Testing bulk parameterization of microphysics in ALARO 10

Tomislav Kovacic

DHMZ, Croatia

ALARO 10

• ALADIN dynamics + MNH physics

• Hydrostatic version of AROME + parameterization of convection

• Prototype

• Leader: Gwenaelle Hello

Gard case

• • Date: 2002-09-08

• start time 2002-09-09 12

• validity time=2002-09-09 00

• Domain: A specific domain for this case 192x192 (smaller than aladin oper)

GARD 2002-09-08 TSTEP=30 s

GARD 2002-09-08 TSTEP=120 s

GARD 2002-09-08 TSTEP=360 s

Time splitting for microphysical scheme

• Time step used in operational version of the model is to long for microphysics and the consequence is to few precipitation.

• Time splitting for microphysical scheme has to be introduced in the model.

• Iterations of microphysics:– microphysical scheme is performed several

times in one time step of the model

Method

• Maximal amount of precipitation on the ground

• Time steps: 30, 60, 120, 180, 240, 300, 360 and 400 s

• Iterations: 1,2,3,6 and 9

GARD 2002-09-08 TIME=12 h

Area 1

0,005,00

10,0015,0020,0025,0030,0035,0040,00

0 100 200 300 400 500

TSTEP

Acc

um

ula

ted p

reci

pitat

ion

GARD 2002-09-08 TIME=12 h

Area 1

0,005,0010,0015,0020,0025,0030,0035,0040,00

0,00 100,00 200,00 300,00 400,00 500,00

MPTSTEP

Acc

um

ula

ted p

reci

pitat

ion

GARD 2002-09-08 TIME=12 h

GARD 2002-09-08 TIME=12 h

Area 1

30

35

40

45

50

0 100 200 300 400

TSTEP

Acc

um

ula

ted c

onve

ctiv

e

pre

cipitat

ion

GARD 2002-09-08 TIME=12 h

Area 1

30

3540

45

50

0 100 200 300 400 500

MPTSTEP

Acc

um

ula

ted

conve

ctiv

e

pre

cipitat

ion

GARD 2002-09-08 TIME=12 h

Area 3

0,00

10,0020,00

30,00

40,0050,00

60,00

70,0080,00

90,00

0 100 200 300 400 500

TSTEP

Acc

um

ula

ted p

reci

pitai

on

GARD 2002-09-08 TIME=12 h

Area 3

0,00

10,0020,00

30,0040,00

50,0060,00

70,0080,00

90,00

0,00 100,00 200,00 300,00 400,00 500,00

MPTSTEP

Acc

um

ula

ted p

reci

pitai

on

GARD 2002-09-08 TIME=12 h

Area 3

5

7

9

11

13

15

0 100 200 300 400 500

TSTEP

Acc

um

ula

ted c

onve

ctiv

e

pre

cipitat

ion

GARD 2002-09-08 TIME=12 h

Area 3

5

7

9

11

13

15

0 100 200 300 400 500

MPTSTEP

Acc

um

ula

ted c

onve

ctiv

e

pre

cipitat

ion

An other consequence

• Geographical position of the precipitation area is changing

• It moves upstream

GARD 9-8-2002TSTEP=120 s ITERATIONS=1

GARD 9-8-2002TSTEP=120 s ITERATIONS=3

GARD 9-8-2002TSTEP=120 s ITERATIONS=3

Conclusions

• The amount of precipitation increases with decreasing time step

• It is converging for all studied cases

• Time splitting doesn’t converge always and when it does it is not the same value as for the same time step of the model

• Shorter time step must be used