Status of AROME Physics
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Transcript Status of AROME Physics
Status of AROME Physics
Sylvie Malardel
Yann Seity, Gwenaëlle Hello, Christine Lac,
Valery Masson, Patrick Lemoigne et al
Météo-France/CNRM et Laboratoire
d’aérologie
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AROME
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
This Arome is running
every day on different domains
MIDPYR since june 2005,
SUDE since september 2005
Replaced by NORE this winter
(plots on ALADIN2 WebSite)
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AROME domains over FRANCE
PARI
BRET
NORE
MIDPYR
SUDE
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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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21 June 2005 Case
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24
15
18
12TU
TU
TU
Inst. AROME rainfalls
L41 AROME wind
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21 June 2005 Case
15 TU
AROME coupled with
Aladin oper
AROME coupled with
Aladin 3DVAR
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Microphysical retrievals : IOP 2A (intense convection)
Simulation (Meso-NH)
12 km
Deep clouds
(x) hail + graupel
(o) hail
( ) rain
(x) hail + graupel
Z > 60
dBz
graupel
(o) hail
( ) rain
100 km
Tabary, 2002
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Deep clouds
Microphysical retrievals : IOP 3 (moderate convection)
18:10 UT
dry snow
hail + graupel
rain
18:30 UT
hail + graupel
snow
rain
Meso-NH simulation
Pujol et al., 2005
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Deep clouds
Quasi-stationnary MCS 13-14 Oct. 1995
OBSERVATIONS
MESO-NH,x=2.5km
x=10km
MESO-NH,
m
m
MESO-NH, x=2.5km
mm
max
max: : 99
25 mm
mm
Initialisation Ducrocq
et al (2000)’s
max : 135 mm
max: 31 mm
Initial conditions: ARPEGE analysis at 18UTC
Cumulated precipitation 01 UTC to 06 UTC the 14th Oct. 1995
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(Ducrocq et al, 2002)
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 TU
AROME 2 last levels cloud
cover
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First case of Fog : 7 January 2005
15 TU
AROME 2 last levels cloud
cover
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Fog
just a few studies with Meso-NH …
But A PRIORITY for AROME
Scientist
Bergot et al., 2005, submitted :
Intercomparison of 1D numerical
models for prediction of the fog
( mp, turbulence, z)
2 events at Paris-CdG. 4 sets of initial
conditions (RS): 18UTC (onset), 21
(thickening), 00 (mature) and 03
(disspation)
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
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Cumulated liquid water content
Fog
Crude test : Modification of the
autoconversion threshold
Meso-NH without
sedimentation of
small droplets
Initialization at 03UTC
Late dissipation due to excessive
rc : lack of gravitational settling
Meso-NH
with
sedimentation
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Bergot et al., 2005, submitted
Fog
For AROME in 2006
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)
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Convective boundary layers
and stratocumulus
•Shallow convection
•Turbulence
•Subgrid clouds
•Microphysics
•Surface
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2005/08/20
09 TU
AROME
Meso-NH
with
SUBGRID
COND +
SHALLOW :
Adjustment
time of 3h in
the closure
Meso-NH
with
SUBGRID
COND +
SHALLOW
30min :
Adjustment
time of
30min
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Coupling with Aladin oper (r0)
Bomex :
w'
'
l
3h
LES
1h
w*
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ARM :
LES
1h
w'
'
l
3h
w*
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ARM : cloud mixing ratio
3h
LES
1h
w*
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BL clouds : Cu
For AROME in 2006
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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Stratocumulus : What’s about the resolutions of AROME ?
x= y= 500m
LES
Cloud water mixing ratio
0h LT
12hLT
SCM
0hLT
0h LT
12hLT
0hLT
x= y= 2.5km
I.Sandu
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BL clouds : Sc
Liquid Water Path
x=500m,z=25m
x=500m,z=50m
x=500m,z=80m
LES
x=500m,z=10m
I. Sandu
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BL clouds : Sc
Preliminary tests in Meso-NH at the resolutions of AROME
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
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. ARPEGEClimat).
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Evaluation CARBOEUROPE
Dry CBL
Forecasts of Meso-NH
(8km) in an operational
mode during the
experiment
La Cape Sud : Comparison MesoNH/RS of BL height (parcel method)
between 6 and 17UTC
25-may
Boundary Layer Height
MESONH vs RS La Cape Sud
26-may
27-may
2500
31-may
06-june
simulated
2000
Weak overestimation
during
the afternoon
07-june
08-juin
09-juin
1500
10-juin
MESO-NH vs PIPER
1000
Weak underestimation during
the morning
500
0
0
500
1000
1500
observed
2000
2500
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Dry CBL
BUT limitations are well-known,
inherent to Eddy-diffusivity
Eddy-diffusivity (local) :
w' ' K
z
with
K
2
L e3
3C p
Too sharpe
inversion due to
lack of topentrainment
Too unstable
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.
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Dry CBL
1. Countergradient with Third order moments
On L
2L
1L
On the TOMs
2L with TOMs
2L without TOMs
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Dry CBL
1.
For AROME in 2006
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 cases
Under 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.
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3. Improvement of the BL89 mixing length in the same way (V.Masson)
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
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