Last updated: September 2006
| Name | Dimensions | Element Number | Level type | Table | Description | Comments |
|---|---|---|---|---|---|---|
| FR_LAKE | - | ee=55 | lvtyp=1 | tab=202 | Lake fraction | FR_LAKE must be consistent with the land-sea mask used |
| DEPTH_LK | m | ee=96 | lvtyp=1 | tab=201 | Lake depth | Each lake present in the LM domain is characterised by its mean depth |
| FETCH_LK | m | ee=97 | lvtyp=1 | tab=201 | Wind fetch | Currently unused |
| GAMSO_LK | m-1 | ee=92 | lvtyp=1 | tab=201 | Attenuation coefficient of lake water with respect to solar radiation | Currently unused |
| DP_BS_LK | m | ee=93 | lvtyp=1 | tab=201 | Thickness of the thermally active layer of bottom sediment | Currently unused |
| T_BS_LK | K | ee=190 | lvtyp=1 | tab=201 | Temperature at the bottom of the thermally active layer of bottom sediment | Currently unused |
The lake fraction FR_LAKE (could also be referred to as "lake-sea-land mask'") is the area fraction of a given LM grid box covered by lake water. Since LM (LME, LMK) does not use a tile approach to account for the sub-grid scale land-use features, only the grid boxes with the lake fraction in excess of 0.5 are considered as lake-type boxes. The lake depth field DEPTH_LK contains mean depths of lakes that are present in the LM domain. For the sea and land grid boxes, DEPTH_LK is set to a dummy value of -1.
For lack of better estimates, the FLake external parameters FETCH_LK, GAMSO_LK, DP_BS_LK and T_BS_LK are assigned their defaults values that are kept constant is space and time. FETCH_LK is set to a large value of 104 m that basically eliminates the dependence of the aerodynamic roughness of the water surface on the wind fetch. GAMSO_LK is set to 3 m-1 that corresponds to the absorption of 95% of solar radiation in the uppermost metre of lake water. DP_BS_LK and T_BS_LK are set to 10 m and 277.13 K (temperature of maximum density of fresh water), respectively. Notice that FETCH_LK is not required if the current LM surface-layer parameterization scheme (Raschendorfer 1999, 2001) is used instead of SfcFlx to compute the surface fluxes of momentum and of sensible and latent heat. DP_BS_LK and T_BS_LK are not used if the bottom-sediment module of FLake is switched off.
The above default values should be replaced by improved estimates as the required empirical information becomes available. In order to save computational resources, FETCH_LK, GAMSO_LK, DP_BS_LK and T_BS_LK are not included into the list of the LM input-output variables (although such possibility is foreseen and the corresponding GRIB fields are defined). The respective physical variables are handled internally by LM.
| Name | Dimensions | Element Number | Level type | Table | Description | Comments |
|---|---|---|---|---|---|---|
| T_MNW_LK | K | ee=194 | lvtyp=1 | tab=201 | Mean temperature of the water column | |
| T_WML_LK | K | ee=193 | lvtyp=1 | tab=201 | Mixed-layer temperature | |
| T_BOT_LK | K | ee=191 | lvtyp=1 | tab=201 | Bottom temperature (temperature at the water-bottom sediment interface) | |
| H_ML_LK | m | ee=95 | lvtyp=1 | tab=201 | Mixed-layer thickness | |
| C_T_LK | - | ee=91 | lvtyp=1 | tab=201 | Shape factor with respect to the temperature profile in the thermocline | |
| T_B1_LK | K | ee=192 | lvtyp=1 | tab=201 | Temperature at the outer edge (bottom) of the upper layer of bottom sediment | Currently unused |
| H_B1_LK | m | ee=94 | lvtyp=1 | tab=201 | Thickness of the upper layer of bottom sediment | Currently unused |
| Name | Dimensions | Element Number | Level type | Table | Description | Comments |
|---|---|---|---|---|---|---|
| T_SNOW | K | ee=203 | lvtyp=1 | tab=201 | Snow surface temperature (temperature at the air-snow interface) | |
| H_SNOW | m | ee=66 | lvtyp=1 | tab=2 | Snow thickness | |
| T_ICE | K | ee=215 | lvtyp=1 | tab=201 | Ice surface temperature (temperature at the snow-ice or, if there is no snow above ice, at the air-ice interface) | Currently used by LM only if "llake=.TRUE." |
| H_ICE | m | ee=92 | lvtyp=1 | tab=201 | Ice thickness | Currently used by LM only if "llake=.TRUE." |
| T_S | K | ee=85 | lvtyp=111 | tab=2 | Surface temperature | |
| T_G | K | ee=11 | lvtyp=1 | tab=2 | Weighted surface temperature | |
| T_SO | K | ee=197 | lvtyp=111 | tab=201 | Soil temperature (multi-layer soil model) | Only the temperature of the uppermost soil layer is used (lv=0) |
At present, the bottom-sediment module of FLake is switched off. T_B1_LK and H_B1_LK are kept constant equal to their reference values of 277.13 K and 10 m, respectively. T_B1_LK and H_B1_LK are not included into the list of the LM input-output variables (although such possibility is foreseen and the corresponding GRIB fields are defined) and the respective physical variables are handled internally by LM.
In the current LM-FLake configuration, snow over lake ice is only accounted for parametrically through changes in the ice surface albedo with respect to solar radiation. For the lake grid boxes, T_SNOW is set equal to T_ICE and H_SNOW remains zero. In case a lake-type grid box is free of ice, T_ICE is set to 273.15 K (fresh-water freezing point) and H_ICE is zero. For the sea and land grid boxes, T_ICE is set to 273.15 K, T_MNW_LK, T_WML_LK and T_BOT_LK are set to 277.13 K, H_ICE and H_ML_LK are set to zero, and C_T_LKis set to its minimum value of 0.5.
Namelist PHYCTL, (file namelst_phyctl)
Logical switch "llake" is added that should be set .TRUE. to use FLake (note that default
is "llake=.FALSE.")
Namelist GRIBOUT, (files namelst_gribout_forecast and namelst_gribout_nudgecast)
The following variables are added to the LM output list (yvarml= ... ):
'T_ICE', 'H_ICE', 'T_MNW_LK', 'T_WML_LK', 'T_BOT_LK', 'C_T_LK', 'H_ML_LK'
Namelist GRIBOUT, (files namelst_gribout_nudge)
The following variables are added to the LM output list (yvarml= ... ):
'FR_LAKE', 'DEPTH_LK', 'T_ICE', 'H_ICE', 'T_MNW_LK', 'T_WML_LK', 'T_BOT_LK',
'C_T_LK', 'H_ML_LK'