“Nature Run” Diagnostics Thomas Jung ECMWF. Another “Nature Run” A large set of seasonal T L 511L91 integrations has been carried out for many summers.

“Nature Run” Diagnostics

Thomas Jung

ECMWF

Another “Nature Run”

• A large set of seasonal TL511L91 integrations has been carried out for many summers and winters:– NDJFM 1990-2005– JJASON 1990-2005

• Data have been archived on PL and SFC levels only (6-hourly)

• Advantage: We get an idea of the climate of IFS cycle 31R1 at TL511 used to carry out the “Nature Run”

Extratropical Cyclones

Vorticity Histograms: Extratropical Cyclone Tracks

Histogram: Intensity

0 5 10 15 20Vorticity (10 5̂ s -̂1)

0

500

1000

1500

2000

2500

3000

Nu

mb

er

of C

ase

s

EC-T511

ERA-40

Maximum Vorticity Histograms:Extratropical Cyclone Tracks

EC-T511

ERA-40

Histogram: Maximum Intensity

0 5 10 15 20Maximum Vorticity (10 6̂ s -̂1)

0

50

100

150

200

Nu

mb

er

of C

ase

s

Number of Extratropical Cyclones

Number of VO Maxima (er40 DJFM 1990-2005)

-2

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Number of VO Maxima (etn8-er40 DJFM 1990-2005)

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0.5

1

1.5

2

2.5

3

3.5

Number of VO Maxima (eut3-er40 DJFM 1990-2005)

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0.5

1

1.5

2

2.5

3

3.5

Number of VO Maxima (eut3-etn8 DJFM 1990-2005)

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0.5

1

1.5

2

2.5

3

3.5

Number of VO Maxima (er40 DJFM 1990-2005)

-2

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Number of VO Maxima (etn8-er40 DJFM 1990-2005)

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0.5

1

1.5

2

2.5

3

3.5

Number of VO Maxima (eut3-er40 DJFM 1990-2005)

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0.5

1

1.5

2

2.5

3

3.5

Number of VO Maxima (eut3-etn8 DJFM 1990-2005)

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0.5

1

1.5

2

2.5

3

3.5

Life time: 2 days or longer; Minimum migration: 1000km

ERA40 EC-T511 - ERA40

Mean Intensity of VO Maxima (er40 DJFM 1990-2005)

-1.2

1.2

1.8

2.4

3

3.6

4.2

4.8

5.4

6

6.6

7.2

7.8

8.4

9

Mean Intensity of VO Maxima (etn8-er40 DJFM 1990-2005)

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0.2

0.4

0.6

0.8

1

1.2

1.4

Mean Intensity of VO Maxima (eut3-er40 DJFM 1990-2005)

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0.2

0.4

0.6

0.8

1

1.2

1.4

Mean Intensity of VO Maxima (eut3-etn8 DJFM 1990-2005)

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0.2

0.4

0.6

0.8

1

1.2

1.4

Mean Extratropical Cyclone Intensity

Life time: 2 days or longer; Minimum migration: 1000km

ERA40 EC-T511 - ERA40

Mean Intensity of VO Maxima (er40 DJFM 1990-2005)

-1.2

1.2

1.8

2.4

3

3.6

4.2

4.8

5.4

6

6.6

7.2

7.8

8.4

9

Mean Intensity of VO Maxima (etn8-er40 DJFM 1990-2005)

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0.2

0.4

0.6

0.8

1

1.2

1.4

Mean Intensity of VO Maxima (eut3-er40 DJFM 1990-2005)

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0.2

0.4

0.6

0.8

1

1.2

1.4

Mean Intensity of VO Maxima (eut3-etn8 DJFM 1990-2005)

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0.2

0.4

0.6

0.8

1

1.2

1.4

Mean Growth-Rate

Life time: 2 days or longer; Minimum migration: 1000km

ERA40 EC-T511 - ERA40Mean Growth-Rate of VO Maxima (er40 DJFM 1990-2005)

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Mean Grow th-Rate of VO Maxim a (etn8-er40 DJFM 1990-2005)

-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Mean Grow th-Rate of VO Maxim a (eut3-er40 DJFM 1990-2005)

-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Mean Grow th-Rate of VO Maxim a (eut3-etn8 DJFM 1990-2005)

-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Mean Growth-Rate of VO Maxima (er40 DJFM 1990-2005)

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Mean Grow th-Rate of VO Maxim a (etn8-er40 DJFM 1990-2005)

-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Mean Grow th-Rate of VO Maxim a (eut3-er40 DJFM 1990-2005)

-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Mean Grow th-Rate of VO Maxim a (eut3-etn8 DJFM 1990-2005)

-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Summary: Extratropical Cyclones 31R1 @ T511 (DJFM)

• Synoptic activity (extratropics):– Generally well represented– Distribution of storm frequency quite realistic– Problems in the Gulf Stream/Kurushio area?– Too many systems in the eastern Atlantic

(blocking)

Tropical Cyclones & African Summer Monsoon in T511 Run

Tropical Cyclone Tracks (Atlantic)

10°N10°N

20°N 20°N

30°N30°N

40°N 40°N

100°W

100°W 80°W

80°W 60°W

60°W 40°W

40°W 20°W

20°W 0°

0°

10°N10°N

20°N 20°N

30°N30°N

40°N 40°N

100°W

100°W 80°W

80°W 60°W

60°W 40°W

40°W 20°W

20°W 0°

0°

10°N10°N

20°N 20°N

30°N30°N

40°N 40°N

100°W

100°W 80°W

80°W 60°W

60°W 40°W

40°W 20°W

20°W 0°

0°

10°N10°N

20°N 20°N

30°N30°N

40°N 40°N

100°W

100°W 80°W

80°W 60°W

60°W 40°W

40°W 20°W

20°W 0°

0°

10°N10°N

20°N 20°N

30°N30°N

40°N 40°N

100°W

100°W 80°W

80°W 60°W

60°W 40°W

40°W 20°W

20°W 0°

0°

10°N10°N

20°N 20°N

30°N30°N

40°N 40°N

100°W

100°W 80°W

80°W 60°W

60°W 40°W

40°W 20°W

20°W 0°

0°

10°N10°N

20°N 20°N

30°N30°N

40°N 40°N

100°W

100°W 80°W

80°W 60°W

60°W 40°W

40°W 20°W

20°W 0°

0°

10°N10°N

20°N 20°N

30°N30°N

40°N 40°N

100°W

100°W 80°W

80°W 60°W

60°W 40°W

40°W 20°W

20°W 0°

0°

2005 2006

TL511

TL255

TL159

TL95

TS Cat 1 Cat 2 Cat 3 Cat 4 Cat 5Tropical storm intensity

0

1

2

3

4

5

6

7

8

9

10

Nu

mb

er

of t

rop

ica

l sto

rms

Atlantic tropical storm intensity1990-2006

T95T159T255T511T159 CY30R2OBS

TS Cat 1 Cat 2 Cat 3 Cat 4 Cat 5Intensity

0

1

2

3

4

5

6

7

8

Nu

mb

er

of T

rop

ica

l Sto

rms

Eastern North Pacific tropical storm intensity1990-2006

T63T159T255T511T159 CY30R2Obs

Resolution and Intensity of Tropical Storms

Synoptic Activity: Vrot @ 700hPa (JJAS)

(a) STD Lowpass Vrot er40 (700hPa 6-9 1990-2006)

0.25

1

3

5

7

9

(b) STD Highpass Vrot er40 (700hPa 6-9 1990-2006)

0.25

1

3

5

7

9

(c) Diff STD Lowpass Vrot etup-er40 (700hPa 6-9 1990-2006)

-2.1

-1.5

-0.9

-0.3

0.3

0.9

1.5

2.1

(d) Diff STD Highpass Vrot etup-er40 (700hPa 6-9 1990-2006)

-2.1

-1.5

-0.9

-0.3

0.3

0.9

1.5

2.1

TL511-ERA40

(a) STD Lowpass Vrot er40 (700hPa 6-9 1990-2006)

0.25

1

3

5

7

9

(b) STD Highpass Vrot er40 (700hPa 6-9 1990-2006)

0.25

1

3

5

7

9

(c) Diff STD Lowpass Vrot etie-er40 (700hPa 6-9 1990-2006)

-2.1

-1.5

-0.9

-0.3

0.3

0.9

1.5

2.1

(d) Diff STD Highpass Vrot etie-er40 (700hPa 6-9 1990-2006)

-2.1

-1.5

-0.9

-0.3

0.3

0.9

1.5

2.1

ERA40

Zonal Mean Zonal Wind: AEJ Area

0O 10ON 20ON 30ON 40ON

1000

800

600

400

200

(a) Average Zonal Mean Zonal Wind (ERA40)

-17.5

-15

-12.5

-10

-7.5

-5

-2.5

2.5

5

7.5

10

12.5

15

17.5

0O 10ON 20ON 30ON 40ON

1000

800

600

400

200

(b) Average Zonal Mean Zonal Wind (T255)

-17.5

-15

-12.5

-10

-7.5

-5

-2.5

2.5

5

7.5

10

12.5

15

17.5

0O 10ON 20ON 30ON 40ON

1000

800

600

400

200

(c) Average Zonal Mean Zonal Wind (T511)

-17.5

-15

-12.5

-10

-7.5

-5

-2.5

2.5

5

7.5

10

12.5

15

17.5

0O 10ON 20ON 30ON 40ON

1000

800

600

400

200

(d) Difference (T255-ERA40)

-7

-6

-5

-4

-3

-2

-1

1

2

3

4

5

6

7

0O 10ON 20ON 30ON 40ON

1000

800

600

400

200

(e) Difference (T511-ERA40)

-7

-6

-5

-4

-3

-2

-1

1

2

3

4

5

6

7

0O 10ON 20ON 30ON 40ON

1000

800

600

400

200

(f) Difference (T511-T255)

-7

-6

-5

-4

-3

-2

-1

1

2

3

4

5

6

7

200 hPa Velocity Potential

-12

-12-6

-6

-6

0

0

0 6

6

6

Velocity Potential 200hPa er40 (6-9 1990-2005)

-3

0

0

0

0

3

3

Velocity Potential 200hPa etup-er40 (6-9 1990-2005)

ERA40

T511 - ERA40

Summary: Tropical Cyclones 31R1 @ T511 (DJFM)

• T511 model produces quite realistic frequency of occurrence of TS/Hurricanes in the Atlantic.

• North African Monsoon too strong + northward shifted.

• AEJ is too weak (problem at higher resolution).• Perhaps slightly too much AEW activity.• Strong problems in the western tropical Pacific

(too little atmospheric upwelling). Problem larger at higher resolution.

Some Other Issues: Model Climate 31R1 @ T511

• Amplitude of the MJO is underestimated (better in recent cycles but still an issue).

• Convectively coupled Kelvin waves in the tropics are underestimated (better from 32R3 onwards).

• Too little (much) precipitation over the tropical continents (oceans) (improved in recent cycles).

• No QBO• Euro-Atlantic blocking significantly

underestimated (large improvements in 33R1).• Anti-cyclonic circulation bias in the North Pacific

(fixed in 32R3)

Tropical Cyclones: 32R3 vs 32R2

Tropical Waves: OLRA (JJA)Power: Symmetric Tropical OLRA (noaa)

-20 -10 0 10 20Westward Modes Wavenumber Eastward Modes

0.0

0.1

0.2

0.3

0.4

0.5

Fre

quen

cy (C

PD

)

Power: Symmetric Tropical OLRA (ewdd)

-20 -10 0 10 20Westward Modes Wavenumber Eastward Modes

0.0

0.1

0.2

0.3

0.4

0.5

Fre

quen

cy (C

PD

)

Power: Symmetric Tropical OLRA (ewdf)

-20 -10 0 10 20Westward Modes Wavenumber Eastward Modes

0.0

0.1

0.2

0.3

0.4

0.5

Fre

quen

cy (C

PD

)

OBS

32R2 32R3

Tropical Cyclones Frequencies (Annual Mean)

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

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 180°

180° 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

6.6 6.9 12.88.4 3.1 15.719.6 32.3 28.26.2 12.2 5.2

16.5 9.2 13 10.8 11 8.8 4.7 7.1 5.8

Ensemble size = 1Forecast start reference is 01/11/YYYYTropical Storm FrequencyECMWF Seasonal Forecast

Annual Mean

CY32R2 CY32R3 OBS

Note: TL159L91

Tropical Cyclones Frequencies (Annual Mean)

Tropical storm frequency

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

< 1 1.. 2 2.. 3 3.. 4 4.. 5 5.. 6 6.. 7 7.. 8 8.. 9 > 9

Tropical storm frequency

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

< 1 1.. 2 2.. 3 3.. 4 4.. 5 5.. 6 6.. 7 7.. 8 8.. 9 > 9

Tropical storm frequency

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

<-2 -2..-1.5 -1.5..-1 -1..-0.5 -0.5..0.5 0.5..1 1..1.5 1.5..2 > 2

32R1 32R3

32R3-32R1

Tropical Cyclones in Recent Model Cycles

• Generally there is an increase in the number/intensity of tropical cyclones/hurricanes.

• Particularly lower resolution versions perform better than older cycles (e.g., US landfall).

• Large increases in the western tropical Pacific (partly due changes in the large-scale atmospheric circulation). Too large?

Tropical Cyclone Forecasts:

T799 vs T511

948

T511 L60 20050828 00UTC ECMWF FC t+36 VT: 20050829 12UTC Surf: MSL

942

T799 L91 20050828 00UTC ECMWF FC t+36 VT: 20050829 12UTC Surf: MSL

963

T511 L60 20050826 12UTC ECMWF FC t+72 VT: 20050829 12UTC Surf: MSL

944

T799 L91 20050826 12UTC ECMWF FC t+72 VT: 20050829 12UTC Surf: MSL

Forecasts of Katrina for Monday 29 Aug. 12 UTC

T511 T799

t+36 t+36

t+72 t+72

Observed SLP: 922 hPa

969

T511 L60 20050922 12UTC ECMWF FC t+36 VT: 20050924 00UTC Surf: MSL

971

T799 L91 20050922 12UTC ECMWF FC t+36 VT: 20050924 00UTC Surf: MSL

983

T511 L60 20050921 00UTC ECMWF FC t+72 VT: 20050924 00UTC Surf: MSL

976

T799 L91 20050921 00UTC ECMWF FC t+72 VT: 20050924 00UTC Surf: MSL

Forecasts of Rita for Saturday 24 Sep. 12 UTC

T511 T799

t+36 t+36

t+72t+72Observed SLP: 930 hPa

Sensitivity to Horizontal Resolution

• Short-range and medium-range forecasts suggest that T799, if anything, produces stronger hurricanes than T511.

• Resolution studies, however, suggests, that some aspects of the tropical climate (i.e., beyond the medium-range) of 31R1 deteriorate when increasing horizontal resolution (T159->T511). So it may be possible that T799 performs worse than T511.

• In the extratropics the largest changes occur when going from T95 to T159. Rather little changes occur beyond T159 (T159->T511). Hence, it seems reasonable to assume that T511 and T799 perform similar.