Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 1 Monthly Forecasting at ECMWF Frédéric Vitart European Centre for Medium-Range Weather.

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


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


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


• 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


Koster et al, GRL 2010

Impact of soil moisture


Stratospheric Sudden Warmings

Chui and Kunz, 2009


Baldwin and Dunkerton, 2001

Stratospheric influence on the troposphere?


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



Synoptic Z500 Activity D+21-D+30

From T. Jung et al 2005



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)


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


<-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




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



<-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



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



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



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




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



<-10deg

-10.. -6

-6.. -3

-3.. -1

-1.. 0

0.. 1

1.. 3

3.. 6

6.. 10

> 10deg


From Madden and Julian (1972)

The Madden-Julian Oscillation (MJO)


The Madden Julian Oscillation (MJO)

From http://www.bom.gov.au/bmrc/clf

MJO life cycle

(From NASA)



• 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.



• 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?


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


MJO Prediction

Combined EOF1

Combined EOF2

From Wheeler and Hendon, BMRC


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


Impact on Europe

Cassou (2008)


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


“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


Impact on Precipitation anomalies (Summer)Model Phase 23 ERA Phase 23

Model Phase 45 ERA Phase 45




Impact on Tropical Cyclone Density (Summer)

Vitart, GRL 2009


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


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


-100-95-90-85-80-75-70-65-60-55-50-45-40-35-30-25-20-15-10-55101520253035404549.42


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


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


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


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


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


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


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


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

1

obs

freq

uen

cy

Europe

0.03

-0.09

MJO in IC NO MJO in IC

N. Extratropics

-0.06


Impact of the Extratropics on the MJO?


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


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 30W



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 30W



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 30W



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


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.


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



• 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.



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



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%



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


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


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


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



Experimental product: Tropical cyclone activity


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)


MJO Forecasts


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


Verification period: 26-07-2010/TO/01-08-2010Precipitation anomaly


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



<-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




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



<-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




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



<-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




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



<-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




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



<-90mm

-90..-60

-60..-30

-30..-10

-10.. 0

0.. 10

10.. 30

30.. 60

60.. 90

> 90mm


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


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

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

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


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

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

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


OLR anomalies - Forecast range: day 15


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


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


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


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.

•

Training Course 2012– NWP-PR: The Monthly Forecast System at ECMWF 1 Monthly Forecasting at ECMWF Frédéric Vitart European Centre for Medium-Range Weather.

Documents

ecmwf slide

nwp slide

training course

mjo forecast slide

monthly forecast day

monthly forecasting

product ecmwf

mjo prediction slide