1 Status of AROME Physics Sylvie Malardel Yann Seity, Gwenaëlle Hello, Christine Lac, Valery...
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Transcript of 1 Status of AROME Physics Sylvie Malardel Yann Seity, Gwenaëlle Hello, Christine Lac, Valery...
1
Status of AROME Physics
Sylvie MalardelYann Seity, Gwenaëlle Hello, Christine
Lac, Valery Masson, Patrick Lemoigne et al
Météo-France/CNRM et Laboratoire d’aérologie
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AROMEAROME
Aladin dynamical core
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AROME Physics
Current ECMWF radiation scheme called every 15 min (F.M. for SW and RRTM for LW)
Microphysics (vapor+5 hydrometeors) Turbulence (CBR, pronostic TKE) Shallow convection (KFB) + a subgrid representation of clouds
Externalised surface Isba Simple schemes for sea and lakes TEB
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The Daily Arome prototype
MIDPYR since june 2005,
SUDE since september 2005
Replaced by NORE this winter
(plots on ALADIN2 WebSite)
This Arome is running
every day on different domains
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MIDPYRSUDE
NORE
PARI
BRET
AROME domains over FRANCE
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Deep Clouds
•Microphysics
•Coupling with the dynamics
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An AROME good forecast : 21 June 2005
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12 TU
Inst. AROME rainfalls L41 AROME wind
15 TU18 TU21 TU24 TU
21 June 2005 Case
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AROME coupled with Aladin oper
AROME coupled with Aladin 3DVAR
15 TU
21 June 2005 Case
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Z > 60 dBz
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km
100 km Tabary, 2002
(x) hail + graupel
(o) hail
( ) rain
(o) hail
(x) hail + graupel
( ) rain
graupel
Simulation (Meso-NH)
Microphysical retrievals : IOP 2A (intense convection)
Deep clouds
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hail + graupel
dry snow
rain
Pujol et al., 2005
18:10 UT
18:30 UT
snow
rain
hail + graupel
Meso-NH simulation
Microphysical retrievals : IOP 3 (moderate convection)
Deep clouds
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max : 135 mm
max : 25 mm
m mm
Quasi-stationnary MCS 13-14 Oct. 1995
Cumulated precipitation 01 UTC to 06 UTC the 14th Oct. 1995
MESO-NH, x=10km
max: 31 mm
MESO-NH, x=2.5kmOBSERVATIONS
(Ducrocq et al, 2002)
Initial conditions: ARPEGE analysis at 18UTC
mMESO-NH, x=2.5km
Initialisation Ducrocq et al
(2000)’s
max : 99 mm
Deep clouds
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Deep clouds
As Méso-NH, Arome is able to simulate correctly the organisation of mesoscale convective organisation
Sensitivity to coupling and initial condition
For AROME in 2006
Use diagnostics to evaluate more objectively and statisticaly precipitating events
Adaptation of numerical aspects of the sedimentation parametrization (time splitting) to longer time steps (> 60s)
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Fog (and low clouds)
•Microphysics
•Radiation
•Vertical resolution
•Turbulence in stable layers
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First case of Fog : 7 January 2005
09 TUAROME 2 last levels cloud cover
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15 TU
First case of Fog : 7 January 2005
AROME 2 last levels cloud cover
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Fog
Scientist Model Levels
<50m
Levels
<200m
E.Terradellas Hirlam-INM
(1D version used in Spain)
1 3
O. Liechti tBM 2 7
N.W. Nielsen Hirlam-DMI 13 20
T. Bergot Cobel-Isba 13 20
M. Mueller Cobel-Noah 18 30
J.Cuxart/A.Mira MesoNH 50 89
Bergot et al., 2005, submitted :Intercomparison of 1D numerical models for prediction of the fog( , turbulence, z)
2 events at Paris-CdG. 4 sets of initial conditions (RS): 18UTC (onset), 21 (thickening), 00 (mature) and 03 (disspation)
just a few studies with Meso-NH … But A PRIORITY for AROME
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Meso-NH with sedimentation
Cumulated liquid water content
Meso-NH without sedimentation of small droplets
Bergot et al., 2005, submitted
Late dissipation due to excessive rc : lack of gravitational settling
Crude test : Modification of the autoconversion threshold
Fog
Initialization at 03UTC
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Microphysics : Implementation of the sedimentation for small droplets
Tests on the sensitivity to vertical resolution Additional levels to L41 ? (Cobel-Isba with L41 shows degradation)
Evaluation on CAPITOUL and on several international airports. Run of AROME on Ile-de-France on winter 2005 and in 1D on Casablanca and Varsovie (to be confirmed)
For AROME in 2006
Fog
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Convective boundary layersand stratocumulus
•Shallow convection
•Turbulence
•Subgrid clouds
•Microphysics
•Surface
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Meso-NH with SUBGRID COND + SHALLOW : Adjustment time of 3h in the closure
2005/08/20
09 TU
AROME
Meso-NH with SUBGRID COND + SHALLOW 30min : Adjustment time of 30min
Coupling with Aladin oper (r0)
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Bomex :
LES
'' lw
h3
h1*w
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ARM :
LES
'' lw
h3
h1*w
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ARM : cloud mixing ratio
LES h3
h1 *w
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For AROME in 2006
BL clouds : Cu
1. Modification of the KFB closure (w*, Grant et al, 1999)
2. Improvement of subgrid cloud representation (Bechtold et al, 1995, Lenderink and Siebesma, 2000)
3. Test of EDMF scheme in Meso-NH (P.Soares)
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x= y= 2.5kmSCM
Cloud water mixing ratio
0h LT 12hLT 0hLT
LES
0h LT 12hLT 0hLT
x= y= 500m
Stratocumulus : What’s about the resolutions of AROME ?
I.Sandu
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Liquid Water Path
LES
x=500m,z=10m
x=500m,z=25m
x=500m,z=50m
x=500m,z=80m
I. Sandu
BL clouds : Sc
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For Arome , second part of 2006
Sensitivity tests on vertical resolution for cloud-top entrainmentAdditional levels to L41?
Interest of an entrainment parametrization (Lock, 2001, 2004. ARPEGE-Climat).
Preliminary tests in Meso-NH at the resolutions of AROME
BL clouds : Sc
Diurnal cycle of Sc is maintained at the resolution of Arome
LWC more sensitive to lower z than lower x
Main impact of z at the top of Sc (entrainment) than beneath
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Evaluation CARBOEUROPE
Boundary Layer HeightMESONH vs RS La Cape Sud
0
500
1000
1500
2000
2500
0 500 1000 1500 2000 2500
observed
sim
ula
ted
25-may
26-may
27-may
31-may
06-june
07-june
08-juin
09-juin
10-juin
MESO-NH vs PIPER
La Cape Sud : Comparison Meso-NH/RS of BL height (parcel method) between 6 and 17UTC
Weak overestimation during the afternoon
Weak underestimation during the morning
Forecasts of Meso-NH (8km) in an operational mode during the experiment
Dry CBL
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1. The K-diffusion doesn’t take into account countergradient.
2. Entrainment is not treated explicitly in the K-diffusion approach.
3. But diffusion remains necessary, for transition to neutral or stable BL.
Too unstable
Too sharpe inversion due to lack of top-entrainment33
2Kwith ''
eLCz
Kwp
Eddy-diffusivity (local) :
Dry CBL BUT limitations are well-known, inherent to Eddy-diffusivity
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On L
1L
2L
On the TOMs
2L without TOMs
2L with TOMs
Dry CBL 1. Countergradient with Third order moments
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Dry CBL For AROME in 2006
1. TOMs on heat momentum fitted on LES already implemented in Meso-NH evaluation of the impact for AROME on CBL (needs of evaluation on test cases, impact on unreal rolls ?)
2. EDMF scheme : evaluation of the impact in Meso-NH during the 1st sem.2006 (In collaboration with P.Soares)
3. Comparison EDMF/TOMS on the same casesUnder development in Meso-NH (2006-
2008)
1. Improvement of EDMF scheme : entrainment, extension to momentum transport (In collaboration with P.Soares in 2006)
2. Parametrization of TOMs with an entraining plume used to find the mass-flux.
3. Improvement of the BL89 mixing length in the same way (V.Masson)
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Summary• An Arome daily prototype has been running for 6
months (without any blow up)• Some good forcasts and some less good (but only
qualitative and episodic validation) • Some imperative improvement have to be done
quickly on the physics before more serious validation– Shallow convection and subgrid clouds– Fog dissipation
• Numerical improvement : SL sedimentation• Other preoccupations : Sc, Dry BL etc