0° 20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E
120°E
120°E
160°E
160°E
80°S 80°S
70°S70°S60°S 60°S
50°S50°S
40°S 40°S30°S30°S
20°S 20°S
10°S10°S
0° 0°10°N10°N
20°N 20°N
30°N30°N40°N 40°N
50°N50°N
60°N 60°N70°N70°N
80°N 80°N
160°W
160°W
120°W
120°W
80°W
80°W
40°W
40°W
0°
0° 20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E
120°E
120°E
160°E
160°E
80°S 80°S
70°S70°S60°S 60°S
50°S50°S
40°S 40°S30°S30°S
20°S 20°S
10°S10°S
0° 0°10°N10°N
20°N 20°N
30°N30°N40°N 40°N
50°N50°N
60°N 60°N70°N70°N
80°N 80°N
160°W
160°W
120°W
120°W
80°W
80°W
40°W
40°W
0°
0° 20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E
120°E
120°E
160°E
160°E
DAY 5-11: 09-05-2011/TO/15-05-2011 DAY 12-18 :16-05-2011/TO/22-05-2011
DAY 19-25 :23-05-2011/TO/29-05-2011 DAY 26-32:30-05-2011/TO/05-06-2011
<-10deg -10.. -6 -6.. -3 -3.. -1 -1.. 0 0.. 1 1.. 3 3.. 6 6.. 10 > 10deg
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 37
The ECMWF monthly forecasting system
Probabilities (temperature, precipitation..)
-
80°S 80°S
70°S70°S
60°S 60°S
50°S50°S
40°S 40°S
30°S30°S
20°S 20°S
10°S10°S
0° 0°
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
50°N50°N
60°N 60°N
70°N70°N
80°N 80°N
160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W 0°
0° 20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E
ensemble size = 51 ,climate size = 90Forecast start reference is 05-05-2011Prob(2-meter Temp. anom gt 0)ECMWF EPS-Monthly Forecasts
Contours at 1% levelShaded areas significant at 10% level
16-05-2011/TO/22-05-2011Day 12-18
< 10% 10.. 20 20.. 30 30.. 40 40.. 60 60.. 70 70.. 80 80.. 90 > 90%
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 38
The ECMWF monthly forecasting system
H
L
L
L
L
40°N
60°N
80°N80°W
80°W
60°W
40°W
20°W 0° 20°E
40°E
60°E
80°E
80°E
Reg 1 ** Cluster mean (6)05-05-2011 week2 : step 264-432
H
LL
L
40°N
60°N
80°N80°W
80°W
60°W
40°W
20°W 0° 20°E
40°E
60°E
80°E
80°E
Reg 2 ** Cluster mean (8)05-05-2011 week2 : step 264-432
L
40°N
60°N
80°N80°W
80°W
60°W
40°W
20°W 0° 20°E
40°E
60°E
80°E
80°E
Reg 3 ** Cluster mean (8)05-05-2011 week2 : step 264-432
L
560
40°N
60°N
80°N80°W
80°W
60°W
40°W
20°W 0° 20°E
40°E
60°E
80°E
80°E
Reg 4 ** Cluster mean (11)05-05-2011 week2 : step 264-432
L
L
40°N
60°N
80°N80°W
80°W
60°W
40°W
20°W 0° 20°E
40°E
60°E
80°E
80°E
Reg 5 ** Cluster mean (12) - CTR05-05-2011 week2 : step 264-432
L L
572
40°N
60°N
80°N80°W
80°W
60°W
40°W
20°W 0° 20°E
40°E
60°E
80°E
80°E
Reg 6 ** Cluster mean (5)05-05-2011 week2 : step 264-432
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 39
Experimental product: Tropical cyclone activity
The ECMWF monthly forecasting system
80°N
70°N
60°N
50°N
40°N
30°N
20°N
10°N
0°N
10°S
20°S
30°S
40°S
50°S
60°S
70°S
80°S
80°N
70°N
60°N
50°N
40°N
30°N
20°N
10°N
0°N
10°S
20°S
30°S
40°S
50°S
60°S
70°S
80°S
340°E320°E300°E280°E260°E240°E220°E200°E180°E160°E140°E120°E100°E80°E60°E40°E20°E
340°E320°E300°E280°E260°E240°E220°E200°E180°E160°E140°E120°E100°E80°E60°E40°E20°E
< 10% 10.. 20 20.. 30 30.. 40 40.. 50 50.. 60 60.. 70 70.. 80 80.. 90 > 90%
Probability of a TC passing within 300km radiusWeekly Mean Tropical Cyclone Strike Probability. Date: 20100408 0 UTC t+(264-432)
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 40
MJO Forecasts
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 41 41
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
Contours at 1% levelShaded areas significant at 10% levelensemble size = 51 ,climate size = 90
Verification period: 26-07-2010/TO/01-08-2010Precipitation anomaly
Analysis and ECMWF VarEPS-Monthly Forecasting System
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
ANALYSIS
FORECAST 22-07-2010: DAY 5-11 FORECAST 15-07-2010: DAY 12-18
FORECAST 08-07-2010: DAY 19-25 FORECAST 01-07-2010: DAY 26-32
<-90mm
-90..-60
-60..-30
-30..-10
-10.. 0
0.. 10
10.. 30
30.. 60
60.. 90
> 90mm
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
Contours at 1% levelShaded areas significant at 10% levelensemble size = 51 ,climate size = 90
Verification period: 26-07-2010/TO/01-08-2010Precipitation anomaly
Analysis and ECMWF VarEPS-Monthly Forecasting System
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
ANALYSIS
FORECAST 22-07-2010: DAY 5-11 FORECAST 15-07-2010: DAY 12-18
FORECAST 08-07-2010: DAY 19-25 FORECAST 01-07-2010: DAY 26-32
<-90mm
-90..-60
-60..-30
-30..-10
-10.. 0
0.. 10
10.. 30
30.. 60
60.. 90
> 90mm
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
Contours at 1% levelShaded areas significant at 10% levelensemble size = 51 ,climate size = 90
Verification period: 26-07-2010/TO/01-08-2010Precipitation anomaly
Analysis and ECMWF VarEPS-Monthly Forecasting System
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
ANALYSIS
FORECAST 22-07-2010: DAY 5-11 FORECAST 15-07-2010: DAY 12-18
FORECAST 08-07-2010: DAY 19-25 FORECAST 01-07-2010: DAY 26-32
<-90mm
-90..-60
-60..-30
-30..-10
-10.. 0
0.. 10
10.. 30
30.. 60
60.. 90
> 90mm
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
Contours at 1% levelShaded areas significant at 10% levelensemble size = 51 ,climate size = 90
Verification period: 26-07-2010/TO/01-08-2010Precipitation anomaly
Analysis and ECMWF VarEPS-Monthly Forecasting System
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
ANALYSIS
FORECAST 22-07-2010: DAY 5-11 FORECAST 15-07-2010: DAY 12-18
FORECAST 08-07-2010: DAY 19-25 FORECAST 01-07-2010: DAY 26-32
<-90mm
-90..-60
-60..-30
-30..-10
-10.. 0
0.. 10
10.. 30
30.. 60
60.. 90
> 90mm
Precip anomalies : 26 July 2010 – 01 August 2010
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
Contours at 1% levelShaded areas significant at 10% levelensemble size = 51 ,climate size = 90
Verification period: 26-07-2010/TO/01-08-2010Precipitation anomaly
Analysis and ECMWF VarEPS-Monthly Forecasting System
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
40°E
40°E 60°E
60°E 80°E
80°E
ANALYSIS
FORECAST 22-07-2010: DAY 5-11 FORECAST 15-07-2010: DAY 12-18
FORECAST 08-07-2010: DAY 19-25 FORECAST 01-07-2010: DAY 26-32
<-90mm
-90..-60
-60..-30
-30..-10
-10.. 0
0.. 10
10.. 30
30.. 60
60.. 90
> 90mm
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 42
Skill of the ECMWF Monthly Forecasting System
ROC score: 2-meter temperature in the upper tercile
Day 19-25 Day 26-32
Day 5-11 Day 12-18
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 43
Skill of the ECMWF Monthly Forecasting System
2-meter temperature in upper tercile - Day 12-18ROC score Reliability diagram
Persistence of day 5-11
Monthly forecast day 12-18
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1false alarm rate
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
hit
rat
eDay 1220041007-20041007
ECMWF Monthly Forecast, 2mtm in upper tercile , Area:Northern Extratropics
ROC score = 0.676ROC score = 0.620
0 0.2 0.4 0.6 0.8 1rel FC distribution
78450.157 10
5
0.235 105
0.314 105
0.392 105
Forecast
Persistence
0.2
0.2
0.4
0.4
0.4
0.4
0.6
0.6
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1forecast probability
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
ob
s fr
equ
ency
8381
40918
50188
53110
50696
43197
33901
24064
14983
8618
4660
62697
60112
3110423795
20433 1866617728
1753018151
19773
42727
Day 5-20041007-20041007ECMWF Monthly Forecast, 2-meterin upper tercile , Area:Northern Extratropics
BrSc = 0.211 LCBrSkSc= 0.06 Uncertainty= 0.223BrSc = 0.283 LCBrSkSc= -0.27 Uncertainty= 0.223
0 0.2 0.4 0.6 0.8 1rel FC distribution
0
0.2
0.4
0.6
0.8
1
B(S)S_REL= 0.008 ( 0.96)B(S)S_RSL= 0.020 ( 0.09)
sample clim
clim 1990-2001
Forecast Persistence
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1false alarm rate
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
hit
rat
e
Day 1920041007-20041007ECMWF Monthly Forecast, 2mtm in upper tercile , Area:Northern Extratropics
ROC score = 0.605ROC score = 0.567
0 0.2 0.4 0.6 0.8 1rel FC distribution
98200.196 10
5
0.295 105
0.393 105
0.491 105
Forecast
Persistence
0.2
0.2
0.4
0.4
0.4
0.4
0.6
0.6
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1forecast probability
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
ob
s fr
equ
ency
2333
18918
44209
68632
74515
60695
37194
17750
6448
1736
286
34211
6006540040 32847
29053 26408 2441722690
2024518904
23836
Day 5-20041007-20041007ECMWF Monthly Forecast, 2-meterin upper tercile , Area:Northern Extratropics
BrSc = 0.224 LCBrSkSc= 0.00 Uncertainty= 0.225BrSc = 0.287 LCBrSkSc= -0.27 Uncertainty= 0.225
0 0.2 0.4 0.6 0.8 1rel FC distribution
0
0.2
0.4
0.6
0.8
1
B(S)S_REL= 0.008 ( 0.97)B(S)S_RSL= 0.007 ( 0.03)
sample clim
clim 1990-2001
Forecast Persistence
Day 12-18
Day 19-25
Persistence of day 5-18
Monthly forecast day 19-32
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 44
OLR anomalies - Forecast range: day 15
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 45
MJO skill scores
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
Fore
cast D
ay
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
YEAR
MJO Bivariate Correlation
0.5 0.6 0.8
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 46
NAO skill scores
0.4
0.5
0.6
Fore
cast
Day
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
YEAR
MJO Bivariate Correlation
0.5
2004 2006 2008 2010 20120.3
0.4
0.5
0.6
0.7
0.8
All cases NDJFM NDJFM
MJO in IC
NO MJO in IC
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 47
Performance of the monthly Forecasts
Day 12-18 Day 19-25 Day 26-32
2005 2006 2007 2008 2009 2010 2011YEAR
0.5
0.55
0.6
0.65
0.7
0.75
0.8
RO
C A
rea
2-metre temperature ROC area over Northern Extratropics
Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 48
Conclusion
• SSTs, Soil moisture, stratospheric initial conditions and MJO are source of
predictability at the intra-seasonal time scale. In particular the MJO has a significant
impact on the forecast skill scores beyond day 20. Model improvements, particularly
in simulating the MJO activity are likely to be beneficial for monthly forecasting.
• The monthly forecasting system produces forecasts for days 12-18 that are
generally better than climatology and persistence of day 5-11. Beyond day 20, the
monthly forecast is marginally skilful. For some applications and some regions,
these forecasts could however be of some interest. There has been a clear
improvement in the monthly forecast skill scores over the past 10 years. This
improvement is likely to be related to improved prediction in the Tropics and most
especially improved MJO prediction.
•