SUMMA Input Files

SUMMA has a large number of input files that configure the model and provide the necessary initial conditions and time-varying boundary conditions to make a model simulation. This can at times be confusing. We encourage the user to look at the SUMMA test cases, which provide working SUMMA setups.

Input file formats

SUMMA input files are either ASCII format or NetCDF. The general characteristics of these files are described in the next two subsections, while the contents of the individual input files are described after that.

ASCII

ASCII or text files are in a format that can be modified using a text editor. Comments can be added to any SUMMA text file by starting the comments with a !. Anything after the ! will be discarded till the end of the line. You can include as many comments as you want, as they will be stripped as SUMMA processes the file.

NetCDF

NetCDF or Network Common Data Format is a file format that is widely used in geosciences to organize large data sets. The main advantages of using NetCDF files is that they are machine independent, they allow the user to include meta data directly in the data file, and they can be read by, visualized and analyzed using a large number of freely available software packages. The SUMMA documentation is not the place to learn about NetCDF. We assume that you know the difference between NetCDF dimensions, NetCDF variables, and NetCDF attributes (global and local). If you don't, then there are many tutorials available online. Note that NetCDF attributes are different from the local SUMMA attributes that we are describing below.

SUMMA input files in NetCDF format can include variables (and dimensions) other than those specified below. They will simply not be read by SUMMA, but may be useful to facilitate further analysis and/or visualization. For example, it may be convenient to include latitude and longitude in many of the spatial files to allow visualization.

Master configuration file

The master configuration file is an ASCII file and is provided to SUMMA at run-time as a command-line option. The path to this file needs to be supplied with the -m or --master command-line flag. The contents of this file orchestrate the remainder of the SUMMA run and are processed by the code in build/source/hookup/summaFileManager.f90. The file contents mostly consist of file paths that provide the actual information about the model configuration.

The following items must be provided in order in the master configuration file. Each item must be on its own line, but may be followed by a comment and you can add lines of comments between the items. Each entry must be enclosed in single quotes 'entry'. In the following, I start each enumerated entry with the actual variable name that is used in the SUMMA source code to refer to each of the entries (in summaFileManager.f90) and its default value in case you are trying to trace a problem.

  1. summaFileManagerHeader: Version of the file manager that should be used to process the master configuration file. At this time, this string should be equal to 'SUMMA_FILE_MANAGER_V1.0'.

  2. SETNGS_PATH: Base path for the configuration files. Most of the file paths in the remainder of the master configuration file are relative to this path (except INPUT_PATH and OUTPUT_PATH).

  3. INPUT_PATH: Base path for the meteorological forcing files specified in the FORCING_FILELIST.

  4. OUTPUT_PATH: Base path for the SUMMA output files.

  5. M_DECISIONS: File path for the model decisions file (relative to SETNGS_PATH).

  6. META_TIME: No longer used as of SUMMA 2.x - simply specify 'N/A'.

  7. META_ATTR: No longer used as of SUMMA 2.x - simply specify 'N/A'.

  8. META_TYPE: No longer used as of SUMMA 2.x - simply specify 'N/A'.

  9. META_FORCE: No longer used as of SUMMA 2.x - simply specify 'N/A'.

  10. META_LOCALPARAM: No longer used as of SUMMA 2.x - simply specify 'N/A'.

  11. OUTPUT_CONTROL: File path for the output control file (relative to SETNGS_PATH).

  12. META_LOCALINDEX: No longer used as of SUMMA 2.x - simply specify 'N/A'.

  13. META_BASINPARAM: No longer used as of SUMMA 2.x - simply specify 'N/A'.

  14. META_BASINMVAR: No longer used as of SUMMA 2.x - simply specify 'N/A'.

  15. LOCAL_ATTRIBUTES: File path for the local attributes file (relative to SETNGS_PATH).

  16. LOCALPARAM_INFO: File path for the local parameters file (relative to SETNGS_PATH).

  17. BASINPARAM_INFO: File path for the basin parameters file (relative to SETNGS_PATH).

  18. FORCING_FILELIST: File path for the list of forcing files file (relative to SETNGS_PATH).

  19. MODEL_INITCOND: File path for the initial conditions file (relative to SETNGS_PATH).

  20. PARAMETER_TRIAL: File path for the trial parameters file (relative to SETNGS_PATH).

  21. OUTPUT_PREFIX: Text string prepended to each output filename to identify a specific model setup. Note that the user can further modify the output file name at run-time by using the -s|--suffix command-line option.

Model decisions file

The model decisions file is an ASCII file that indicates the model decisions with which SUMMA is configured. The model decisions file is parsed by build/source/engine/mDecisions.f90, which also serves as the file of record for all available options for the individual model decisions. The names for the model decisions are found in build/source/dshare/get_ixname.f90:function get_ixdecisions(varName). Detailed information about the individual model decisions and their associated options can be found in the configuration section.

Model decisions can be specified in any order with one decision per line. The decisions take the form <keyword> <value>, where <keyword> is the decision to be made and <value> is the option that is selected for that decision. For example, the line f_Richards mixdform indicates that the mixed form of the Richards's equation (unsaturated/saturated flow) should be used in the simulation(mixdform option for the f_Richards decision). Another option for this model decision would be moisture, which would be the moisture-based form (only unsaturated flow).

The model decisions file must also contain the start (simulStart) and end (simulFinsh) times of the simulation. These are specified as 'YYYY-MM-DD hh:mm' and must be enclosed in single quotes. They are typically the first model decisions to be specified.

The model decisions and their options or values are listed in the following tables. Note that the decisions and their options are case sensitive. For details about each option see the configuration section.

Decision option/value notes
simulStart 'YYYY-MM-DD hh:mm' ( 1) simulation start time
simulFinsh 'YYYY-MM-DD hh:mm' ( 2) simulation end time
soilCatTbl STAS
STAS-RUC
ROSETTA
( 3) soil-category dataset
vegeParTbl USGS MODIFIED_IGBP_MODIS_NOAH ( 4) vegetation category dataset
soilStress NoahType
CLM_Type
SiB_Type
( 5) choice of function for the soil moisture control on stomatal resistance
stomResist BallBerry
Jarvis
simpleResistance
BallBerryFlex
BallBerryTest
( 6) choice of function for stomatal resistance
bbTempFunc q10Func
Arrhenius
( 7) Ball-Berry: leaf temperature controls on photosynthesis + stomatal resistance
bbHumdFunc humidLeafSurface
scaledHyperbolic
( 8) Ball-Berry: humidity controls on stomatal resistance
bbElecFunc linear
linearJmax
quadraticJmax
( 9) Ball-Berry: dependence of photosynthesis on PAR
bbCO2point origBWB
Leuning
(10) Ball-Berry: use of CO2 compensation point to calculate stomatal resistance
bbNumerics NoahMPsolution
newtonRaphson
(11) Ball-Berry: iterative numerical solution method
bbAssimFnc colimitation
minFunc
(12) Ball-Berry: controls on carbon assimilation
bbCanIntg8 constantScaling
laiScaling
(13) Ball-Berry: scaling of photosynthesis from the leaf to the canopy
num_method itertive
non_iter
itersurf
(14) choice of numerical method
fDerivMeth numericl
analytic
(15) choice of method to calculate flux derivatives
LAI_method monTable
specified
(16) choice of method to determine LAI and SAI
cIntercept sparseCanopy
storageFunc
notPopulatedYet
(17) choice of parameterization for canopy interception
f_Richards moisture
mixdform
(18) form of Richards' equation
groundwatr qTopmodl
bigBuckt
noXplict
(19) choice of groundwater parameterization
hc_profile constant
pow_prof
(20) choice of hydraulic conductivity profile
bcUpprTdyn presTemp
nrg_flux
zeroFlux
(21) type of upper boundary condition for thermodynamics
bcLowrTdyn presTemp
zeroFlux
(22) type of lower boundary condition for thermodynamics
bcUpprSoiH presHead
liq_flux
(23) type of upper boundary condition for soil hydrology
bcLowrSoiH presHead
bottmPsi
drainage
zeroFlux
(24) type of lower boundary condition for soil hydrology
veg_traits Raupach_BLM1994
CM_QJRMS1998
vegTypeTable
(25) choice of parameterization for vegetation roughness length and displacement height
rootProfil powerLaw
doubleExp
(26) choice of parameterization for the rooting profile
canopyEmis simplExp
difTrans
(27) choice of parameterization for canopy emissivity
snowIncept stickySnow
lightSnow
(28) choice of parameterization for snow interception
windPrfile exponential
logBelowCanopy
(29) choice of canopy wind profile
astability standard
louisinv
mahrtexp
(30) choice of stability function
compaction consettl
anderson
(31) choice of compaction routine
snowLayers jrdn1991
CLM_2010
(32) choice of method to combine and sub-divide snow layers
thCondSnow tyen1965
melr1977
jrdn1991
smnv2000
(33) choice of thermal conductivity representation for snow
thCondSoil funcSoilWet
mixConstit
hanssonVZJ
(34) choice of thermal conductivity representation for soil
canopySrad noah_mp
CLM_2stream
UEB_2stream
NL_scatter
BeersLaw
(35) choice of method for canopy shortwave radiation
alb_method conDecay
varDecay
(36) choice of albedo representation
spatial_gw localColumn
singleBasin
(37) choice of method for spatial representation of groundwater
subRouting timeDlay
qInstant
(38) choice of method for sub-grid routing
snowDenNew hedAndPom
anderson
pahaut_76
constDens
(39) choice of method for new snow density

The model decisions for each simulation are included as global attributes in SUMMA output files.

Output control file

The output control file is an ASCII file that specifies which variables are retained in the SUMMA output files. The output control file is parsed by build/source/dshare/popMetadat.f90:read_output_file()

SUMMA is pretty flexible in its output. There are many variables that you can output and for most of them you can also choose to record summary statistics. For example, you can configure the model to run with meteorological forcings that are defined every hour, but only save summary output with a daily time step. This flexibility comes at the small price that you need to be clear in specifying what output you want.

The output control file includes a listing of model variables that you would like to store, with one model variable per line. The variables that are available for output are the individual entries in the data structures specified in build/source/dshare/var_lookup.f90. Because there are many, there is not much point in repeating them here, but we direct the user to the model code. Any of the variables specified in the following structures can be specified in the output control file: iLook_time, iLook_force, iLook_attr, iLook_type, iLook_param, iLook_index, iLook_prog, iLook_diag, iLook_flux, iLook_bpar, iLook_bvar, iLook_deriv. SUMMA will print an error message if a specific variable cannot be output, so the faster way may be to select any variable in build/source/dshare/var_lookup.f90 and remove it if it is not available for output. In addition, some of the variables may only be useful for debugging use, but that is up to the user.

At a minimum, each line in the output control file will contain two fields, separated by a |. The first field will be the variable name as specified in build/source/dshare/var_lookup.f90 (case-sensitive). The second field will be the frequency of the model output specified as a multiple of the time resolution in the model forcing files. Thus, if you want to output data for every forcing time step, then this value should be equal to 1. If you want daily output and your forcing frequency is 3 hours, then this value should be equal to 8. Note that you can specify different output frequencies for separate variables, but at this time you can specify only a single output frequency for each variable. For example, you can store scalarSenHeatTotal with an output frequency of 1 and scalarLatHeatTotal with an output frequency of 8, but you cannot specify two different output frequencies for scalarSenHeatTotal.

For most variables you can also output a statistical summary if you output variables at a lower frequency than your forcing frequency. To do this, you extend the number of fields you specify in the output control file, with all fields separated by a |. For the fields after the first two, you specify a series of 0's and 1's, which indicate that a specific statistic should not (0) or should be stored (1). The available statistics are (in order) the instantaneous value, the sum over the interval, the mean, the variance, the minimum, the maximum and the mode. So, a complete line in the output control file would be

! varName          | outFreq | inst | sum | mean | var | min | max | mode
scalarSenHeatTotal | 24      | 0    | 1   | 1    | 0   | 1   | 1   | 0

In this example, the first line is a comment (starts with !) and then the sum, mean, min, max are calculated for scalarSenHeatTotal across 24 forcing time steps and written to the output file.

List of forcing files file

The list of forcing files file is an ASCII file that specifies a list of meteorological forcing files that are read by SUMMA and that provide the time-varying atmospheric boundary conditions. The list of forcing files file contains one field per line, which specifies the name of a forcing file in single quotes. The file is parsed by build/source/engine/ffile_info.f90:ffile_info(). Each of the forcing files must contain all the GRUs/HRUs that are part of the simulation, but can contain a subset of the modeling period. For example, the forcing files can be organized by year or month to stop file sizes for large domains from becoming too unwieldy. In the forcing files file, these meteorological forcing files would be listed in order, with the earliest file listed first.

Meteorological forcing files

The meteorological forcing files are NetCDF files that specify the time-varying atmospheric boundary conditions for SUMMA. The files are parsed by build/source/engine/ffile_info.f90:ffile_info() to perform a series of file checks (number of HRUs, presence of all required variables) and by build/source/engine/read_force.f90:read_force() to get the meteorological information for the next time step.

Each forcing file must contain a time and a hru dimension. In addition, the file must contain the following variables at a minimum (it is OK if the file contains additional variables that will not be read, for example, it may be useful include latitude and longitude for each HRU to facilitate visualization of the forcing data)

Variable dimension type units long name notes
data_step - double seconds Length of time step Single value that must be the same for all forcing files in the same list of forcing files file
hruId hru int or int64 - Index of hydrological response unit (HRU) Unique numeric ID for each HRU
time time double see below time since time reference Time stamps are period-ending
pptrate time, hru double kg m-2 s-1 Precipitation rate
SWRadAtm time, hru double W m-2 Downward shortwave radiation at the upper boundary
LWRadAtm time, hru double W m-2 Downward longwave radiation at the upper boundary
airtemp time, hru double K Air temperature at the measurement height
windspd time, hru double m s-1 Wind speed at the measurement height
airpres time, hru double Pa Air pressure at the the measurement height
spechum time, hru double g g-1 Specific humidity at the measurement height

Notes about forcing file format:

  • Forcing timestep units: The user can specify the time units as <units> since <reference time>, where <units> is one of seconds, hours, or days and <reference time> is specified as YYYY-MM-DD hh:mm.

  • Forcing time stamp: SUMMA forcing time stamps are period-ending and the forcing information reflects average conditions over the time interval of length data_step preceding the time stamp.

  • Upper boundary: The upper boundary refers to the upper boundary of the SUMMA domain, so this would be at some height above the canopy or ground (in case there is no canopy).

  • Measurement height: The measurement height is the height (above bare ground) where the meteorological variables are specified. This value is specified as mHeight in the local attributes file.

SUMMA uses adaptive time stepping to solve the model equations. Atmospheric conditions are kept constant during the adaptive sub-steps that occur during a meteorological forcing time step.

Initial conditions, restart or state file

The initial conditions, restart, or state file is a NetCDF file that specifies the model states at the start of the model simulation. This file is required. You will need to generate one before you run the model for the first time, but after that the model restart file can be the result from an earlier model simulation. The file is written by build/source/netcdf/modelwrite.f90:writeRestart() and read by build/source/netcdf/read_icond.f90:read_icond_nlayers() (number of snow and soil layers) and build/source/netcdf/read_icond.f90:read_icond() (actual model states).

The frequency with which SUMMA writes restart files is specified on the command-line with the -r or --restart flag. This flag currently can be either y or year, m or month, d or day, or n or never.

As an input file, the variables that need to be specified in the restart file are a subset of those listed as iLook_prog in the var_lookup module in build/source/dshare/var_lookup.f90 (look for the comment (6) define model prognostic (state) variables). Variable names must match the code exactly (case-sensitive). Note that not all the variables in iLook_prog need to be specified, since some of them can be calculated from other variables. For example, SUMMA calculates mLayerHeight from iLayerHeight and the variable does not need to be reported separately. For similar reasons, the user does not need to specify scalarCanopyWat, spectralSnowAlbedoDiffuse, scalarSurfaceTemp, mLayerVolFracWat, and mLayerHeight since these are skipped when the file is read and calculated internally to ensure consistency. In addition to these variables, the restart file also needs to specify the number of soil and snow layers (nSoil and nSnow, respectively).

The restart file does not have a time dimension, since it represents a specific moment in time. However, it has the following dimensions,: hru, scalarv, spectral, ifcSoil, ifcToto, midSoil, and midToto. These dimensions are described in detail in the section on SUMMA output file dimensions (keep in mind that the restart files are both input and output).

Variable dimension type units long name notes
dt_init scalarv, hru double seconds Length of initial time sub-step at start of next time interval (s)
nSoil scalarv, hru int - Number of soil layers
nSnow scalarv, hru int - Number of snow layers
scalarCanopyIce scalarv, hru double kg m-2 Mass of ice on the vegetation canopy
scalarCanopyLiq scalarv, hru double kg m-2 Mass of liquid water on the vegetation canopy
scalarCanairTemp scalarv, hru double Pa Temperature of the canopy air space
scalarCanopyTemp scalarv, hru double K Temperature of the vegetation canopy
scalarSnowAlbedo scalarv, hru double - Snow albedo for the entire spectral band
scalarSnowDepth scalarv, hru double m Total snow depth
scalarSWE scalarv, hru double kg m-2 Snow water equivalent
scalarSfcMeltPond scalarv, hru double kg m-2 Ponded water caused by melt of the "snow without a layer"
scalarAquiferStorage scalarv, hru double m Relative aquifer storage -- above bottom of the soil profile
iLayerHeight ifcToto, hru double m Height of the layer interface; top of soil = 0
mLayerDepth midToto, hru double m Depth of each layer
layer
mLayerTemp midToto, hru double K Temperature of each layer
mLayerVolFracIce midToto, hru double - Volumetric fraction of ice in each layer
mLayerVolFracLiq midToto, hru double - Volumetric fraction of liquid water in each layer
mLayerMatricHead midSoil, hru double m Matric head of water in the soil

Attribute and parameter files

SUMMA uses a number of files to specify model attributes and parameters. Although SUMMA's distinction between attributes and parameters is somewhat arbitrary, attributes generally describe characteristics of the model domain that are time-invariant during the simulation, such as GRU and HRU identifiers, spatial organization, an topography. The important part for understanding the organization of the SUMMA input files is that the values specified in the local attributes file do not overlap with those in the various parameter files. Thus, these values do not overwrite any attributes specified elsewhere. In contrast, the various parameter file are read in sequence (as explained in the next paragraph) and parameter values that are read in from the input files successively overwrite values that have been specified earlier.

The figure below shows the order in which SUMMA processes the various attribute and parameter files. First, the local attributes file is processed, which provides information about the organization of the GRUs and HRUs as well as some other information. Then, SUMMA parses the local parameters file, which provides spatially constant values for all SUMMA parameters that need to be specified at the HRU level. SUMMA then parses the basin parameters file, which provides spatially constant values for all SUMMA parameters that need to be specified at the GRU level. In this case, it does not really matter which files is parsed first. The information in these two files does not overlap. At this point in SUMMA's initialization, all GRU and HRU parameters have been initialized to spatially constant values. SUMMA has inherited some routines from the NOAH land surface model and the next step is to parse the NOAH parameter tables, based on the spatial information specified in the local attributes file file. The information in these tables is used to overwrite the spatially constant values that have already been initialized for each HRU. Finally, the trial parameters file is parsed to provide additional GRU and HRU specific information. The values from this file will overwrite existing values. The number of variables specified in the trial parameters file will vary with the amount of location-specific information that you have available for your simulation.

Order in which SUMMA model attributes and parameters are specified and processed Order in which SUMMA model attributes and parameters are specified and processed.

Local attributes file

The local attributes file is a NetCDF file that specifies model element attributes for GRUs and individual HRUs. The local attributes file is parsed by build/source/driver/multi_driver.f90 and build/source/engine/read_attrb.f90. As described above, the attributes specified in this file are separate from the values specified in the various parameter files.

The local attributes file contains a gru and an hru dimension as specified in the table below. All variables in the local attributes file must be specified.

Variable dimension type units long name notes
hruId hru int - Index of hydrological response unit (HRU) Unique numeric ID for each HRU
gruId gru int - Index of grouped response unit (GRU) Unique numeric ID for each GRU
hru2gruId hru int - Index of GRU to which the HRU belongs gruId of the GRU to which the HRU belongs
downHRUindex hru int - Index of downslope HRU (0 = basin outlet) Downslope HRU must be within the same GRU. If the value is 0, then there is no exchange to a neighboring HRU. Setting this value to 0 for all HRUs emulates a series of independent columns
longitude hru double Decimal degree east Longitude of HRU's centroid West is negative or greater than 180
latitude hru double Decimal degree north Latitude of HRU's centroid South is negative
elevation hru double m Elevation of HRU's centroid
HRUarea hru double m^2 Area of HRU
tan_slope hru double m m-1 Average tangent slope of HRU
contourLength hru double m Contour length of HRU Width of a hillslope (m) parallel to a stream. Used in groundwatr.f90
slopeTypeIndex hru int - Index defining slope
soilTypeIndex hru int - Index defining soil type
vegTypeIndex hru int - Index defining vegetation type
mHeight hru double m Measurement height above bare ground

Below is a sample layout of the local attributes file (the output of running ncdump -h). In this case, both the gru and hru dimension are of size 1 (the example is taken from one of the test cases, most of which are point model simulations), but of course there can be many GRUs and HRUs.

netcdf sample_local_attributes_file_layout {
dimensions:
    hru = 1 ;
    gru = 1 ;
variables:
    int hruId(hru) ;
        hruId:long_name = "Index of hydrological response unit (HRU)" ;
        hruId:units = "-" ;
        hruId:v_type = "scalarv" ;
    int gruId(gru) ;
        gruId:long_name = "Index of grouped response unit (GRU)" ;
        gruId:units = "-" ;
        gruId:v_type = "scalarv" ;
    int hru2gruId(hru) ;
        hru2gruId:long_name = "Index of GRU to which the HRU belongs" ;
        hru2gruId:units = "-" ;
    int downHRUindex(hru) ;
        downHRUindex:long_name = "Index of downslope HRU (0 = basin outlet)" ;
        downHRUindex:units = "-" ;
    double longitude(hru) ;
        longitude:_FillValue = NaN ;
        longitude:long_name = "Longitude of HRU\'s centroid" ;
        longitude:units = "Decimal degree east" ;
    double latitude(hru) ;
        latitude:_FillValue = NaN ;
        latitude:long_name = "Latitude of HRU\'s centroid" ;
        latitude:units = "Decimal degree north" ;
    double elevation(hru) ;
        elevation:_FillValue = NaN ;
        elevation:long_name = "Elevation of HRU\'s centroid" ;
        elevation:units = "m" ;
    double HRUarea(hru) ;
        HRUarea:_FillValue = NaN ;
        HRUarea:long_name = "Area of HRU" ;
        HRUarea:units = "m^2" ;
    double tan_slope(hru) ;
        tan_slope:_FillValue = NaN ;
        tan_slope:long_name = "Average tangent slope of HRU" ;
        tan_slope:units = "m m-1" ;
    double contourLength(hru) ;
        contourLength:_FillValue = NaN ;
        contourLength:long_name = "Contour length of HRU" ;
        contourLength:units = "m" ;
    int slopeTypeIndex(hru) ;
        slopeTypeIndex:long_name = "Index defining slope" ;
        slopeTypeIndex:units = "-" ;
    int soilTypeIndex(hru) ;
        soilTypeIndex:long_name = "Index defining soil type" ;
        soilTypeIndex:units = "-" ;
    int vegTypeIndex(hru) ;
        vegTypeIndex:long_name = "Index defining vegetation type" ;
        vegTypeIndex:units = "-" ;
    double mHeight(hru) ;
        mHeight:_FillValue = NaN ;
        mHeight:long_name = "Measurement height above bare ground" ;
        mHeight:units = "m" ;
}

Local parameters file

The local parameters file is an ASCII file that specifies spatially constant parameter values for SUMMA parameters. The file is parsed by build/source/engine/read_pinit.f90:read_pinit().

The first non-comment line is a format string that is used to process the remaining non-comment lines. The format definition defines the format of the file, which can be changed. The format string itself is a Fortran format statement and must be in single quotes. For example,

'(a25,1x,3(a1,1x,f12.4,1x))' ! format string (must be in single quotes)

This states that the first field is 25 ASCII characters (a25), followed by a space (1x), and then 3 fields that each consist of an ASCII character (a1, the separator), followed by a space (1x), a float with 4 digits after the decimal (f12.4, note that you can also use this to read something like 1.0d+6), followed by another space (1x). For the separator we often use |, but other characters can be used as well. For example, this format statement can be used to read a line such as

upperBoundHead            |      -0.7500 |    -100.0000 |      -0.0100

All lines in the file (including the format statement) consist of four columns

  1. parameter name
  2. default parameter value
  3. lower parameter limit
  4. upper parameter limit

The parameters that need to be specified in this file are those listed as iLook_param in the var_lookup module in build/source/dshare/var_lookup.f90 (look for the comment (5) define model parameters). Parameter names must match the code exactly (case-sensitive). The parameter value is set to the default value (second column). The parameter value limits are currently not used, but still need to be specified. Our intention is to use them when reading the trial parameters file to ensure that the hru specific parameter values are within the specified limits.

Basin parameters file

The basin parameters file is an ASCII file that specifies spatially constant parameter values for SUMMA basin parameters. The file is parsed by build/source/engine/read_pinit.f90:read_pinit(). The format of the file is identical to that of the local parameters file.

The parameters that need to be specified in this file are those listed as iLook_bpar in the var_lookup module in build/source/dshare/var_lookup.f90 (look for the comment (11) define basin-average model parameters). Parameter names must match the code exactly (case-sensitive). The parameter value is set to the default value (second column). The parameter value limits are currently not used, but still need to be specified. Our intention is to use them when reading the trial parameters file to ensure that the gru specific parameter values are within the specified limits.

Noah-MP tables

SUMMA uses some of the input files and routines from the Noah-MP Land Surface Model (LSM). These routines are mostly contained in the build/source/noah-mp directory, although a few can be found elsewhere in the code as well. For example, the code that parses the Noah-MP tables is in build/source/driver/multi_driver.f90:SOIL_VEG_GEN_PARM(). The names of these tables is hard-wired (since that it is how this is implemented in Noah-MP). The file path for these tables is constructed as <SETNGS_PATH>/<NOAH_TABLE>, where SETNGS_PATH is defined in the master configuration file and NOAH_TABLE is VEGPARM.TBL, SOILPARM.TBL and GENPARM.TBL. The format for these files remains unchanged from their specification in Noah-MP, see here for an example. The parameter values in the Noah-MP overwrite the default values that have already been specified based on soil and vegetation type.

Trial parameters file

The trial parameters file is a NetCDF file that specifies model parameters for GRUs and individual HRUs. This enables the user to overwrite the default and/or Noah-MP parameter values with local-specific ones. The trial parameters file is parsed by build/source/engine/read_param.f90:read_param().

The trial parameters file contains a gru and/or an hru dimension, depending on whether GRU or HRU are being specified. The file can be used to overwrite any of the variables in the basin parameters file, in which the variable dimension should be gru, or in the local parameters file, in which the variable dimension should be hru. The file can contain zero or more parameter fields.

The file should include an index variable (hruId and/or gruId) that corresponds to the values used in the local attributes file to provide the mapping of parameter values to each individual HRU and GRU. Variable names in the trial parameters file must match those in build/source/dshare/var_lookup.f90:iLook_param for HRU parameters and build/source/dshare/var_lookup.f90:iLook_bpar for GRU parameters. Note that this matching is case-sensitive.