malardela

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

Slide2: 

AROME Aladin dynamical core

AROME Physics: 

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

The Daily Arome prototype: 

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

Slide5: 

AROME domains over FRANCE

Deep Clouds: 

Deep Clouds Microphysics Coupling with the dynamics

Slide7: 

An AROME good forecast : 21 June 2005

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Inst. AROME rainfalls L41 AROME wind 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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12 km 100 km Tabary, 2002 (x) hail + graupel (o) hail ( ) rain (o) hail (x) hail + graupel ( ) rain Microphysical retrievals : IOP 2A (intense convection)

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hail + graupel dry snow rain Pujol et al., 2005 18:10 UT 18:30 UT Microphysical retrievals : IOP 3 (moderate convection)

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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 OBSERVATIONS (Ducrocq et al, 2002) Initial conditions: ARPEGE analysis at 18UTC

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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)

Fog (and low clouds): 

Fog (and low clouds) Microphysics Radiation Vertical resolution Turbulence in stable layers

Slide15: 

First case of Fog : 7 January 2005 09 TU AROME 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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Bergot et al., 2005, submitted : Intercomparison of 1D numerical models for prediction of the fog ( mp, turbulence, Dz) 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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Bergot et al., 2005, submitted 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

Convective boundary layersand stratocumulus: 

Convective boundary layers and 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)

Bomex : : 

Bomex : LES

ARM : : 

ARM : LES

ARM : cloud mixing ratio: 

ARM : cloud mixing ratio LES

Slide25: 

For AROME in 2006 Modification of the KFB closure (w*, Grant et al, 1999) Improvement of subgrid cloud representation (Bechtold et al, 1995, Lenderink and Siebesma, 2000) Test of EDMF scheme in Meso-NH (P.Soares)

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Stratocumulus : What’s about the resolutions of AROME ? I.Sandu

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Liquid Water Path I. Sandu

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For Arome , second part of 2006 Sensitivity tests on vertical resolution for cloud-top entrainmentAdditional levels to L41? Interest of an entrainment parametrization (Lock, 2001, 2004. ARPEGE-Climat). 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 Dz than lower Dx Main impact of Dz at the top of Sc (entrainment) than beneath

Slide29: 

Evaluation CARBOEUROPE Forecasts of Meso-NH (8km) in an operational mode during the experiment

Slide30: 

The K-diffusion doesn’t take into account countergradient. Entrainment is not treated explicitly in the K-diffusion approach. But diffusion remains necessary, for transition to neutral or stable BL. BUT limitations are well-known, inherent to Eddy-diffusivity

Slide31: 

1. Countergradient with Third order moments

Slide32: 

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 ?) EDMF scheme : evaluation of the impact in Meso-NH during the 1st sem.2006 (In collaboration with P.Soares) Comparison EDMF/TOMS on the same cases

Summary: 

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