Modélisation du cycle de l’ozone dans la haute troposphère : impact des NOx produits par les éclairs.

C. Mari, JP. Pinty, P. Mascart, J. Duron, C. Barthe, JP Chaboureau, F. Gheusi, M. Tressol and T. Fehr (DLR)

- Motivations - Paramétrisation des LiNOx dans Méso-NH- Applications à TOGA-COARE, TROCCINOX et STERAO- Perspectives

Méso-NH – Réunion utilisateurs -Toulouse 2005

Comprendre le bilan de l’ozone troposphérique

NOx : catalyseurs indispensables pour la production de l’O3 !

Réduire l’incertitude sur les sources de NOx

(Lee et al., 1997)

Paramétrisation des LiNOx dans Méso-NH(JP Pinty et T. Fehr)

• Lightning frequency (Price and Rind 1992) / Cloud Top Height

• IC/CG rate (Price and Rind, 1994) / Cold cloud thickness

• P(CG) = 6,7 x 1026 molecules of NO / flash, P(IC) = P(CG) / 10 (Price et al., 1997)

• LNOx in updrafts and/or in downdrafts

• Perfectly coherent with transport and scavenging

0°C

-10°C

IC

CG

Updrafts

Downdrafts

Cloud Top

Long-term simulations 1D / TOGA-COARE

Upper troposphere: Accumulation

Free troposphere:Competition LNOx vs. convective transport

PBL: Increase of NOxdue to downdraft transport of LNOx

NO2 (LiNOx) – NO2 (No LiNOx)

Long-term simulations 1D / TOGA-COARE

O3 (LiNOx) - O3 (NO LiNOx)

LNOx = local and sporadic eventbut integrated effect in space and time for ozone

Meso-NH Set-up for regional (low-resolution) simulationsEU-TROCCINOX

• One single domain (same as forecast mode)• horizontal grid: 102 x 102 points at 30 km resolution

• 72 levels: from 40 m (bottom) up to 600 m (top)

• Physics

• turbulence: CBR TKE 1D scheme

• convection: Bechtold’s scheme (incl. scavenging and LiNOx)

• microphysics: Pinty-Jabouille, subgrid cloudiness

• surface: ISBA and TEB

• radiation: ECMWF

• Initialization/coupling with ARPEGE-MOCAGE analysis

• Lagrangian tracers

• Chemistry• ReLACS scheme (37 species)

• dry deposition: Wesely

• emissions: EDGAR/GEIA (1°x1°)

(except for BB, Yevich and Logan 2003)

03/03/04Local convection flight in the afternoon

03/03/04Morning flight survey

04/03/04Aged NOx plume in the afternoon

Modelling of LNOx in MNHC at high resolution[ JP Pinty, C. Mari, C. Barthe and JP Chaboureau]

The STERAO intercomparison case[courtesy of M. Barth, NCAR)

http://box.mmm.ucar.edu/individual/barth/Chem_Convec_Intercomparison/slide1.html

Set-up of Méso-NH

• Domain

• horizontal grid : 120 x 120 points at 1 km resolution with open LBC

• 50 levels : from 70 m (bot) up to 600 m (top) with wave damping

•Physics

• transport with MPDATA scheme

• microphysics: Pinty-Jabouille

• electricity: Barthe-Pinty-Molinié

• gas scavenging & LiNOx: Mari-Pinty

• 3D turbulence (TKE): Cuxart-B-R

• Initialization

• R/S with 3 warm bubbles (3K)

• profiles of HCHO, H2O2, HNO3

• profiles of CO, NOx, O3

• 3 hour run on the 12 LINUX cluster @ LA

Ice and Wind fieldsT=1 hour @ Z=10 km

Convective Transport and scavenging

75 ppb<CO<130 ppb

Time = 1 hour Time = 2.5 hours

HNO3

http://box.mmm.ucar.edu/individual/barth/Chem_Convec_Intercomparison/slide1.html

Perspectives

● Modèle couplé transport / lessivage / éclairs / chimie dans la convection, complet et réaliste

● Tests de sensibilité 1D (stage de H. Luitjing au LA )

● Amélioration de la paramétrisation: approche plus physique, comparaison avec des simulations explicites de type STERAO (stage post-doctoral C. Barthe)