Monthly Forecasting with Ensembles

Exeter 1-3 December 2010

Monthly Forecasting with Ensembles

Frédéric Vitart European Centre for Medium-Range Weather Forecasts


Index

• The ECMWF monthly forecasting system Description Skill

• Some sources of predictability in the subseasonal time-scale Madden Julian Oscillation Stratospheric Sudden Warming Soil moisture

• Extension to 46-day – Comparison with seasonal forecasts


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


Ocean only integration

Coupled forecast at TL319Day 32

EPS Integration at T639

Initial condition

Heat flux, Wind stress, P-E

Current system (once a week, 51 ensemble members):

The ECMWF VarEPS-monthly forecasting system

Day 10


The ECMWF monthly forecasting system

• 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

It runs once every week


The ECMWF monthly forecasting system

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

70°N 70°N

20°W

20°W 0°

0° 20°E

20°E 40°E

40°E

ensemble size = 51 ,climate size = 90Forecast start reference is 25-11-2010(Prob 2m Temp. anom below 33%)ECMWF EPS-Monthly Forecasts

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

70°N 70°N

20°W

20°W 0°

0° 20°E

20°E 40°E

40°E

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

70°N 70°N

20°W

20°W 0°

0° 20°E

20°E 40°E

40°E

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

70°N 70°N

20°W

20°W 0°

0° 20°E

20°E 40°E

40°E

DAY 5-11: 29-11-2010/TO/05-12-2010 DAY 12-18 :06-12-2010/TO/12-12-2010

DAY 19-25 :13-12-2010/TO/19-12-2010 DAY 26-32:20-12-2010/TO/26-12-2010

< 10% 10.. 20 20.. 40 40.. 50 50.. 60 60.. 70 > 70%

Exeter 1-3 December 2010 7

Problem with hindcast initial conditions

Probability of T2m to be in lowest tercile

100 %0

Forecast of week 1Start: 11-05-2006

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006YEAR

0

0.005

0.01

0.015

Sno

w d

epth

in m

eter

s

SNOW DEPTH (m)0-10E, 40N-50N

Snow ANALYSIS 11 MAY

Observations


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

80°S80°S

70°S 70°S

60°S60°S

50°S 50°S

40°S40°S

30°S 30°S

20°S20°S

10°S 10°S

0°0°

10°N 10°N

20°N20°N

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

70°N 70°N

80°N80°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

20041007 TO 20090205DAY 12-18ROC SCORE : 2-meter temperature in upper tercileECMWF Monthly Forecasting System

<0.1 0.1..0.2 0.2..0.3 0.3..0.4 0.4..0.5 0.5..0.6 0.6..0.7 0.7..0.8 0.8..0.9 > 0.9

80°S80°S

70°S 70°S

60°S60°S

50°S 50°S

40°S40°S

30°S 30°S

20°S20°S

10°S 10°S

0°0°

10°N 10°N

20°N20°N

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

70°N 70°N

80°N80°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


<0.1 0.1..0.2 0.2..0.3 0.3..0.4 0.4..0.5 0.5..0.6 0.6..0.7 0.7..0.8 0.8..0.9 > 0.9

80°S80°S

70°S 70°S

60°S60°S

50°S 50°S

40°S40°S

30°S 30°S

20°S20°S

10°S 10°S

0°0°

10°N 10°N

20°N20°N

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

70°N 70°N

80°N80°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


<0.1 0.1..0.2 0.2..0.3 0.3..0.4 0.4..0.5 0.5..0.6 0.6..0.7 0.7..0.8 0.8..0.9 > 0.9

80°S80°S

70°S 70°S

60°S60°S

50°S 50°S

40°S40°S

30°S 30°S

20°S20°S

10°S 10°S

0°0°

10°N 10°N

20°N20°N

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

70°N 70°N

80°N80°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


<0.1 0.1..0.2 0.2..0.3 0.3..0.4 0.4..0.5 0.5..0.6 0.6..0.7 0.7..0.8 0.8..0.9 > 0.9

80°S80°S

70°S 70°S

60°S60°S

50°S 50°S

40°S40°S

30°S 30°S

20°S20°S

10°S 10°S

0°0°

10°N 10°N

20°N20°N

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

70°N 70°N

80°N80°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


<0.1 0.1..0.2 0.2..0.3 0.3..0.4 0.4..0.5 0.5..0.6 0.6..0.7 0.7..0.8 0.8..0.9 > 0.9


Monthly Forecast: Performance over the Northern Extratropics

Forecast Day 12-18

Persistence of Day 5-11

Forecast Day 19-32

Persistence of Day 5-18

ROC score: 2-meter temperature in the upper tercile

2005 2006 2007 2008 2009 2010YEAR

0.4

0.5

0.6

0.7

0.8

RO

C S

Cor

e

2005 2006 2007 2008 2009 2010YEAR

0.4

0.5

0.6

0.7

0.8

RO

C S

Cor

e

Day 12-18 Day 19-32


The Madden Julian Oscillation


OLR anomalies - Forecast range: day 15

32R3

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

ERA40

10

-10

-1 0 -10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanewku

-10

-10

-10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanex6i

-10

-10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

ERA40

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

ERA40

10

-10

-10

-10

-10 -10-10

-10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanewku

10

-10

-10

-10

-10

-10

-10

-10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanex6i

-10

-10

-10

-10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

days

29/12

05/01

12/01

20/01

28/01

04/04

12/02

28R3 29R1 31R1 32R2

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

ERA40

10

-10

-10

-10

-10 -10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanewku

-10

-10

-10

-10

-10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanex6i

-10

-10

-10

-10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

ERA40

10

-10

-10

-10

-10 -10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanelz5

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanek7h

-10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

ERA40

10

-10

-10

-10

-10 -10-10

-10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanelz5

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanek7h

-10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/02

31/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/01

31/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

ERA40

10

-10

-10

-10

-10 -10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/0231/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/0131/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanes8c

-10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/0231/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/0131/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meaner98

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/0231/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/0131/1230/1229/12

10/04 04/05 09/06 06/07

11/07

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

ERA40

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/0231/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/0131/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanf4i5

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/0231/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/0131/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanf1xi

10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/0231/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/0131/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

ERA40

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/0231/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/0131/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanf4i5

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/0231/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/0131/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanf1xi

10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/0231/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/0131/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

ERA40

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/0231/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/0131/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanf46n

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/0231/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/0131/1230/1229/12

30

25

20

15

10

5

0

DA

YS

30E 90E 150E 150W 90W 30W

LONGITUDE

30E 90E 150E 150W 90W 30W

Ensemble meanf6ju

10

-10

-10

-10

15/0214/0213/0212/0211/0210/02 9/02 8/02 7/02 6/02 5/02 4/02 3/02 2/02 1/0231/0130/0129/0128/0127/0126/0125/0124/0123/0122/0121/0120/0119/0118/0117/0116/0115/0114/0113/0112/0111/0110/01 9/01 8/01 7/01 6/01 5/01 4/01 3/01 2/01 1/0131/1230/1229/12

33R1 35R1 35R3

06/08 09/08 09/09


Experimental setup:

- 46 day hindcasts at T399/T255. Coupled after day 10.

- 15 members

- Starting dates: 1st of each month 1989-2008

- Model Cycle 32R3 (operational cycle from 11/07 to 06/08)

Hindcast Experiment


“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 the Extratropics- Z500 anomalies

MODEL Phase 3 + 10 days ERA Phase 3 + 10 days

MODEL Phase 6 + 10 days ERA Phase 6 + 10 days


500hPa GeopotentialTuesday 15 January 1991 00UTC ECMWF EPS Control Forecast t+0 VT: Tuesday 15 January 1991 00UTC

-100-95-90-85-80-75-70-65-60-55-50-45-40-35-30-25-20-15-10-551015202530354041.19


-100-95-90-85-80-75-70-65-60-55-50-45-40-35-30-25-20-15-10-55101520253035404548.11

ECMWF Analysis VT:Friday 15 November 1991 00UTC 500hPa Geopotential

-100-95-90-85-80-75-70-65-60-55-50-45-40-35-30-25-20-15-10-551015202530354041.48


-100-95-90-85-80-75-70-65-60-55-50-45-40-35-30-25-20-15-10-551015202526.89

ERA Interim 32R3

36R1 36R1_relax

Impact on the Extratropics- Z500 anomalies


Phase3+10 days

1 2 3 4-30

-20

-10

0

10

20

30

Impact on weather regimes

NAO- NAO+ Atlantic ridge

Scandinavian blocking

Phase6+10 days


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

Strong MJO in IC Weak MJO in IC

N. Extratropics

-0.06


Impact of the MJO on Brier Skill ScoresNDJFMA 1989-2008- N. Extratropics

0 1 2 3 40

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

MAGICS 6.12 vancleef - nec Fri Aug 27 11:38:51 2010

DAY 5-11

Z500 T850 Precip

DAY 12-18

Z500 T850 Precip

DAY 19-25 DAY 26-32

0 1 2 3 4-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

MAGICS 6.12 vancleef - nec Fri Aug 27 12:56:10 2010Z500 T850 Precip Z500 T850 Precip0 1 2 3 4

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04


0 1 2 3 4

-0.08

-0.04

0

0.04

0.08

0.12

0.16

0.2


Weak MJO in IC Strong MJO in IC


MJO Composite- NDJFMA

Tropical storm density anomaly

Vitart, 2009, GRL


Tropical storm strike probability

WEEK 1 Week 2 Week 3

Weak MJO 0.78 0.72 0.68

Strong MJO 0.87 0.79 0.74

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


< 10% 10.. 20 20.. 30 30.. 40 40.. 50 50.. 60 60.. 70 70.. 80 80.. 90 > 90%

Probability of a TS passing within 300km radiusWeekly mean Tropical Storm Strike Probability. Date: 20101122 0 UTC t+( 96-264)

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



< 10% 10.. 20 20.. 30 30.. 40 40.. 50 50.. 60 60.. 70 70.. 80 80.. 90 > 90%

Probability of a TS passing within 300km radiusWeekly mean Tropical Storm Strike Probability. Date: 20101122 0 UTC t+(264-432)

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



< 10% 10.. 20 20.. 30 30.. 40 40.. 50 50.. 60 60.. 70 70.. 80 80.. 90 > 90%


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



< 10% 10.. 20 20.. 30 30.. 40 40.. 50 50.. 60 60.. 70 70.. 80 80.. 90 > 90%


ROC AREA over SH

Day 5-11 Day 12-18

Day 19-25 Day 26-32

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



< 10% 10.. 20 20.. 30 30.. 40 40.. 50 50.. 60 60.. 70 70.. 80 80.. 90 > 90%

Probability of a TS passing within 300km radiusWeekly mean Tropical Storm Strike Probability. Date: 20101122 0 UTC t+( 96-264)


Impact of ocean-atmosphere coupling

Figure 4: Correlation of the observed RMM1 and RMM2 timeseries with the ensemblemean forecast timeseries, based on 47 start dates, for the control experiment, CONT(solid line), the mixed layer experiment, ML (dashed line) and the persisted SST ex-periment, PERS (dotted line).

26

Woolnough et al, QJRMS, 2007

Per. SST anomalies

ML

OGCM


Soil Moisture Initial Conditions


GLACE2 Series 1 – Series 2 – ECMWF AMIP

DAY 0-15 DAY 16-30 DAY 31-45

Courtesy Bart van den Hurk


Stratospheric initial conditions


Stratospheric Sudden Warmings

Impact of vertical resolution

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

30T

50 G

radi

ent

L91 Mean L91 L62 Mean L62 Ana..

0 5 10 15 20 25 300

2

4

6

8

10

Spread L91

RMS error L91RMS error L62

Spread L62

Forecast starting on

5/1/06

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 G

radie

nt

L91 Mean L91 L62 Mean L62 Ana.

Forecast starting on

19/1/06

L91 L62


Impact of Better stratospheric vertical resolution

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

rate

week2 19961115-20071115ECMWF Monthly Forecast, Z500 upper tercile , Area:Northern Extratropics

ROC score = 0.737ROC score = 0.734

0 0.2 0.4 0.6 0.8 1rel FC distribution

41858370

0.126 105

0.167 105

0.209 105

f9np

f71f

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 r

ate

week3 19961115-20071115ECMWF Monthly Forecast, Z500 upper tercile , Area:Northern Extratropics



40108020

0.120 105

0.160 105

0.201 105

f9np

f71f

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 r

ate

week4 19961115-20071115ECMWF Monthly Forecast, 2mtm upper tercile , Area:Northern Extratropics



43508700

0.131 105

0.174 105

0.218 105

f9np

f71f

Day 12-18 Day 19-25 Day 26-32

62 levels 91 levels

Probability that Z500 anomalies are in upper tercile1st Feb/May/Aug/Oct 1989-2008 (80 cases)


Stratospheric Sudden Warmings

Impact of S-Svs

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

S-SVs Mean S-SVs L62 Mean L62 Ana.

Forecast 5/01/06

Forecast26/01/06

Ensemble spread

Control S-Svs

5 10 15 20 25 30Time in days

0

1

2

3

4

5

6

Sp

rea

d

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

S-SVs Mean S-SVs L62 Mean L62 Ana.

Work with J. Barkmeijer, T. Jung and M. Leutbecher


46-day EPS experimentComparison with System 3


Global Scores

2MTM- Ensemble mean correlation with analysis

August 1981-2007

June 2MTM

80°S80°S

70°S 70°S

60°S60°S

50°S 50°S

40°S40°S

30°S 30°S

20°S20°S

10°S 10°S

0°0°

10°N 10°N

20°N20°N

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

70°N 70°N

80°N80°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

<0.2 0.2..0.3 0.3..0.4 0.4..0.5 0.5..0.6 0.6..0.7 0.7..0.8 0.8..0.9 0.9..0.95 > 0.95

June 2MTM

80°S80°S

70°S 70°S

60°S60°S

50°S 50°S

40°S40°S

30°S 30°S

20°S20°S

10°S 10°S

0°0°

10°N 10°N

20°N20°N

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

70°N 70°N

80°N80°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

<0.2 0.2..0.3 0.3..0.4 0.4..0.5 0.5..0.6 0.6..0.7 0.7..0.8 0.8..0.9 0.9..0.95 > 0.95

SEAS- Month 2 VEPS


EPS Day 16-45

46-day EPS extension – DJFM – N. extra.

Seas3 EPS

TropicsNorthern Extratropics


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

obs

freq

uenc

y

6113

6504

6773

6329

5506

4652

3633

2895 2133

1616

1888

4841

59767085

7042

6642

52133832

2882 2061

1240

1228

week1 19951215-20061215ECMWF Monthly Forecast, 2MTM upper tercile , Area:Extratropics

BrSc = 0.233 LCBrSkSc= -0.02 Uncertainty= 0.228BrSc = 0.243 LCBrSkSc= -0.06 Uncertainty= 0.228


0

0.2

0.4

0.6

0.8

1

B(S)S_REL= 0.026 ( 0.89)B(S)S_RSL= 0.014 ( 0.06)

sample clim

clim 1990-2001

ex2j ez90

ROC Diagram Reliability Diagram

Seas Month 2


Interannual variability of June rainfall over India

1989-2007

Correlation RMS ERROR

VAREPS- 15 May

Seas - Month 2

Seas – Month 1

0.62

0.40

0.52

0.90

1.15

0.96

Verification: 1ox1o gridded daily rainfall data from IMD


Interannual variability of Atlantic hurricanes

1981-2007

August September October

VAREPS- 15th

Seas - Month 1

Seas – Month 2

0.77

0.31

-0.03

0.37

0.33

0.23

0.69

0.18

0.18

Correlation with HURDAT


Conclusion

• Forecasts for days 12-18 that are generally better than climatology and

persistence of day 5-11. Beyond 20 days the monthly forecast is

marginally skilful.

• The MJO is the main source of predictability in the northern Extratropics

for weeks 3 and 4.

• Extending EPS forecasts can help to produce more frequent and skilful

short-range seasonal forecasts, particularly for some extreme events.


Future Plans

• Run the monthly forecasts twice a week

• Ocean/atmosphere Coupling from day 0

• Extend forecast range to 46-60 days


Multi-model combination

ECMWF NCEP (MRF) ECMWF+NCEP

Extreme tercile probability forecast. Northern Hemisphere. DJF. 84 cases (1990-2002)

T850

Whitaker et al, 2005


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 = 60Forecast start reference is 25-07-20032-meter Temperature anomalyECMWF Monthly Forecasting System

Solid contour at 95% significanceShaded areas above 90% significance

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°N 30°N

40°N40°N

50°N 50°N

60°N60°N

20°W

20°W 0°

0° 20°E

20°E

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 5-11: 29-07-2003/TO/04-08-2003 DAY 12-18 :05-08-2003/TO/11-08-2003

DAY 19-25 :12-08-2003/TO/18-08-2003 DAY 26-32:19-08-2003/TO/25-08-2003

< -6deg -6.. -4 -4.. -2 -2.. -1 -1.. 0 0.. 1 1.. 2 2.. 4 4.. 6 > 6deg

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°N 30°N

40°N40°N

50°N 50°N

60°N60°N

20°W

20°W 0°

0° 20°E

20°E

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°N 30°N

40°N40°N

50°N 50°N

60°N60°N

20°W

20°W 0°

0° 20°E

20°E

DAY 5-11: 27-07-2003/TO/02-08-2003 DAY 12-18 :03-08-2003/TO/09-08-2003

DAY 19-25 :10-08-2003/TO/16-08-2003 DAY 26-32:17-08-2003/TO/23-08-2003

< -6deg -6.. -4 -4.. -2 -2.. -1 -1.. 0 0.. 1 1.. 2 2.. 4 4.. 6 > 6deg

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

20°W

20°W 0°

0° 20°E

20°E

Climatology: 1995-2006Reference date is 30-07-20032-meter temperature anomalyAnalysis WEEK1-4

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°N 30°N

40°N40°N

50°N 50°N

60°N60°N

20°W

20°W 0°

0° 20°E

20°E

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

20°W

20°W 0°

0° 20°E

20°E

WEEK1: 03-08-2003/TO/09-08-2003 WEEK2 :10-08-2003/TO/16-08-2003

WEEK3 :17-08-2003/TO/23-08-2003 WEEK4 :24-08-2003/TO/30-08-2003

< -6deg -6.. -4 -4.. -2 -2.. -1 -1.. 0 0.. 1 1.. 2 2.. 4 4.. 6 > 6deg

MAGICS 6.11 bee10 - nec Fri Apr 27 15:14:30 2007 * 4 ERROR(S) FOUND *

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°N 30°N

40°N40°N

50°N 50°N

60°N60°N

20°W

20°W 0°

0° 20°E

20°E

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°N 30°N

40°N40°N

50°N 50°N

60°N60°N

20°W

20°W 0°

0° 20°E

20°E

DAY 5-11: 29-07-2003/TO/04-08-2003 DAY 12-18 :05-08-2003/TO/11-08-2003

DAY 19-25 :12-08-2003/TO/18-08-2003 DAY 26-32:19-08-2003/TO/25-08-2003

< -6deg -6.. -4 -4.. -2 -2.. -1 -1.. 0 0.. 1 1.. 2 2.. 4 4.. 6 > 6deg

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

20°W

20°W 0°

0° 20°E

20°E

Climatology: 1995-2006Reference date is 30-07-20032-meter temperature anomalyAnalysis WEEK1-4

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°N 30°N

40°N40°N

50°N 50°N

60°N60°N

20°W

20°W 0°

0° 20°E

20°E

30°N 30°N

40°N40°N

50°N 50°N

60°N60°N

20°W

20°W 0°

0° 20°E

20°E

WEEK1: 03-08-2003/TO/09-08-2003 WEEK2 :10-08-2003/TO/16-08-2003

WEEK3 :17-08-2003/TO/23-08-2003 WEEK4 :24-08-2003/TO/30-08-2003

< -6deg -6.. -4 -4.. -2 -2.. -1 -1.. 0 0.. 1 1.. 2 2.. 4 4.. 6 > 6deg

MAGICS 6.11 bee10 - nec Fri Apr 27 15:14:30 2007 * 4 ERROR(S) FOUND *

a) Analysis b) Operational MOFC

c) MOFC CY31R2 d) VAREPS CY31R2

Forecasts started on 23 July 2003 for 2mT anomalies for 3-9 August 2003 (fc day 12-18): impact of model cycle and upgrade to 32-day VAREPS.

Test case : Summer 2003 Heat Wave


The ECMWF VarEPS-monthly forecasting system

• A 51-member ensemble is integrated for 32 days every week

• 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.


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


MJO Propagation

1 2 3 4 5 6 7 8

MJO PHASE

30

28

26

24

22

20

18

16

14

12

10

8

6

4

2

0

DA

YS

MJO (%)

< 5% 5.. 10 10.. 15 15.. 20 20.. 25 25.. 30 30.. 40 40.. 60 60.. 80 > 80%

1 2 3 4 5 6 7 8

MJO PHASE

30

28

26

24

22

20

18

16

14

12

10

8

6

4

2

0

DA

YS

MJO (%)

< 5% 5.. 10 10.. 15 15.. 20 20.. 25 25.. 30 30.. 40 40.. 60 60.. 80 > 80%

ForecastAnalysis


Convection changes to operational massflux scheme (CY32R3)

New formulation of convective entrainment:

Previously linked to moisture convergence

– Now more dependent on the relative dryness of the environment

New formulation of relaxation timescale used in massflux closure:

Previously only varied with horizontal resolution – Now a variable that is dependent on the convective turnover timescale i.e. variable in both space and time also

Impact of these changes is large including a major increase in tropical variability

Bechtold et al, QJRMS, 2008

Monthly Forecasting with Ensembles

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