LMDZ Single Column Model what is it why

LMDZ Single Column Model + what is it ? + why is it interesting ? + List of 1 D cases + how to install and run it ? M-P Lefebvre and LMDZ team

Use of 1 D cases Observation Test case, field campaign experiment luati a v E on Explicit simulations, Grid cell, 20 -100 m Evaluation « Large scale » conditions imposed Climate model, parameterizations, « single-column » mode Courtesy F. Hourdin

3 D is a collection of many “single column models”, covering earth and interaction with each other through a set of rules known as “large scale dynamics”. In a 1 D model, there is no dynamics. We use observations or model output or idealized forcing to impose forcing at the boundary of the column.

LMDZ model in 1 D mode - We impose large scale conditions. - Duration of the case varies from few hours to few months - We study parameterizations in a given environment. z~20 km Δz = 30 m - 1 km T (K) Q (g/kg) Large scale forcings (constant or not): Temperature, humidity, Wind advection Δx = 50 -300 km Surface conditions: Surface fluxes or Surface temperature

Why use SCMs ? + simplicity: technical and understanding, usable on any labtop + it's a useful tool for parameterization development: shallow convection, deep convection, transition from stratocumulus to cumulus, stable boundary layer, radiation. . . + we can compare results to observations or to explicit simulations (CRM, LES) + then we go back to GCM and test new parameterizations. . . + hierarchy of models: SCM, CRM, AGCM, GCM. . .

shallow convection Arm_cu (diurnal cycle of shallow cumulus over land) Rico (shallow precipitating cumulus over sea) Ayotte (convective boundary layer ) Arm_cu case - Cloud fraction

Stratocumulus and transition to cumulus Sandu (transition case with 3 options according to variation of SST) • Fire (diurnal cycle of stratocumulus) Fire case: Cloud fraction (%) Top: standard version Bad representation because not Enough entrainment at the cloud top Bottom: version developped by A. Jam

Deep convection: Over ocean: • Toga • case_e (part of Toga) • TWPICE Case Vertical speed Precipitation

LES LMDZ_AR 4_L 39 AMMA case: Thetal tendencies due to all schemes (K/j) Deep convection: Over land: • Hapex • AMMA • Idealized case: eq_rad_conv (RCE) LMDZ_NP_L 70

How to proceed ? + install LMDZ 3 D with install. sh + install LMDZ 1 D with instal 1 d. sh. * this script adds some routines specific to 1 D * creates phy 1 D directory * compiles * runs 3 cases (toga, twpice, arm_cu) and show cloud cover plot

Some changes. . . in ~/LMDZ 20131121. trunk/modipsl/modeles/LMDZ 5/libf drwxr-xr-x 13 mpllmd lmdjus 4096 Nov 29 17: 18. drwxr-xr-x 10 mpllmd lmdjus 4096 Nov 29 19: 32. . drwxr-xr-x 3 mpllmd lmdjus 4096 Nov 21 16: 30 bibio drwxr-xr-x 3 mpllmd lmdjus 4096 Nov 21 16: 30 cosp -rw-r--r-- 1 mpllmd lmdjus 888775 Nov 29 19: 29 create_make_gcm. log -rw-r--r-- 1 mpllmd lmdjus 67587 Nov 29 19: 27 create_makeg_gcm. log drwxr-xr-x 3 mpllmd lmdjus 8192 Nov 21 16: 30 dyn 3 dmem drwxr-xr-x 3 mpllmd lmdjus 8192 Nov 21 16: 30 dyn 3 dpar drwxr-xr-x 3 mpllmd lmdjus 4096 Nov 21 16: 30 filtrez drwxr-xr-x 4 mpllmd lmdjus 97 Nov 29 19: 32 grid drwxr-xr-x 4 mpllmd lmdjus 12288 Nov 29 19: 23 phy 1 d = phylmd + 1 D specific routines drwxr-xr-x 3 mpllmd lmdjus 4096 Nov 21 16: 30 phydev drwxr-xr-x 4 mpllmd lmdjus 8192 Nov 21 16: 30 phylmd drwxr-xr-x 6 mpllmd lmdjus 92 Nov 21 16: 30. svn In phy 1 d, you can modify the code

Some changes also. . . in ~/LMDZ 20131121. trunk/1 dcases drwxr-xr-x drwxr-xr-x drwxr-xr-drwxr-xr-x 8 mpllmd lmdjus 4096 Dec 3 10: 28 amma 4 mpllmd lmdjus 4096 Dec 3 10: 50 arm_cu 5 mpllmd lmdjus 4096 Dec 3 11: 55 ayotte 3 mpllmd lmdjus 4096 Dec 3 12: 12 case_e 3 mpllmd lmdjus 4096 Dec 3 12: 14 eq_rd_cv 5 mpllmd lmdjus 4096 Nov 29 19: 29 fire 3 mpllmd lmdjus 4096 Nov 29 19: 29 hapex 92_init 4 mpllmd lmdjus 4096 Nov 29 19: 29 rico 5 mpllmd lmdjus 4096 Nov 29 19: 29 sandufast 5 mpllmd lmdjus 4096 Nov 29 19: 29 sanduref 5 mpllmd lmdjus 4096 Nov 29 19: 29 sanduslow 5 mpllmd lmdjus 4096 Nov 29 19: 30 toga 4 mpllmd lmdjus 4096 Nov 29 19: 31 twpice Here, you can compile the model and run your favorite case

What can you do in each case directory ? + compile with compile. x: choose level number + profils and forcings (ascii files or netcdf files) + def files + readme + execute with xqt. x or mr file + get results in netcdf files (histhf. nc) + compare to LES results in resul_LES

In LMD, we used these cases to develop New Physics version. For 2 cases, Arm_cu and Rico, we compare results of « standard physics » (CMIP 3), « new physics » (CMIP 5) and LES model. Shade= cloud cover Contour= specific humidity (g/kg)

Rico case : Sensitivity Tests to vertical discretization and time step

Thank you !