training course 2013– nwp-pr: the monthly forecast system at ecmwf 1 monthly forecasting at ecmwf...
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Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 1
Monthly Forecasting at ECMWF
Frédéric Vitart European Centre for Medium-Range Weather Forecasts
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 2
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 3
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 2013– 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 :
Sea surface temperatures
Land surface conditions: snow-soil moisture
The Madden Julian Oscillation
Stratospheric variability
Atmospheric dynamical processes (Rossby wave propagations, weather regimes…)
Sea ice cover –thickness ?
Bridging the gap between Climate and weather prediction
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 5 5
Koster et al, GRL 2011
Impact of soil moisture
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 6
Stratospheric Sudden Warmings
Chui and Kunz, 2009
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 7
Baldwin and Dunkerton, 2001
Stratospheric influence on the troposphere?
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 8
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 9
Synoptic Z500 Activity D+21-D+30
From T. Jung et al 2005
Stratospheric influence on the troposphere?
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 10
From Madden and Julian (1972)
The Madden-Julian Oscillation (MJO)
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 11
The Madden Julian Oscillation (MJO)
From http://www.bom.gov.au/bmrc/clf
MJO life cycle
(From NASA)
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 12
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 13
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 14
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 15
MJO Prediction
Combined EOF1
Combined EOF2
From Wheeler and Hendon, BMRC
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 16
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 17
Impact on Europe
Cassou (2008)
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 18
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 19
“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 2013– NWP-PR: The Monthly Forecast System at ECMWF 20
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 21
Impact on Tropical Cyclone Density (Summer)
Vitart, GRL 2009
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 22
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 23
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 24
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 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
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 26
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 27
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 28
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 20 years (a total of 100 member ensemble). Initial conditions: ERA Interim. Produced once a week.
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 29
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 30
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 31
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 32
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 33
MJO Forecasts
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 34 34
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 35
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 36
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 37
OLR anomalies - Forecast range: day 15
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 38
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 2013– NWP-PR: The Monthly Forecast System at ECMWF 39
Impact of the MJO on the N. Extratropics
System = 2 - Method = 1 - Ensemble number = 4Friday 27 March 1998 00UTC ECMWF Monthly Forecast t+636 VT: Wednesday 22 April 1998 12UTC 500hPa Geopotential
2002 MOFC hindcasts
2012 MOFC hindcasts
ECMWF Analysis VT:Thursday 23 April 2009 00UTC 500hPa Geopotential
ERA Interim
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 40
NAO skill scores – Day 19-25
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 41
Performance of the monthly Forecasts
Day 12-18 Day 19-25 Day 26-32
2-metre temperature ROC area over Northern Extratropics
Training Course 2013– NWP-PR: The Monthly Forecast System at ECMWF 42
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.
• 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.
•