June 1- 4, 2004 ALADIN Workshop, Innsbruck, Austria

Further case studies using the 3D-Var scheme for the ALADIN/Hungary model

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Further case studies using the Further case studies using the 33DD-Var scheme for the -Var scheme for the ALADIN/HALADIN/Hungaryungary modelmodel

Steluţa Alexandru

András Horányi

June 1- 4, 2004 ALADIN Workshop, Innsbruck, Austria

Further case studies using the 3D-Var scheme for the ALADIN/Hungary model

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3D-Var formulation for ALADIN/HU model3D-Var formulation for ALADIN/HU model

The cost function is sum of:The cost function is sum of:

bJ

bTb xxBxxxJ )()(2

1)( 1

oJ

oTo yHxRyHx )()(2

1 1

background termbackground term

observation termobservation term

Background error covariance matrix:

NMC method

Background Background

information:information: 6h forecast6h forecast

Observations available:

SYNOP + TEMP

June 1- 4, 2004 ALADIN Workshop, Innsbruck, Austria

Further case studies using the 3D-Var scheme for the ALADIN/Hungary model

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Case studiesCase studies

The “inversion” case (December 27, 2002)

The “snow” case (January 7, 2003)

June 1- 4, 2004 ALADIN Workshop, Innsbruck, Austria

Further case studies using the 3D-Var scheme for the ALADIN/Hungary model

4

12h forecast24h forecast

The “inversion” case (December 27, 2002)The “inversion” case (December 27, 2002)

3dvar

oper

observations

No big differences between the two models.No big differences between the two models.

26.12 12 UTC run

27.12 00 UTC run

June 1- 4, 2004 ALADIN Workshop, Innsbruck, Austria

Further case studies using the 3D-Var scheme for the ALADIN/Hungary model

5

The “inversion” case (December 27, 2002)The “inversion” case (December 27, 2002)

height

(km)

oper

44

00

-6-6

3dvar

-4-4

22

00

The operational analysis showed a strong inversion, closer to reality.

The operational analysis showed a strong inversion, closer to reality.

analysis

27.12 12 UTC run

June 1- 4, 2004 ALADIN Workshop, Innsbruck, Austria

Further case studies using the 3D-Var scheme for the ALADIN/Hungary model

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The “inversion” case (December 27, 2002)The “inversion” case (December 27, 2002)

3dvar

operobservations

observations

LBC

first guess

3dvar analysisanalysis

• The first guess was too far from observations.

• Accurate information from the LBC.

• The first guess was too far from observations.

• Accurate information from the LBC.

analysis

27.12 12 UTC run

June 1- 4, 2004 ALADIN Workshop, Innsbruck, Austria

Further case studies using the 3D-Var scheme for the ALADIN/Hungary model

7

height

(km)

-4-4

00

3dvar TLS

22

The “inversion” case (December 27, 2002)The “inversion” case (December 27, 2002)

44

00

-6-6

3dvar FG=ARP

ARPEGE first guess was closer to reality.ARPEGE first guess was closer to reality.

27.12 12 UTC run

analysis

June 1- 4, 2004 ALADIN Workshop, Innsbruck, Austria

Further case studies using the 3D-Var scheme for the ALADIN/Hungary model

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11 9

1614

9

914

13mm/12hmm/12h

806UTC-18UTC06UTC-18UTC

The “snow” case The “snow” case (January 7, 2003)(January 7, 2003)

1212

2424

oper

3dvar3dvar

1111

2323

Both models predicted the snowfall over Hungary.

Both models predicted the snowfall over Hungary.

June 1- 4, 2004 ALADIN Workshop, Innsbruck, Austria

Further case studies using the 3D-Var scheme for the ALADIN/Hungary model

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The “snow” case The “snow” case (January 7, 2003)(January 7, 2003)

850 hPa

3dvar3dvar

129129

oper

128128Both models predicted the low-pressure

system.Both models predicted the low-pressure

system.

24h forecast

June 1- 4, 2004 ALADIN Workshop, Innsbruck, Austria

Further case studies using the 3D-Var scheme for the ALADIN/Hungary model

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The “snow” case The “snow” case (January 7, 2003)(January 7, 2003)

-2.5 hPa/s

-2.8 hPa/s

3dvar3dvar 700 hPa700 hPa

oper24h forecast

Similar forecasts for other fields too.Similar forecasts for other fields too.

June 1- 4, 2004 ALADIN Workshop, Innsbruck, Austria

Further case studies using the 3D-Var scheme for the ALADIN/Hungary model

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ConclusionsConclusions

• The The 3D-Var procedure works properly. 3D-Var procedure works properly.

• But with some limitations.But with some limitations.

• It is important to have accurate lateral It is important to have accurate lateral boundary conditions.boundary conditions.

• The improvements introduced in the The improvements introduced in the analysis were lost after 6h.analysis were lost after 6h.

June 1- 4, 2004 ALADIN Workshop, Innsbruck, Austria

Further case studies using the 3D-Var scheme for the ALADIN/Hungary model

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THANK YOU FOR YOUR THANK YOU FOR YOUR ATTENTION!ATTENTION!