Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME Improvement of the...

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

Improvement of the Eddy-Improvement of the Eddy-Diffusivity Mass Flux scheme Diffusivity Mass Flux scheme

using Kain-Fritsch approach for using Kain-Fritsch approach for Meso-NH and AROMEMeso-NH and AROME

CNRM/GMME/TURBAU

Julien PERGAUD, Sylvie MALARDEL,Valery MASSON

July 2006, 3rd

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

Introduction : EDMF scheme and purpose of our work

1/ Description of improved EDMF scheme– Equations for the Updraft Model– Definition of Lateral Mass Exchanges

– Closure Assumptions

2/ First Results for different study cases – Eurocs/ARM– Bomex

Conclusion : Work in progress and questions

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

Introduction

• Updraft starting from the ground– Dry BL – Dry BL and

shallow Cu– Sc BL (not

tested yet)

• Use of conservatives variables

EDMF Scheme

• EDMF scheme Soares et al,2004

TurbulenceConvection schemeSoares et al,2004

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

IntroductionEDMF Scheme :Results Eurocs/Arm (Malardel,Auguste)

'θw'EDMF L

'rw'EDMF tEDMF Rc

LES Rc

'θw'LES L

LES Rc

'θw'LES L

'rw'LES t

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

IntroductionEDMF Scheme : Results Bomex (Malardel,Auguste)

EDMF Rc'θw'EDMF L

'rw'EDMF t

LES RcLES Rc

'rw'EDMF t

'θw'LES L 'rw'LES t

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

IntroductionEDMF Scheme : improvement

Soares et al,2004

Continuity of mass flux

defintion

Better definition of entrainmentdetrainment

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

• Eq for w

• Eq for conservative

variables

Description of EDMF improved scheme

DEz

M

u

u

DφφEz

Mφ

w²M

EbaB

z

ww

1/ Equations for the updraft model

EDMF

KFB

w and MF equationsthe fractionnal updraft area

• Eq for the Mass flux

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

• Entrainment and detrainment in clouds are defined as in the KF formulation (Kain & Fritsch,1990):

2/ Definition of Lateral Mass Exchanges

Updraft-Cloud Zone

Limit between Updraft and environmentD

EE

ENVIRONMENT

Description of EDMF improved scheme

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

• Entrainment and detrainment in clouds are defined as in the KF formulation (Kain & Fritsch,1990):

2/ Definition of Lateral Mass Exchanges

Limit between Updraft and environment

Updraft-Cloud ZoneMaximum

updraft part detrainable to environment

ENVIRONMENT

Description of EDMF improved scheme

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

• Entrainment and detrainment in clouds are defined as in the KF formulation (Kain & Fritsch,1990):

2/ Definition of Lateral Mass Exchanges

Updraft-cloud Zone

Maximum environmental

part entrainable to the updraft

Limit between Updraft and environment

ENVIRONMENT

Description of EDMF improved scheme

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

• Entrainment and detrainment in clouds are defined as in the KF formulation (Kain & Fritsch,1990):

2/ Definition of Lateral Mass Exchanges

Updraft-cloud Zone

Updraft-environmental Mixture Zone

Limit between Updraft and environment

ENVIRONMENT

Description of EDMF improved scheme

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

• Entrainment and detrainment in clouds are defined as in the KF formulation (Kain & Fritsch,1990):

2/ Definition of Lateral Mass Exchanges

ENVIRONMENT

Updraft-environmental Mixture Zone

Mu

Updraft-Cloud Zone

BuoyantAir

HeavyAir

BuoyantAir

HeavyAir

Mt

Description of EDMF improved scheme

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

• Entrainment and detrainment in clouds are defined as in the KF formulation (Kain & Fritsch,1990):

2/ Definition of Lateral Mass Exchanges

ENVIRONMENT

Updraft-environmental Mixture Zone

EE

MuBuoyant

Air

HeavyAir

Updraft-Cloud Zone

BuoyantAir

HeavyAirD

E

Description of EDMF improved scheme

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

• KF formalism : E and D depends on v between environment and updraft

where with

- f(x) is a gaussian type distribution with f(0)=f(1)=0,

- c is the critical mixed fraction and the environmental mass fraction linked to the buoyancy

- Ro is the cloud Radius

2/ Definition of Lateral Mass Exchanges

χc

χf(χ)dχΔMtE0

1

1χc

χ)f(χ)dχ(ΔMtD

0/ RcMM etrut 2.0etrc

Description of EDMF improved scheme

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

2/ Definition of Lateral Mass Exchanges

dnL

MCE

E )1(

upL

MCD

D )1(

• From the ground to the Condensation Level, entrainment and detrainment are defined as in Lappen & Randall ,2001:

Lup and Ldn are the downward and upward BL89 mixing lengths

is the fractionnal updraft area.

In Lappen & Randall (2001) CE =1.0 and CD =1.5

This formulation needs diagnosed

Link with the turbulence

Description of EDMF improved scheme

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

3/ Closure assumptions

e

w'θ'θθ

sLLu

e

w'r'rr

sttu

• Initialisation of the parcel characteristics using Soares et al (2004)

with =0.3

• Moreover the mass flux at the ground is defined as :

sMss eCM3

2

where CMs corresponds to a fractionnal updraft area

defined for each study case

Description of EDMF improved scheme

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

First Results for different study cases1/ Eurocs/ARM

Evolution of Mean rc (kg/kg)

LES 1 D

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

First Results for different study cases1/ Eurocs/ARM

Profile of Mass flux, Entrainment and Detrainment averaged between 8 and 9 hours

Mass Flux Entrainment Detrainment

LCLLCL

LCL

sMss eCM3

2 09.0MsC

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

First Results for different study cases1/ Eurocs/ARM

1D Results

Average between8 and 9 hours

Evolutionof flux over 15 hours

LES Results

Average between8 and 9 hours

Evolutionof flux over 15 hours

'θw' L 'θw' L

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

First Results for different study cases1/ Eurocs/ARM

LES Results

Average between8 and 9 hours

Evolutionof flux over 15 hours

'rw' t

1D Results

Average between8 and 9 hours

Evolutionof flux over 15 hours

'rw' t

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

First Results for different study cases2/ BOMEX

LES 1 D

Evolution of Mean rc (kg/kg)

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

First Results for different study cases2/ BOMEX

Profile of Mass flux, Entrainment and Detrainment averaged between 8 and 9 hours

Mass Flux Entrainment Detrainment

LCL LCLLCL

sMss eCM3

2 05.0MsC

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

First Results for different study cases2/ BOMEX

'θw' L

'rw' t

LES Results

Average between5 and 6 hours

1D Results

Average between5 and 6 hours'rw' t

'θw' L

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

Conclusion : Work in progress and questions

The next stages in our work will be to

• Improve the closure asumption : surface mass flux

•Assess the sensibility of the scheme to different parameters : a and b in the w equation, CE and CD, and Ro

• Test the scheme with others cases : dry Bl or Sc Bl

• Implement the scheme in AROME and test in 3D runs

,...),,'',( CINCAPEwefM vs

Improvement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROMEImprovement of the EDMF Scheme using Kain Fristch approach for Meso-NH and AROME

Conclusion : Work in progress and questions

Some questions are interesting

• Must we use a prognostic approach to have a better view of the convection?

for example

• Links with deep convection, 3D runs ?

w²M

EbaB

z

ww

t

w