NAM_TURBn

It contains the characteristics of the turbulence scheme used by the model n. They are included in the declarative module MODD_TURBn.

NAM_TURBn content
Fortran name	Fortran type	Default value
XIMPL	REAL	1.0
CTURBLEN	CHARACTER(LEN=4)	‘BL89’
CTURBDIM	CHARACTER(LEN=4)	‘1DIM’
XCADAP	REAL	0.5
LTURB_FLX	LOGICAL	.FALSE.
LTURB_DIAG	LOGICAL	.FALSE.
LSIG_CONV	LOGICAL	.FALSE.
LRMC01	LOGICAL	.FALSE.
CTOM	CHARACTER(LEN=4)	‘NONE’
XTKEMIN	REAL	\(10^{-6}\)
XCED	REAL	0.84
LLEONARD	LOGICAL	.FALSE.
XCOEFHGRADTHL	REAL	1.0
XCOEFHGRADRM	REAL	1.0
XALTHGRAD	REAL	2000.0
XCLDTHOLD	REAL	-1.0
LCLOUDMODIFLM	LOGICAL	.FALSE.
CTURBLEN_CLOUD	CHARACTER(LEN=4)	‘DELT’
XCOEF_AMPL_SAT	REAL	5.0
XCEI_MIN	REAL	0.001E-6
XCEI_MAX	REAL	0.01E-6
XLINI	REAL	0.1
XCTP	REAL	4.0 if LSTATNW
		else 4.65
XMINSIGS	REAL	1.E-12
LHARAT	LOGICAL	.FALSE.
LPROJQITURB	LOGICAL	.TRUE.
LSMOOTH_PRANDTL	LOGICAL	.TRUE.
NTURBSPLIT	INTEGER	1
LTURB_PRECIP	LOGICAL	.FALSE.
LGOGER	LOGICAL	.FALSE.
XSMAG	REAL	0.2
LDYNMF	LOGICAL	.FALSE.
LTHERMMF	LOGICAL	.TRUE.
LBL89TOP	LOGICAL	.FALSE.
LBL89EXP	LOGICAL	.TRUE.
LLEMARIE21	LOGICAL	.TRUE.

XIMPL : degree of implicitness of the vertical part of the turbulence scheme. (XIMPL = 0.5 corresponds to the Cranck-Nicholson scheme for the vertical turbulent diffusion and 0. to a purely explicit scheme)
CTURBDIM : turbulence dimensionality.
- ‘1DIM’ Only the vertical turbulent fluxes are taken into account. This has to be done for relatively large horizontal gridsizes.
- ‘3DIM’ All the turbulent fluxes are computed, this is necessary for small horizontal gridsizes ( meso-\(\gamma\) scales or LES)
CTURBLEN : type of turbulent mixing length.
- ‘DELT’ If CTURBDIM=’3DIM’, the cubic root of the grid volum is used in 3D simulations and the squared root of the volum in 2D simulations.
- ‘1DIM’, we take \(\Delta z\) in simulation of any dimensionality. This length is always limited to \(\kappa * z\) near the ground.
- ‘BL89’ The mixing length is computed according to the Bougeault and Lacarrere [1989]
- ‘DEAR’ the mixing length is given by the mesh size depending on the model dimensionality, this length is limited to the ground distance and also by the Deardorff mixing length pertinent in the stable cases.
- ‘RM17’ The mixing length is computed according to Rodier et al. [2017]. It is a non-local mixing length combining BL89 with a wind shear term.
- ‘HM21’ resolution-adaptative mixing length is computed according to Honnert et al. [2020] and given by the minimum between RM17 and the horizontal resolution XCADAP \(\sqrt{\Delta x \Delta y}\), where XCADAP is a namelist parameter set to 0.5.
XCADAP : coefficient applied to the HM21 adaptative mixing length
LTURB_FLX : flag to compute and store all the turbulent fluxes on every output synchronous file.
LTURB_DIAG : flag to store diagnostic quantities related to the turbulent scheme on every output synchronous file. (mesh length, Prandtl number, Schmidt number, sources of TKEldots)
LSIG_CONV : Flag for computing Sigma_s due to convection in ice subgrid condensation scheme
LRMC01 : Flag for computing separate mixing and dissipative length in the SBL according to Redelsperger et al. [2001]
CTOM : Consideration of Third Order Moments.
- ‘NONE’: No Third Order moments
- ‘TM06’: Parameterization of Third Order moments of heat fluxes for dry CBL according to Tomas and Masson [2006].
XTKEMIN : minimum value for the TKE (\(m^{2}.s^{-2}\)).
XCED : Constant for TKE dissipation (with CTURBLEN=’RM17’ it is better to use XCED=0.34 according to Rodier et al. [2017]).
LLEONARD : Flag to compute the Leonard terms (instead of K-gradient terms) applied to the vertical fluxes of \(\theta_l\) and \(r_{np}\) (\(r_c\) + \(r_i\) + \(r_v\)). The main effects are an increase of TKE and a decrease of vertical velocity.
XCOEFHGRADTHL : coefficient applied to the vertical turbulent flux of \(\theta_l\).
XCOEFHGRADRM : coefficient applied to the vertical turbulent flux of non precipitating total water mixing ratio \(r_{np}\).
XALTHGRAD : height above ground from which the Leonard terms are applied.
XCLDTHOLD : mixing ratios threshold (\(r_c + r_i\)) from which the Leonard terms are applied. For instance, XCLDTHOLD \(10^{-6}\) kg/kg to apply only on clouds. XCLDTHOLD=-1 to apply everywhere.
LCLOUDMODIFLM : model number where the modification of the mixing length in the clouds is computed.
CTURBLEN_CLOUD : type of turbulent mixing length in the clouds (‘BL89’,’DELT’,’DEAR’: see CTURBLEN for meanings),
XCOEF_AMPL_SAT : saturation of the amplification coefficient,
XCEI_MIN : minimum threshold for the instability index (in kg/kg/m/s, beginning of the amplication),
XCEI_MAX : maximum threshold for the instability index (in kg/kg/m/s, beginning of the saturation of the amplification).
XCTP : Constant for temperature and vapor pressure-correlations (if not defined, the value depends on LSTATNW)
XMINSIGS : minimum value of the variance of the deficit to the saturation out of the turbulence scheme \(kg^2.kg^{-2}\))
LHARAT : flag to activate the RACMO turbulence scheme
LPROJQITURB : flag to project the \(r_t\) tendency on \(r_c\) and \(r_i\)
LSMOOTH_PRANDTL : flag to smooth the Prandtl functions
NTURBSPLIT : number of time-splitting for the computation of horizontal turbulent fluxes
LTURB_PRECIP : flag to activate the turbulent mixing of mixing ratios of snow, graupel, hail and liquid droplets \(r_s\), \(r_g\), \(r_h\), and \(r_r\)
LGOGER: true to compute the Goger terms
XSMAG: dimensionless Smagorinsky constant
LDYNMF: true to take into account a dynamical TKE production from EDMF
LTHERMMF: true to take into account a buoyancy TKE production from EDMF
LBL89TOP: true to limit BL89/RM17 at PBL top (as in ARPEGE)
LBL89EXP: true to use the exposant from the BL89 paper ( which is LOG(16.)/(4.*LOG(XKARMAN)+LOG(XCED)-3.*LOG(XCMFS))). Otherwise 2./3. (False in AROME cycl 50t1)
LLEMARIE21: true to use Lemarie et al. 2021 constant in DELT/DEAR mixing length (\(0.5^{-6/7}\) instead of \(0.5^{-1.5}\))

Note

Diagnostic quantities are written on every synchronuous files (mixing length in clear sky, mixing length modified, amplification coefficient, …) if LTURB_DIAG=.TRUE. in NAM_TURBn.