Stochastic Physics Namelist

General options

Option Description
NEW_LSCALE Recommended, set to true if use the correct calculation for decorrelation length scale.
NTRUNC Optional, Spectral resolution (e.g. T126) of random patterns, default is for model to determine proper truncation
LAT_S Optional, number of latitude points for the gaussian grid (must be even), default is for model to determine gaussian grid
LON_S Optional, number of longitude points for the gaussian grid (recommend 2xLAT_S, default is for model to determine gaussian grid
STOCHINI Optional, set to true if wanting to read in a previous random pattern

SPPT options

Option Description
SPPT Amplitudes of random patterns.
SPPT_TAU Decorrelation timescales in seconds.
SPPT_LSCALE Decorrelation spatial scales in meters.
SPPT_LOGIT Should be true to limit the SPPT perturbations between 0 and 2. Otherwise model will crash.
ISEED_SPPT Seeds for setting the random number sequence (ignored if stochini is true)
SPPT_SIGTOP1 lower sigma level to taper perturbations to zero (default is 0.1)
SPPT_SIGTOP2 upper sigma level to taper perturbations to zero (default is 0.025)
SPPT_SFCLIMIT .T.=tapers the SPPT perturbations to zero at model’s lowest level (helps reduce model crashes)
SPPTINT Optional, interval in seconds to update random pattern. Perturbations still get applied every time-step
USE_ZMTNBLCK .T.=do not apply perturbations below the dividing streamline that is diagnosed by the gravity wave drag, mountain blocking scheme
PERT_MP .T.=apply SPPT perturbations to all microphysics specis. If .F. the SPPT is only applied to u,v,t,qv
PERT_RADTEND .T.=apply SPPT perturbations to cloudy sky radiation tendencies. If .F. then do not perturb any radiative tendencies
PERT_CLDS .T.=apply SPPT perturbations to fraction (only works for RRTMG radiation), if using this option set PERT_RADTEND=.F.

SHUM options

Option Description
SHUM Amplitudes of random pattern.
SHUM_TAU Decorrelation timescales in seconds.
SHUM_LSCALE ecorrelation spatial scales in meters.
SHUM_SIGEFOLD e-folding lengthscale (in units of sigma) of specific humidity perturbations, default is 0.2)
SHUMINT Optional, interval in seconds to update random pattern. Perturbations still get applied every time-step
ISEED_SHUM Seeds for setting the random number sequence (ignored if stochini is true).

SKEB options

Option Description
SKEB Amplitudes of random patterns.
SKEB_TAU Decorrelation timescales in seconds
SKEB_LSCALE Decorrelation spatial scales in meters (250)
ISEED_SKEB Seeds for setting the random number sequence (ignored if stochini is true).
SKEBNORM 0-random pattern is stream function, 1-pattern is K.E. norm, 2-pattern is vorticity (default is 0)
SKEB_VARSPECT_OPT 0-gaussian (default), 1-power law (not tested)
SKEB_NPASS number of passes of the del2 smoothing for the dissipation estimate (default is 11, minimum is 3)
SKEB_VDOF the number of degrees of freedom in the vertical for the SKEB random pattern (default is 5)
SKEB_SIGTOP1 lower sigma level to taper perturbations to zero (default is 0.1)
SKEB_SIGTOP2 upper sigma level to taper perturbations to zero (0.025)
SKEBINT Optional, interval in seconds to update random pattern. Perturbations still get applied every time-step

SPP options

Option Description
SPP_VAR_LIST List of parameterizations to be perturbed. Check compns_stochy.F90 for options.
SPP_PRT_LIST SPP perturbation magnitudes used in each parameterization.
SPP_TAU Decorrelation timescales in seconds.
SPP_LSCALE Decorrelation spatial scales in meters.
ISEED_SPP Seeds for setting the random number sequence (ignored if stochini is true).
SPP_SIGTOP1 Lower sigma level to taper perturbations to zero (default is 0.1)
SPP_SIGTOP2 Upper sigma level to taper perturbations to zero (0.025)
SPP_STDDEV_CUTOFF Limit for possible perturbation values in standard deviations from the mean.

Land perturbation options

Option Description
LNDP_TYPE 0, no perturbations. 1, old scheme (Gehne et al. 2019); 2, new scheme (Draper 2021)
LNDP_VAR_LIST List of land perturbations parameters. Check compns_stochy.F90 for options
LNDP_PRT_LIST Perturbation magnitudes used for each parameter perturbations.
LNDP_TAU Decorrelation timescales in seconds.
LNDP_LSCALE Decorrelation spatial scales in meters.
ISEED_LNDP Seeds for setting the random number sequence (ignored if stochini is true).