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Input for MAP D-PHASE Implementation Plan
Section 4.1.3: Common format for hydrological model data
Authors: Simon Jaun & WG-DI members
Version 1.0 as of 19 April 2007
Naming convention for output files (case insensitive):
Naming convention for output files (case insensitive):
<INIDATE(10)>_<MODEL(8)>_<DRIVINGDATA(8)>_D.nc
where
– INIDATE:
YYYYMMDDHH (in UTC), initial time of the forecast
– MODEL:
hydrological model name (e.g., PREVAH)
– DRIVINGDATA:
– atmospheric model name (e.g., COSMOCH7) or
– GAUGES (hydrological input) or
– RADAR (atmospheric input, radar) or
– OBS (atmospheric input, conventional observations) or
– MIX (observed and modelled input)
– D stands for data.
Format definition:
The hydrological NetCDF file unifies data from all considered stations / catchments per
meteo data source. The meteo data source can be anything, models, observations,
radar ... (cf. naming convention). Every file only contains data from one model run (the
probabilistic ones contain one ensemble run, with eg. 16 members). The following
description is based on the example of a deterministic hydrological forecast driven by a
meteorological model (COSMOCH7) for 5 catchments.
Three variables are stored in hourly time steps:
– runoff (Runoff, from the hydrol. model)
– precip (Mean area precipitation, driving the hydrol. model)
– soilmoist (Soil moisture storage, from the hydrol. model)
The variables are depending on the station, the members of the driving model (only
one simulation in the deterministic case, several for probabilistic forecasts) and the
time:
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dimensions:
char_leng = 100 ;
(only used as helper-dimension for catchment descriptions)
station = 5 ;
(number of stations / catchments)
simulation = 1 ;
deterministic)
(number of ensemble members, here only 1 ->
time = UNLIMITED ; // (72 currently) (corresponds to the number of time steps
your specific simulation has)
The variable definitions for time are fairly self-explanatory (“float time”, the units can be
adjusted to your needs). The members (member_names) can be additionally weighted
(member_weight: -1 for deterministic runs, 1 for unweighted ensembles). The following
variables are descriptive attributes for each station / catchment:
– Station names
– River names
– Unique station number
– Station coordinates, latitude (WGS84)
– Station coordinates, longitude (WGS84)
– Station height, above sea level
– Catchment area, without upstream catchments
– Total catchment area, including upstream catchments
– Glaciation of the catchment, without upstream catchments
– Total glaciation of the catchment, including upstream catchments
– Max. soil moisture storage of the catchment, without upstream catchments
– Max. soil moisture storage of the catchment, including upstream catchments
Each of the descriptive station attributes generally also has a unit identifier (with
exception of the name attributes, cf. to the complete example file definition below). The
global attributes of the file finally show some general information, as the involved
institutions, the name of the hydrological model, etc. (cf. complete example file
definition).
To check out the provided NetCDF example file (cross.dkrz.de:/path/to/file.nc), use the
following commands:
ncdump -c file.nc (shows variables and attributes)
ncdump -v runoff file.nc (shows runoff data)
ncdump -v station_names file.nc (shows names of considered stations)
download: http://www.unidata.ucar.edu/software/netcdf/binaries.html
howto: http://badc.nerc.ac.uk/help/formats/netcdf/nc_utilities.html
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Example files:
DetHydro: 2007041800_prevah_cosmoch2_d.nc
ProbHydro: 2007041800_prevah_cleps_d.nc