Classification

Action

Previous

Why

Comments

CYCORA-bis

(whole package)

0

To be installed a.s.a.p., if not yet

CYCORA

Real clean starting point

No back-phasing possible beyond it for all what follows

Code harmonisation

1

PFEVI in the call of ACDROV from APLPAR

Only a marginal impact but no true ascending compatibility though

Modification of the melting process for convective precipitation

2

Code modification in
ACCVIMP replacing (if wanted) a proportion of snowfall depending only on the local temperature by one integrating the effects of all temperatures above via

GCVMLT=1.6E-04,

Equivalent to

GCVMLT=0.

(added parameter)
with a temporary switching role implying internally to

ACCVIMP a LLNEWM=.F. value

LLNEWM changes when GCVMLT>0.

In case of surface inversion one could previously have snow reaching the soil from convective precipitation for a slightly positive surface temperature after crossing very warm layers

The previous situation is still maintained under a local LLNEWM=.F. with a USDMLT=0.125E+05 default

But the switch to the new parameterisation is recommended

The two tunings are equivalent for "standard" vertical temperature profiles

CYCORA-ter

3

Consistency corrections (several of them) in ACHMT and ACCOEFK with communication via APLPAR

To allow further PBL developments in a better environment

No ascending compatibility

Bugged (A) twice
in ACCOEFK, see [12]

Idem

4

New mixing length parameter values, ALMAV=300., BEDIFV=0.05,

UHDIFV=8.E-04,

ALMAV=75., BEDIFV=0.4,

UHDIFV=4.E-04,

Better results at global scale and over oceans

Not appropriate for all conditions (cold continent problems).
Requires local decisions/tuning

Idem

5

New dependency of Kuo-closure on resolution,

GCOMOD=1.,

REFLKUO=10000.,

with LSRCON=.T. unchanged

GCOMOD=0., (was 1. before the introduction of LSRCON)

To restore the correct dependency of both LS and CV precipitations when dx=>0 while keeping the "local" advantages of LSRCON

Highly recommended, especially at high resolution (suppressed for instance some instabilities in ALADIN-France)

Idem

6

GCCSV=0.,

GCCSV=1., (since CYCORA-bis); has been 0. in the past

Better simulation of top of PBL inversions

Recommended, in any case

Idem

7

USURID=0.035,

USURID=0.016,

Tuning for consequences of [3-4-5-6]

The tuning was influenced by [3] & [4] => dependency problem

Reproductibility

8

Bug correction in ACNEBN

Non-reproducibility when changing NPROC

Allows clean test + bug fixing

The results are changed even if mono-proc-mode =>
small but true bug

Blow-up of model fixed + consistency

9

LSRCONT=.T., (on top of LSRCON=.T.) in APLPAR

Equivalent to LSRCONT=.F.
(added switch)

Makes the convective closure more consistent and symmetric for q & s

The bug appeared only with a low truncation and a too weak HDIF; but the syndrom is basic

Bugged (B) in APLPAR, see [19]

Blow-up of model fixed

10

Modified "KUO2" test in ACCVIMPD

Prevents the activation of a "sleeping" design bug in downdrafts computations

The "one in a billion" case; but doing nothing, one might get "lucky";

No ascending compatibility

Preventive action

11

Suppression of false virga in ACCVIMP

Risk spotted while working on [10]

No ascending compatibility

Bug corrections (A)

12

Two of them fixed in
ACCOEFK

Associated retuning of USURID to 0.042

USURID=0.035, (if [4])

Removal of two "coding" bugs

Bug correction compulsory with [3] ; interacts with the retuning of [7]

Anti-fibrillation adaptation to 41 (or 37) levels

13

XMULAF=-1.85,

XMULAF=-1.75,

Change linked to the new dt and dz near the surface

It was discovered on this occasion that this tuning should in principle be redone for each horizontal resolution

Slicing of U and b via the anti-fibrillation scheme cured

14

Code change in ACDIFUS to prevent b to decrease when going downwards => LMULAF=.T.,

Equivalent to LMULAF=.F. (added switch)

The antifibrillation scheme ceases to create stationary spurious PBL wind patterns

Necessary if one wants to run with long time steps or XMULAF further away from -2.

XMULAF should be retuned also for that change

Avoiding 0/0 risk

15

Change ZEPS1 in
ACCVIMP and
ACCVIMPD to 1.E+03

1.E-01

Better security

Hardly modifies the results

Model blow-up cured

16

ZALF in ACCVIMPD imposed smaller or equal than in ACCVIMP 

One avoids trying to reach the ground with a downdraft across a well mixed and very dry PBL

For the time being the precipitations spuriously reach the ground in such a case, with this fix

Sleeping weakness probably exacerbated by the bug in LSRCONT

Further treatment required soon (see below [20-21-22])

No ascending compatibility

Clarification of the downdraft's role

17

Added protection in
ACCVIMPD against a risk of sub-cloud precipitation-generating downdraft computations (especially when [15-16] are active)

This weakness existed from the start of the downdraft parameterisation but its role was probably minor up to now

No ascending compatibility

Safety action

18

Equivalent of [11] for downdrafts in ACCVIMPD

May be superfluous because never used

No ascending compatibility (on the paper) though

Classification

Action

Previous

Why

Comments

Bug correction (B)

19

Avoid the temporary double substraction of LS precipitations in the CV closure computation in APLPAR

Removal of one "phasing" bug

Bug correction compulsory with [9]

Additional correction for items [15] and [16]

20

Avoiding a "zero" total effect in ACCVIMP and
ACCVIMPD when the ZEPS1 limit is acting

Change physically necessary since the strong increase of the protection values via [15]

Small impact

No ascending compatibility

Idem

21

Modulated reintroduction of a non-organised sub-cloud evaporation for convective precipitations via
RCVEVAP=0.25
in ACCVIMP

RCVEVAP did not exist but LCVEVAP (currently .F. and now disappearing) did and we have the equivalence:

.F. <-> 0. , .T. <-> 1.

Intermediate situations are now possible

With item [16] one may have convective precipitations reaching the surface despite crossing very dry levels (that combination itself justifying the activation of the "ZALF" protection)

The idea is to have at the start the same value for RCVEVAP than for GDDEVA, in order to get the best possible compensation between the two effects of [16] and [21]

Idem

22

Updated protection against negative precipitation fluxes in ACCVIMPD

With the activation of non-zero RCVEVAP a yet unprotected consequence of [17] becomes far more likely to lead to negative fluxes

Hardly modifies the results even if clearly necessary

No ascending compatibility

Introduction of an optional parameterisation of "shear-linked" convection

23

Code modifications in ACTQSAT, APLPAR ,
ACCVIMP and
ACCVIMPD to activate this parameterisation with LSLC=.T.

Equivalent to LSLC=.F. (added switch)

In case of explosive sub-synoptic developments in ALADIN (and ARPEGE) there seem to be often an accumulation of "cross-zero" PVe that cannot be released by explicit motions until "too late";

Increased need with higher H-resolution

With respect to a pure "slantwise"; convection case, the parameterisation does not need information from neighbouring points (nor about the Coriolis parameter f) because of some simplifications and because we modify the target profiles at equal environment while the actual process rather works the other way round (with nearly the same impact)

Will need retuning of convective and  USURID/USURIDE values

Optional complement to the anti-fibrillation scheme concerning shallow convection

24

Code modifications in
ACCOEFK and APLPAR (& above) to be able to activate this option with LCVPPLIS=.T.

Equivalent to LCVPPLIS=.F.
(added switch)

Since the anti-fibrillation scheme cannot treat the "scintillations" of the on/off behaviour of the shallow-convection computation inside the vertical diffusion, the additional term of this effect ought to be time-smoothed

This is an ad-hoc treatment for a problem that shall require a change of parameterisation (mass-flux formulation ?)

Changes the global moisture cycle even if less than the "shear-linked" convection parameterisation of [23]

Introduction of a tunable "moist gustiness effect" and lower tuning of the "dry" equivalent effect

25

This new parameterisation touches ACHMT,
ACCOEFK and APLPAR
( & above)

There are four associated new namelist parameters:

The switch LRRGUST for activation,

UTILGUST=0.125 (characteristic speed), RRGAMMA=0.8 (exponent) and RRSCALE=1.15E-04 (scaling rainfall rate ~10 mm/day)

Activation should be associated with a reduction of VZ0CM

Equivalent to LRRGUST=.F.
(added switch)

Current value for the "dry gustiness" roughness length: VZ0CM=1.5E-04

This parameter was already once at a 0.5E-04 value in the past

TOGA-COARE measurements have shown a strong enhancement of surface and PBL fluxes through gust-type motions in case of strong rainfall and low wind shear

A self-regulating and really monotonous version of the raw parameterisation of this effect has been developed for the ARPEGE/ALADIN physics

Unlikely to play a big role in ALADIN (continental mid-latitude situations)

The need to tune down VZ0CM there should thus be also reassessed