Documentation of the Changes in the COSMO-Model
Version 5.09a

18.05.2021

1. Preparations for the New Multi-Layer Snow Scheme SNOWPOLINO

(by Sascha Bellaire, Varun Sharma)

NOTE:
This scheme is not yet active! These are only preparatory steps!

Added new Fields

The following new fields have been added for the multi-layer snow scheme SNOWPOLINO. The fields are also defined in the blocked data structure (for now and new time level). The vertical dimension of the multi-layer variables is ke_snow. All fields are available for input/output.

shortname	COSMO variable	Explanation	Unit
`TofSNW_LTOP_M`	`t_sn`	multi-layer snow temperature	K
`ICEinSNW_VC_M`	`theta_i`	volumentric ice content	-
`H2OinSNW_VC_M`	`theta_w`	volumentric water content	-
`AIRinSNW_VC_M`	`theta_a`	volumentric air content	-
`DZ_SNOW_M`	`dzm_sn`	layer thickness	m
`H_NEWSNOW_M`	`hn_sn`	new snow amounts (storage)	m
`N_SNOW_M`	`top_sn`	index of first (top) snow layer	-

NOTE:
The field TofSNW_LTOP_M (temperature of snow level top) is different from the already existing field T_SNOW_M. While T_SNOW_M is defined as a level (only typeOfFirstFixedSurface set in GRIB 2), TofSNW_LTOP_M is a layer, for which both meta data, typeOfFirstFixedSurface and typeOfSecondFixedSurface are set. But the value is defined at the layer top.

New (and replaced) Namelist Variables

Up to now the namelist switch lmulti_snow was used to switch on or off the already implemented multi-layer snow scheme from Ekaterina Machulskaya. To account also for the new multi-layer snow scheme SNOWPOLINO, this switch has been replaced by an integer variable itype_snow. In addition, a new switch for the initialization of SNOWPOLINO, itype_snow_start, has been implemented.

itype_snow: type of snow scheme to use (replaces lmulti_snow)
1. (default) traditional single layer scheme
2. multi-layer snow scheme by Ekaterina Machulskaya (former lmulti_snow)
3. multi-layer snow scheme SNOWPOLINO
itype_snow_start: type of cold start for SNOWPOLINO (only active for itype_snow=3)
1. no cold start: fields for itype_snow==3 have to be read
2. hard cold start: all snow is removed and fields initiated to zero
3. soft cold start: (default) state snow cover is estimated based on available analysis fields T_SNOW, W_SNOW, RHO_SNOW

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2. Preparations for the Urban Parameterization TERRA_URB

(by Hendrik Wouters, Mikhail Varentsov, Ulrich Schättler)

NOTE:
This scheme is not yet active! These are only preparatory steps!

Added new Fields

The climate scenarios for CMIP6 feature the so-called "Shared Socioeconomic Pathways" emission scenarios. To faciliate the downscaling of CMIP6 simulations, several of the corresponding greenhouse-gas concentrations can be choosen by setting the namelist parameter ico2_rad to values between 11 and 19. The following scenarios are available:

The following new fields have been added for the urban parameterization TERRA_URB. Fields with an entry "b" also exist in the blocked data structure. And only fields with a given shortname are available for I/O.

shortname	COSMO variable	blocked	Explanation	Unit
FR_PAVED	isa	b	total impervious surface-area index	( - )
	isa_uc		impervious surface-area fraction in the urban canopy (mostly 1)	( - )
	frc	b	surface fraction of the tiles	( 1 )
	sa_uc	b	surface-area fraction of the urban canopy (buildings and pavements)	( - )
	w_imp	b	impervious water storage	(kg m-2)
	w_isa	b	this is the same as w_imp, but multiplied by isa	(kg m-2)
	kbmo	b	inverse Stanton number	( - )
	ai_uc	b	surface area index of the urban canopy (> 1)	( - )
	alb_red_uc	b	albedo reduction factor for the urban canopy	( - )
AHF	ahf_an		anthropogenic heat flux (annual mean)	( 1 )
	ahf_now		anthropogenic heat flux of the current time step	( 1 )
	t_g_atm	b	weighted surface temperature for lterra_urb	( K )
URB_FR_BLD	urb_fr_bld	b	Building area fraction with respect to urban tile	( - )
URB_H2W	urb_h2w	b	Street canyon H/W ratio	( m/m )
URB_H_BLD	urb_h_bld	b	Building height	( m )
URB_ALB_TH	urb_alb_th	b	Urban material thermal albedo	( % )
URB_ALB_SO	urb_alb_so	b	Urban material solar albedo	( % )
URB_HCAP	urb_hcap	b	Volumetric heat capacity of urban material	(Jm-3K-1)
URB_HCON	urb_hcon	b	Heat conductivity of urban material	(Wm-1K-1)

New Namelist Variables

To control the urban parameterization TERRA_URB, the following namelist variables have been implemented:

lterra_urb: to switch on / off the urban-canopy land-surface scheme (default: .FALSE.)
lurbfab: to switch on/off the urban fabric (in a bulk approach) (default: .TRUE.)
itype_ahf: to choose the type of anthropogenic heat
1. no anthropogenic heat flux
2. anthropogenic heat according to Flanner (2009) (default)
itype_kbmo_uf: to choose the bluff-body thermal roughness length parametrization
1. standard SAI-based turbtran;
2. Brutsaert/Kanda; (default)
3. Zilitinkevich
itype_eisa: to choose the type of evaporation from the impervious surface:
1. evaporation just like bare soil;
2. no evaporation;
3. PDF-based puddle evaporation (Wouters et al., 2015) (default)

NOTE:
In a first implementation another namelist variable ntiles was used. But this solely depends on lterra_urb and cannot really be chosen by the user. Therefore it was removed again.

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3. Additional Adaptations for MESSy

(by Astrid Kerkweg)

For MESSy, the local field fr_wi_b from TERRA is required also outside of TERRA.

In addition, some modifications have been done in lmorg.f90:

trcr_swap now again follows directly the time level shift
local variable xtte renamed to zxtte
bugfix in an if-statement for trcr_get
flag added to call messy_read_restart (AK)

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4. Added a new internal switch lcalc_wmaxtrack

(by Ulrich Schättler)

For all track variables but wmaxtrack (W_CTMAX), internal logical switches already have been implemented to control, whether they have to be computed. These switches are set to .TRUE., if the corresponding shortname appears in an output list. lcalc_wmaxtrack just has been forgotten before.

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5. Technical Changes and Bug Fixes

netcdf_io.f90:
- Correct cell_methods attribute for soil variables in netCDF output (BR)
- Correct unit of vcoord ("m" instead of "Pa" for option 2/3) (AK)
radiation_interface.f90:
- Treatment of for_e and for_d only for lforest=T (AK)
- Removed lmulti_snow: also in this case, t_snow is set and can be used (US)
- Put CONTAINS at the end of SR radiation_organize inside the ifdef SER_PHY to avoid empty section afterwards (US)
radiation_utilities.f90:
Removed lmulti_snow: also in this case, t_snow is set and can be used.
sfc_terra.f90:
Remove variable flux_ksop05_neg from line 4229: DO-loop for "lowest active hydrological layer ke_soil_hy-1", where it is not really used (US).
sfc_interface.f90,
sfc_terra_data.f90:
Introduced vpp-equivalents for model parameters from data_constants in sfc_terra_data and use them from there. Some of them are also used in the new scheme SNOWPOLINO.
src_obs_gnss.f90:
Removed izerror from SR set_geoid_ascii and used istat instead.
src_perturb_fields.f90: Use lalloc_tke instead of ALLOCATED(TKE).
src_sfcana.f90:
Modified call to exchg_boundaries to exchange 3 boundary lines (not only 2).
src_traj.f90:
Modifications for checking idef_stat in SR intp_traj: ask for P within idef_stat=1 and set zkdim for all variables within idef_stat=0

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6. Changes to the Namelists

Group	Name		Meaning	Default
`/PHYCTL/`	`itype_snow`	NEW	Type of snow scheme to use (replaces `lmulti_snow`) (default) traditional single layer scheme multi-layer snow scheme by Ekaterina Machulskaya (`former lmulti_snow`) multi-layer snow scheme SNOWPOLINO	`1`
	`itype_snow_start`	NEW	Type of cold start for SNOWPOLINO (only active for `itype_snow=3`) no cold start: fields for `itype_snow==3` have to be read hard cold start - all snow is removed and fields initiated to zero soft cold start - state snow cover is estimated based on available analysis fields `T_SNOW`, `W_SNOW`, `RHO_SNOW`	`2`
	`lterra_urb`	NEW	To switch on/off the urban parameterization.	`.FALSE.`
	`lurbfab`	NEW	To switch on/off the urban fabric (in a bulk approach).	`.TRUE.`
	`itype_ahf`	NEW	Type of anthropogenic heat no anthropogenic heat flux (default) anthropogenic heat according to Flanner (2009)	`1`
	`itype_kbmo_uf`	NEW	Bluff-body thermal roughness length parametrization standard SAI-based turbtran Brutsaert/Kanda Zilitinkevich	`1`
	`itype_eisa`	NEW	Type of evaporation from the impervious surface evaporation just like bare soil no evaporation PDF-based puddle evaporation (Wouters et al., 2015)	`2`

7. Changes of Results

NONE

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