Here you will find some general information on the chosen data and file formats, in addition to information on the ALMA convention. For specific information, see modelling protocol.
Content
NetCDF
NetCDF is the chosen data format both for the input data and the output data. A good source of documentation on the netCDF format can be found at http://www.unidata.ucar.edu/software/netcdf. The online user manual is filled with example code blocks. Also, Jan Polcher has written and assembled some general software for reading and writing netCDF format (see http://www.lmd.jussieu.fr/~polcher/ALMA/alma_bazar.html). The files are to be submitted in compressed formats. Please use the Linux/UNIX compress or gzip (GNU zip) to compress the output files. For those using Windows, WinZip is also acceptable.
Data convention
The ALMA data exchange convention (http://www.lmd.jussieu.fr/~polcher/ALMA/), which has been used in e.g. PILPS and GSWP projects, will be used. The additional variables requested for the simulations with human impacts are listed and described in Table 2 below.
Table 1: Convention for model output data. ALMA convention. Be aware that this list may include more variables than should be submitted. See "Modelling Protocol" for the list of variables that should be submitted for your modelling purpose.
Variable | Description | Definition |
Units |
Positive dir. |
Precip | Precipitation rate |
Average of the total precipitation (rainfall and snowfall) over a time step and grid cell, i.e. the standard ALMA Snowf and Rainf are added. |
kg/m2s |
Downward |
Snowf | Snowfall |
Average of the total snowfall over a time step and grid cell |
kg/m2s |
Downward |
Evap |
Total evapotranspiration |
Sum of all evaporation sources, averaged over a grid cell |
kg/m2s |
Upward |
Qs |
Surface runoff |
Runoff from the landsurface and/or subsurface stormflow. This variable should include the fast component of runoff response. This includes any surface runoff generated as infiltration excess runoff or saturation excess runoff (or the parameterized equivalent). In addition it should include any subsurface lateral quick-flow, which based on modelers experience is best routed as a fast storm-flow component, rather than a drainage or base-flow component. |
kg/m2s |
Out of gridcell |
Qsb |
Subsurface runoff |
This variable should include the slow drainage component of runoff response. This includes gravity drainage and slow response lateral flow. Ground water recharge will have the opposite sign. |
kg/m2s |
Out of gridcell |
Qrec | Recharge to the flood plain | Recharge from river to the flood plain. This variable represents streamflow which leaves the channel network and returns to the grid cell interface. The sign will always be opposite to that of surface runoff and the recharge quantity should not be subtracted from the surface runoff variable when recharge is specified. | kg/m2s | Into gridcell |
SoilMoist |
Soil moisture |
Soil water content in total soil layer (not one for each soil layer). Includes the liquid, vapor and solid phases of water in the soil. |
kg/m2 |
- |
RootMoist |
Root zone soil moisture |
Total simulated soil moisture available for evapotranspiration. "Available water" means that frozen water should not be included, and water below wilting point should also be excluded. |
kg/m2 |
- |
RootSoilStress |
Root zone soil stress |
RootMoist / (Critical soil moisture – Wilting point). Remember that RootMoist does not include frozen water or water below wilting point. Upper/lower limits should be set at 1/0. |
- |
- |
SWE |
Snow water equivalent |
Total water mass of the snowpack (liquid or frozen), averaged over a grid cell. |
kg/m2 |
- |
SnowFrac |
Snow covered fraction |
Grid cell snow covered fraction |
- |
- |
Dis |
Simulated river discharge |
Simulated river discharge |
m3/s |
- |
ECanop |
Interception evaporation |
Evaporation from canopy interception, averaged over all vegetation types within a grid cell. |
kg/m2s |
Upward |
TVeg |
Vegetation transpiration |
Transpiration from canopy, averaged over all vegetation types within a grid cell |
kg/m2s |
Upward |
ESoil |
Bare soil evaporation |
Evaporation from bare soil |
kg/m2s |
Upward |
EWater |
Open water evaporation |
Evaporation from surface water storage |
kg/m2s |
Upward |
ESSNow |
Snow evaporation and sublimation |
Total sublimation and evaporation from the snow pack, i.e. we ask for the sum of the standard ALMA EvapSnow and SubSnow, (ESSNow = EvapSnow + SubSnow). |
kg/m2s |
Upward |
SurfStor |
Surface water storage |
Total liquid water storage, other than soil, snow or interception storage (i.e. lakes, river channel or depression storage). |
kg/m2 |
- |
GroundMoist |
Groundwater |
Total ground water content. This variable is not included in the ALMA convention. |
kg/m2 |
- |
PotEvap |
Potential evapotranspiration |
The flux as computed for evapotranspiration but with all resistances set to zero, except the aerodynamic resistance. |
kg/m2s |
Upward |
Qst |
Snow throughfall |
Liquid water flowing out of the snow pack, meaning water (melted snow and/or rain) percolating through the snowpack. |
kg/m2s |
- |
Albedo |
Surface albedo |
Grid cell average albedo for all wavelengths |
- |
- |
SAlbedo |
Snow albedo |
Albedo of the snow-covered surface, averaged over the grid cell |
- |
- |
WaterTableD |
Water table depth |
Depth of the water table |
m |
- |
SWnet |
Net shortwave radiation |
Incoming solar radiation less the simulated outgoing shortwave radiation, averaged over a grid cell |
W/m2
|
Downward |
LWnet |
Net longwave radiation |
Incident longwave radiation less the simulated outgoing longwave radiation, averaged over a grid cell |
W/m2 |
Downward |
Qle |
Latent heat |
Energy of evaporation, averaged over a grid cell |
W/m2 |
Upward |
Qh |
Sensible heat |
Sensible energy, averaged over a grid cell |
W/m2 |
Upward |
Qg |
Ground heat |
Heat flux into the ground, averaged over a grid cell |
W/m2 |
Downward |
Table 2: Convention for model output data, water use terms. Be aware that this list may include more variables than should be submitted. See "Modelling Protocol" for the list of variables that should be submitted for your modelling purpose.
Variable | Description |
Definition |
Units |
PIrrUse | Potential irrigation water use |
Potential irrigation water use (water consumed), averaged over a gridcell |
kg/m2s |
PIrrWW |
Potential irrigation water withdrawn, averaged over a grid cell |
kg/m2s | |
PEConv | Potential irrigation conveyance losses | Potential irrigation conveyance losses, averaged over a grid cell |
kg/m2s |
PReturnFlow | Potential irrigation return flow | Potential irrigation return flow, averaged over a gridcell |
kg/m2s |
AIrrUse |
Actual irrigation water use (water consumed), averaged over a grid cell |
kg/m2s | |
AIrrWW | Actual irrigation water withdrawn, averaged over a grid cell |
kg/m2s | |
AEConv | Actual irrigation conveyance losses | Actual irrigation conveyance losees, averaged over a grid cell | kg/m2s |
AReturnFlow | Actual irrigation return flow | Actual irrigation return flow, averaged over a grid cell |
kg/m2s |
ADomWW |
Actual domestic water withdrawals |
Actual domestic water withdrawn, averaged over a grid cell |
kg/m2s |
ADomUse | Actual domestic water use |
Actual domestic water consumed, averaged over a grid cell |
kg/m2s |
AManWW |
Actual manufacturing water withdrawals |
Actual water withdrawn for manufacturing, averaged over a grid cell |
kg/m2s |
AManUse |
Actual manufacturing water use |
Actual water consumed, manufacturing, averaged over a grid cell |
kg/m2s |
AElecWW |
Actual electricity water withdrawals |
Actual water withdrawn for electricity production, averaged over a grid cell |
kg/m2s |
AElecUse | Actual electricity water use |
Actual water consumed, electricity production, averaged over a grid cell |
kg/m2s |
ALiveWW |
Actual livestock water withdrawals |
Actual water withdrawn for livestock farming, averaged over a grid cell |
kg/m2s |
ALiveUse |
Actual livestock water use |
Actual water consumed, livestock farming, averaged over a grid cell |
kg/m2s |
ResStor | Reservoir storage |
|
m3 |
ResRel | Reservoir release |
m3/s |
Table 3: Convention for model output data, blue/green water terms. This list is for those submitting results for the blue/green water initiative. If you do not know what the blue/green water initiative is, you can ignore this Table, or, if you are interested, contact Jens Heinke and/or Holger Hoff (see Contacts information).
Variable | Description |
Definition |
Units |
IrrigCropUseGreen |
Green water use (water consumed) on irrigated cropland |
Sum of evaporative fluxes (TVeg + ECanop + ESoil) from rain water over irrigated cropland, averaged over a grid cell. Fallow period should also be included. |
kg/m2s |
RainfCropUseGreen |
Green water use (water consumed) on rainfed cropland |
Sum of evaporative fluxes (TVeg + ECanop + ESoil) from rain water over rainfed (non-irrigated) cropland , averaged over a grid cell. Fallow period should also be included. |
kg/m2s |
PastureUseGreen |
Green water use (water consumed) on pasture |
Sum of evaporative fluxes (TVeg + ECanop + ESoil) from rain water over pasture, averaged over a grid cell. |
kg/m2s |