Introducing LMDZ physical schemes in WRF

Introducing LMDZ physical schemes in WRF L. Fita 1, F. Hourdin, L. Farihead 1 Laboratorie de Météorologie Dynamique, IPSL, Paris-6, UPMC, Tr 44-45 2nd fl., Jussieu, 75005, Paris, France LMD: Reunion Climat February 3rd 2014 Contact: lluis.fita@lmd.jussieu.fr p. 1

Introduction LMDZ has a hydrostatic dynamical core p. 2

LMDZ has a hydrostatic dynamical core LMDZ has a set of physics prepared to run in a GCM Introduction p. 2

LMDZ has a hydrostatic dynamical core LMDZ has a set of physics prepared to run in a GCM Introduction WRF has a primitive equation non-hydrostatic fully compressible dynamical core p. 2

LMDZ has a hydrostatic dynamical core LMDZ has a set of physics prepared to run in a GCM Introduction WRF has a primitive equation non-hydrostatic fully compressible dynamical core WRF has a set of physics prepared to run at very high resolutions ( 0.5km) Include LMDZ physical schemes in WRF in order to: Analyze parameterized/explicitly resolved results with the same platform Analyze the role of a non-hydrostatic dynamics in a GCM/RCM run Analyze the performance of the LMDZ physics at high resolution p. 2

What is an atmospheric Model? Numerical aproximation of the dynamics of the atmosphere Numerical discretization (grid/spectral) of the Navier-Stokes equations Schematic representation of the sub-grid processes Two main types: global circulation models (GCM) and limited area models (LAM) p. 3

Equations Navier-Stokes equations Numerical discretisation i 1,j +1i,j +1 i 1,j i,j i 1,j 1i,j 1 i+1,j What is an atmospheric Model? i+1,j +1 i+1,j 1 p t u t T t ρ 0 gw +γp V = V p ( ) + γp Q + T 0 D θ T C p θ 0 + m ( p ρ x σ p p ) p = V u x σ ( + v f +u m ) y v m x ewcosα uw +D u r earth = V T + 1 ρc p ( p ρ 0 gw)+ Q C p + T 0 θ 0 D θ t + V p ˆχ t = (1 2γ)χ t +γ(χ t+1 + ˆχ t 1 ) ) χ = χ i+1,j χ i 1,j 2 x, χ i,j+1 χ i,j 1 2 y p. 3

Equations-II What is an atmospheric Model? Multi coupled variables on grid points M N Z 5 i [0,M] j [0,N] k(σ) [0,Z] χ [p,u,v,w,t,q] Z N e z e y e x M p. 3

What is an atmospheric Model? Global and limited area models S-N ECMWF NCEP-GFS W-E Limited Area Models: Aladin, Arpege, BOLAM-QBOLAM, COSMO, Hirlam, Lokal, Meso-NH, MM5, RAMS, WRF,... p. 3

Physical processes What is an atmospheric Model? Simplification of complex or not well known processes Processes of different space and time scales Interaction with Primitive eq. WRF (v3.5.1) with a large set of schemes Other options: urban model, FDDA, nudging, wind-farms,... p. 3

WRF Radiation rrtm (1) CAM (3) PBL MRF (1) YSU (2)...... Land Cumulus 5 layer (1) Noah (2)... KF (1) BMJ (2)... Models structure Model call each scheme consecutively Multiple versions of each scheme Flexibility of combination of schemes combi- Inconsistent nations! Micro-physics Kessler (1) WSM 5 (3)... p. 4

LMDZ Radiation Turbulence convective Micro-Physics PBL thermals convection cold pools cumulus Models structure Robust call of physics schemes Computation of climatic values: daily/monthly means Single turbulenceconvective scheme Land output startfi, histfi statistics dump. eof diagf i 2 sets of physics: AR40.0 & NPv3.0 p. 4

1. Perform a flexible introduction of LMDZ physics in WRF Challenges p. 5

Challenges 1. Perform a flexible introduction of LMDZ physics in WRF 2. Perform an easy to use implementation p. 5

Challenges 1. Perform a flexible introduction of LMDZ physics in WRF 2. Perform an easy to use implementation 3. Perform an easy to update (both models) implementation p. 5

Challenges 1. Perform a flexible introduction of LMDZ physics in WRF 2. Perform an easy to use implementation 3. Perform an easy to update (both models) implementation 4. Technical aspects: Minimal changes in LMDZ code Use of WRF compilation structure/framework 5. Usability aspects: Use LMDZ physics as a new WRF set of parameterizations Preserve WRF flexibility and capabilities p. 5

Technical details LMDZ is a full set of physical schemes, deactivation of all WRF schemes!! p. 6

Technical details LMDZ is a full set of physical schemes, deactivation of all WRF schemes!! A WRF LMDZ interface is introduced in WRF code: p. 6

Technical details LMDZ is a full set of physical schemes, deactivation of all WRF schemes!! A WRF LMDZ interface is introduced in WRF code: WRF Interface LMDZ dyn_em/solve_em.f physiq.f T,U,V,Q,pres,... t T, t U, t V, t Q 1. Provide WRF variables to LMDZ physics 2. Transform WRF variables (dimx,dimz,dimy) to LMDZ variables (klon,nlev) [klon=dimx*dimy] 3. Initialize LMDZ variables 4. Obtain state variable tendencies from LMDZ physics 5. Pass WRF initial/boundary variables to LMDZ (avoiding LMDZ input) 6. Retrieve all LMDZ diagnostic variables and include them in WRF (avoiding LMDZ output) p. 6

Work in progress... 1. WRF using LMDZ physics: working on aqua-planet configuration p. 7

Work in progress... 1. WRF using LMDZ physics: working on aqua-planet configuration 2. LMDZ recieving WRF initial conditions: working p. 7

Work in progress... 1. WRF using LMDZ physics: working on aqua-planet configuration 2. LMDZ recieving WRF initial conditions: working 3. LMDZ output in WRF output: partially working p. 7

Work in progress... 1. WRF using LMDZ physics: working on aqua-planet configuration 2. LMDZ recieving WRF initial conditions: working 3. LMDZ output in WRF output: partially working 4. WRF+LMDZ compiled in parallel: not done p. 7

Preliminar results Global aqua-planet runs WRF+LMDZ AR40.0 WRF+LMDZ NPv3.0 p. 8

Preliminar results Regional runs: Zoom on point N 0,0 E Precipitation WRF+LMDZ AR40.0 WRF+LMDZ NPv3.0 p. 8

Preliminar results Regional runs: Zoom on point N 0,0 E Vertical relative humidity WRF+LMDZ AR40.0 WRF+LMDZ NPv3.0 p. 8

Preliminar results Regional runs: Zoom on point N 0,0 E WRF+LMDZ NPv3.0 pbl height WRF+LMDZ NPv3.0 thermal h max p. 8