WaterMIP Protocol 2009A

This round (2009A) of WaterMIP (Water Model Intercomparison Project) will be done both with and without major human impacts (e.g. dams, irrigation). If you for some reason want to see the protocol for the 2008 round, you can find it here.

Content


Spatial resolution and land mask
The spatial resolution for this model intercomparison is 0.5 degrees latitude by longitude, and the land areas of the globe (excluding Antarctica) should be covered. The grid cell midpoints should be located at .25 and .75 latitude/longitude. A standardized land mask (CRU) should be used by all models. The land mask can be found on the Watch ftp site (folder WorkBlock1, see README file).  

Model periods

The modelling period should be at least 20 years: The reporting period is 1985 – 1999, which should be preceded by at least 5 years (1980-1984) of spin-up.

 

Atmospheric forcings

The forcing data can be found on the Watch ftp site at IIASA (folder WorkBlock1 - WATCH Forcing Data, see README file for information). The main variables are in 6-hourly or 3-hourly time steps, and at daily time step. NB! For rainf and snowf use the GPCC versions!!! The WFD_Interpolator fortran code is available from the ftp site in the Workblock1 folder under Watch_Forcing_Data/WFD_code. The main use of the WFD_Interpolator will be to, for example, convert the 6-hourly WFD variables (Tair, Wind, Qair, PSurf and LWdown) to 3-hourly so that, together with the 3-hourly WFD variables (SWdown Rainf and Snowf), land surface- and hydrological models can be run with a diurnal cycle.

 

Elevation, land use/cover, soil information

Each model will use their “own” elevation, land use/cover and soil information. Land use/cover information, especially LAI data, should be reported when submitting the data. For those using elevation information, we recommend using CRU elevations, which can be found on the Watch ftp site (folder WorkBlock1). Also remember that The Harmonized World Soil Database, a 30 arc-second raster database, is newly released.  

Routing network
The provided DDM30 routing network (see Watch WaterMIP ftp site at IIASA), which is mapped to the CRU land mask, should be used by all modelling groups. The network includes flow direction, slope, and basin numbers, and is available on the Watch WaterMIP ftp site. The routing network includes large lakes not included in the provided land mask. These cells should not be included when results are submitted, though, and there should be no runoff added to the river network from these cells. I.e. these cells are included only for transportation purposes (streamflow).  

Human impacts

This round (2009A) of intercomparisons will be done both with and without major human impacts. For the human impact rounds, we will now only take dams and irrigation into account, since most models do not include other water uses. For those interested, the global land and wetlands database (GLWD1), which also includes information on reservoirs, can be found on our WaterMIP ftp site.  

 

Data format and data convention, file array structure and variable naming convention

See menu "Data Format" for general information. Some additional information specific to WaterMIP can be found in paragraph "File naming convention and array structure" below.

 

Requested variables: WaterMIP 2009A 

All the requested output variables (see Tables 1 and 2) should be submitted as fields (gridded values) of monthly means for each simulation run (15 years of 12 monthly values, in total 180 values for each grid cell and output variable) for land points and ocean points from -56 to 84 degrees latitude, and from -180 to 180 degrees longitude, i.e. 280 rows and 720 cols, or 201600 grid cells totally. Ocean points should be included because it makes visualizing the netCDF files easier. The variable names and units are to follow the ALMA protocol (http://www.lmd.jussieu.fr/~polcher/ALMA). Please submit as many variables as possible!

In addition, gridded fields of daily values should be submitted for some water balance variables for the period 1987-1988, see also Table 1.

Gridded fields of water state variables (SWE, SoilMoist, GroundMoist, SurfStor, others if applicable) at the beginning and end of the 15-year reporting period should also be submitted, so that long-term water balance can be calculated as follows:

Precip = Qs + Qsb + Evap + Δ(SWE, SoilMoist, GroundMoist, SurfStor) 

The modellers should also submit a field with the long-term vertical water balance at the grid cell level, followed by a description of which variables are taken into account when calculating the water balance. Note that we do not ask for state variables at the beginning and end of the reporting period for the daily fields.

Table 1: Requested model output variables (see menu "Data format" for a more precise definition of the variables. Origin:  http://www.lmd.jussieu.fr/~polcher/ALMA). Please submit as many variables as possible!

 Variable  Description  Monthly (1985-1999)  Daily (1987-1988) 
 Precip  Precipitation rate

 X

  
 Snowf  Snowfall

 X

 X

 Evap  Total evapotranspiration

 X

 X

 Qs  Surface runoff

 X

 X

 Qsb  Subsurface runoff

 X

 X

 SoilMoist  Soil moisture

 X

 X

 RootMoist  Root zone soil moisture

 X

  
 RootSoilStress  Root zone soil stress

 X

  
 SWE  Snow water equivalent

 X

 X

 SnowFrac  Snow covered fraction

 X

  
 Dis  Simulated river discharge

 X

 X

 ECanop  Interception evaporation

 X

 

 TVeg  Vegetation transpiration

 X

 

 ESoil  Bare soil evaporation

 X

 

 EWater  Open water evaporation

 X

 

 ESSNow  Snow evaporation and sublimation

 X

 

 SurfStor  Surface water storage

 X

 X

 GroundMoist  Groundwater

 X

 X

 PotEvap  Potential evapotranspiration

 X

 X

 Qrec  Recharge to the flood plain

 X
 Qst  Snow throughfall

 X
 Albedo  Surface albedo

 X
 SAlbedo  Snow albedo

 X
 WaterTableD  Water table depth

 X
 SWnet  Net shortwave radiation

 X
 LWnet  Net longwave radiation

 X

For the human impact runs, we also request the variables listed in Table 2. The long-term irrigation water balance can be calculated as follows: 

IrrWW = IrrUse + EConv + ReturnFlow (here assuming that the long-term storage changes can be neglected).  

Table 2: Requested model output variables for the simulations with human impacts (in addition to those in Table 1). See also menu "Data format". Follow the links for additional information. 

 Variable  Description 

Monthly (1985-1999) 

 PIrrUse  Potential irrigation water use 

X

 PIrrWW  Potential irrigation water withdrawals

X

 PEConv  Potential irrigation conveyance losses

X

 PReturnFlow  Potential irrigation return flow

X

 AIrrUse  Actual irrigation water use

X

 AIrrWW  Actual irrigation water withdrawals

X

 AEConv  Actual irrigation conveyance losses

X

 AReturnFlow  Actual irrigation return flow

X

 ResStor  Reservoir storage

X

 ResRel  Reservoir release

X

 

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). See also menu "Data Format".

Variable Description  Temporal resolution    
IrrigCropUseGreen

Green water use (water consumed), cropland

 Preferrably monthly, but yearly is also OK

RainfCropUseGreen

Green water use (water consumed), cropland

 Preferrably monthly, but yearly is also OK
PastureUseGreen

Green water use (water consumed), pasture

 Preferrably monthly, but yearly is also OK

 

The blue-green water initiative is also asking for the following files:
  • CellArea: Area if grid cell in m2.
  • RainfCropFrac: Fraction of grid cell treated as rainfed cropland.
  • IrrigCropFrac: Fraction of grid cell treated as irrigated cropland.
  • PastureFrac: Fraction of grid cell treated as (rainfed) pasture.

 

 

File naming convention and array structure

One file should include only one variable when submitting the data. Use only lowercase letters in the file names, since some netCDF viewers only accept lowercase letters in their filenames. The submitted time series of monthly and daily data should use the following file naming convention, where setup refers to input forcings and model setup, and variablename refers to the variable names used in the ALMA convention: 

 

·      modelname_setup_variablename_monthly_1985_1999.nc, e.g.: 

      gwava_wfdnat_evap_monthly_1985_1999.nc (watch forcing data, naturalized simulations) and gwava_wfdhum_evap_monthly_1985_1999.nc (watch forcing data, simulations including human influences). 15 year of monthly data in one file.

·      modelname_setup_variablename_daily_yyyy.nc, e.g. gwava_wfdnat_evap_daily_1987.nc. Include only one year of data in one file.

 

The gridded fields of water state variables at the beginning and the end of the 15-year reporting period, in addition to gridded fields of LAI, soil depth and rooting depth, should follow the following file naming convention:

·          modelname_setup_statevariablename_ini.nc, e.g. gwava_wfdnat_soilmoist_ini.nc

·          modelname_setup_statevariablename_end.nc, e.g. gwava_wfdnat_soilmoist_end.nc

·          modelname_setup_vegorsoilparameter.nc, e.g. gwava_wfdnat_lai.nc

Use the ALMA convention for the state variable names (both in the file name and in the short field name)! Note that we do not ask for state variables at the beginning and end of the reporting period for the daily fields.

Data are to be submitted for the area -56 to 84 degrees latitude, and from -180 to 180 degrees longitude, i.e. 280 rows and 720 cols, or 201600 grid cells totally. Write the outputs row-wise starting at -55.75 and -179.75, and ending at 83.75 and 179.75.

 

Naming convention in netCDF:

  • x-dimension name: lon
  • x-dimension units: degrees_east
  • y-dimension name: lat
  • y-dimension units: degrees_north
  • t-dimension name: time
  • t-dimension units: months since 1985-01-01, i.e. numbered from 0 to 179, or days since 1987-01-01 / 1988-01-01 for the daily fields. Months should refer to calendar months, and not year/12 which is sometimes used.
  • missing_value: 1.e+20f

Example of naming of variables:

  • Long field name: Total evapotranspiration (Use the ALMA variable description)
  • Short field name: Evap (Use the ALMA variable names, also for the state files!)
  • Field units: kg/m2s (Use the ALMA variable units)

The size of one output file including one variable at monthly time steps for a 15 year period is about 138 MB (netcdf format, uncompressed). Zip-compressed the file size is less than 10 percent of the uncompressed file size. The size of one output file including one variable at daily time steps for a 1 year period is over 250 MB uncompressed.

  

Data submission
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.

 

The files should be uploaded to the Watch WaterMIP ftp server at IIASA! Put your results in the appropriate subfolder. Remember to zip the files!