Réunion Megha-TropiquesToulouse

Simulation Géométrique

Simulation Géométrique

Simulation Géométrique

max max( )m D D maxprojectedArea D

( )?f

●Numerical simulations to

●retrieve β =f°(σ) relation

●Projection 2D

●V(Dmax) A(Dmax)

1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.11

1.5

2

2.5

3

3.5

Relation -

y = 2.2*x - 1.6

y = 2.5*x2 - 6.2*x + 5.3

y = 5.2*x3 - 24*x2 + 38*x - 19

CubeSpheresHexagonal platesHexagonal columnsStars type 1Stars type 2Sphere Agregates test 1Sphere Agregates test 2Sphere Agregates test 3Capped columns plates+platesCapped columns plates+starsCapped columns stars+starsRosettes test 1Rosettes test 2Rosettes test 3Hexagonal plates + rimed spheresHexagonal columns + rimed spheresStars type 2 + rimed spheres

linear quadratic cubic

1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.20.5

1

1.5

2

2.5

3

3.5

4

4.5

Relation -

y = 1.9*x - 1.1

y = 2.3*x2 - 6*x + 5.5

y = 10*x3 - 50*x2 + 82*x - 43

CubeSpheresHexagonal platesHexagonal columnsStars type 1Stars type 2Sphere Agregates test 1Sphere Agregates test 2Sphere Agregates test 3Capped columns plates+platesCapped columns plates+starsCapped columns stars+starsRosettes test 1Rosettes test 2Rosettes test 3Hexagonal plates + rimed spheresHexagonal columns + rimed spheresStars type 2 + rimed spheres--- table from D.Mitchell 1995 --- linear quadratic cubichexagonal plates 15µm<D<100µmhexagonal plates 100<D<3000µmhexagonal columns 30<D<100µmhexagonal columns 100<D<300µmhexagonal columns D>300µmRimed long columns 200<D<2400µmCrystal with sector-like branches(P1b) 10<D<40µmCrystal with sector-like branches(P1b) 40<D<2000µmbroad-branched crystal (Plc) 10<D<10µmbroad-branched crystal (Plc) 100<D<1000µmStellar crystal with braod arms (P1d) 10<D<90µmStellar crystal with braod arms (P1d) 90<D<1500µmdensely rimed dendrites (R2b) 1800<D<4000µmside planes (S1) 300µm<D<2500µmBullet rosettes, 5 branches at -42°C 200<Dw1000µmAggrgates of side planes 600<D<4100µmAggregates of side planes, columns & bullets (S3) 800<D<4500µmAssemblages of planar polycrystals in cirrus clouds 20<D<450µmLump graupel (R4b) 500<D<3000µmHail 5000<D<25000µm

Calcul des loi d’aire in-situ

Calcul de l’aplatissement des particules

Simulation de Réflectivité

RADARÀ

94GHz(Tmatrice +

Mie)

Aplatissement moyen de la distribution des hydrométéores

β information volumique

Réflectivité à94GHz (RASTA) [mm^6/mm^3]

Distribution en taille(PSD)en [#/L/µm]

DDm )(

Restitution de la loi Masse-Diamètre

Avec un pas de 10secondes

Impact de la température sur la loi de masse (et le contenu en glace).

Profil de la loi de masse pour MT1

T > 0

T<0