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MESH - A Community Hydrology - Land Surface Model


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Version 2.0 of MESH_parameters_hydrology.ini introduces several enhancements and improvements over older formats of the file. The file allows comments, adds names to identify parameters, and extends the channel routing parameter section. The file is labelled with the '2.0:' version number.

Overview

MESH_parameters_hydrology.ini contains four sections: option flags, channel routing parameters, hydrologic parameters that are not tied to any one GRU, and hydrologic parameters that are tied to specific GRUs.

Consult the Parameters Selection page for more information about specific parameters and recommended parameter values.

All lines in the file are read as space delimited. All fields should be separated by one or more spaces. However, the spacing of the fields and number of spaces taken by each field does not have to be consistent from one line to the next.

Page contents:

Sample File

MESH_parameters_hydrology.ini
2.0: MESH Hydrology parameters input file (Version 2.0)
##### Option Flags #####
----#
    0 # Number of option flags
##### Channel routing parameters #####
-------#
       1 # Number of channel routing parameters
WF_R2          0.842
##### GRU independent hydrologic parameters #####
-------#
       0 # Number of GRU independent hydrologic parameters
##### GRU dependent hydrologic parameters #####
-------#
       3 #Number of GRU dependent hydrologic parameters
ZSNL             0.1       0.1       0.1
ZPLS             0.1       0.1       0.1
ZPLG             0.1       0.1       0.1

File Structure

Comments

Lines that begin with '!' are prescribed comment lines, which are skipped when reading the file. These lines are not included when numbering the lines in the following sections.

MESH_parameters_hydrology.ini
!> Everything following the colon in the version string is ignored.

Field structure

Nearly all fields in the file use the same free format, whitespace delimited structure.

MESH_parameters_hydrology.ini

FIELD_NAME Value1 Value2 ... ValueN

Notes:

  • FIELD_NAME is not case-sensitive; FIELD_NAME, field_name, and FiEld_NaMe are equivalent
  • FIELD_NAME may be tied to a specific control flag, land surface scheme, or routing routine (see the tables in each section below)

There are constraints on the allowed total line length, field length, and number of fields. Exceeding these constraint can cause an instability when reading from the file.

Maximum line length500 characters
Maximum field length20 characters
Total number of delimited fields (including FIELD_NAME)50

Sections

Header information

The first line in the file must begin with "2.0:" followed by whitespace. Any comment before this line is ignored.

MESH_parameters_hydrology.ini
!> Lines that begin with '!' are skipped as comments.
!> The version string of the new format file is required: '2.0:'. The colon is required.
!> Everything following the colon in the version string is ignored.
2.0: MESH Hydrology parameters input file (Version 2.0)

Option flags

The first two lines are skipped, and then the number of option flags to read from the file is read. The text after this number is ignored.

MESH_parameters_hydrology.ini (excerpt)
##### Option Flags #####
----#
    0 # Number of option flags
!> There are no option flags recognized or active at present.

Each option flag is read as one additional line. No option flags/additional lines are read if this number is zero.

There are currently no option flags in use by the model. 

Channel routing parameters

This section includes the river roughness coefficients (WF_R2) included in previous versions of the file, but also other parameters to parameterize channel sinuosity and capacity, and new parameters for RTE.

The first two lines are skipped, and then the number of parameters to read from the file is read. The text after this number is ignored.

MESH_parameters_hydrology.ini (excerpt)
##### Channel routing parameters #####
-------#
       1 # Number of channel routing parameters
!> The number of [Value] should match the number of river classes from the drainage database.
!> NRVR      ----- 1
WF_R2          0.842

Each parameter is read as one additional line. No parameters/additional lines are read if this number is zero.

The line must begin with a field name from the tables below. Values are listed after the field name. For all channel routing parameters, the number of values expected is the number of river classes (NRVR) defined by IAK in MESH_drainage_database.r2c.

Certain parameters may be tied to and only enabled when running with a particular routing routine.

If all the grids in a domain have IAK=2, two values for these parameters are expected. However, because no grid has IAK=1, only the second value is used.

MESH_parameters_hydrology.ini (excerpt)

!> NRVR      ----- 1 ----- 2
WF_R2            0.0   0.842

Channel routing parameters (WF_ROUTE)

Field NameNo. of ValuesTypeDescriptionDefault ValueUnits
WF_R21->NRVRRealRiver channel roughness factor for channel routing, which incorporates a channel shape and width to depth ratio as well as Manning's n; typical values range from 0.3 to 1.0; a higher number corresponds to an increased river roughness; typically calibrated--s m-1/3
WF_R11->NRVRRealOverbank factor, applied to WF_R2 to determine the overbank roughness factor; WF_R1 in fact equals WF_R2*WF_R12.0--
WF_A11->NRVRRealMeander factor, applied to the channel length1.0--
WF_A21->NRVRRealBankfull/drainage area relationship intercept (i.e., min. cross-sectional area)11.0--
WF_A31->NRVRRealBankfull/drainage area relationship coefficient0.43--
WF_A41->NRVRRealBankfull/drainage area relationship exponent1.0--

Channel routing parameters (RTE)

Field NameNo. of ValuesTypeDescriptionDefault ValueUnits
R2N1->NRVRRealChannel Manning's n; typically calibrated--
R1N1->NRVRRealOverbank Manning's n; typically calibrated--
MNDR1->NRVRRealMeander factor, applied to the channel length1.0--
WIDEP1->NRVRRealChannel width to depth ratio10.0--
AA21->NRVRRealBankfull/drainage area relationship intercept (i.e., min. cross-sectional area)1.1--
AA31->NRVRRealBankfull/drainage area relationship coefficient0.043--
AA41->NRVRRealBankfull/drainage area relationship exponent1.0--

BASEFLOWFLAG wf_lzs

Field NameNo. of ValuesTypeDescriptionDefault ValueUnits
pwr1->NRVRReal

Exponent on the lower zone storage in the lower zone function; values may range from 2.0 to 3.0 when using an hourly time-step; typically calibrated

----
flz1->NRVRReal

Lower zone function; values may range from 1.0e-06 to 1.0e-04; typically calibrated

----

GRU-Independent hydrologic parameters

GRU-independent parameters are those that are not tied to any one GRU. A single value applies to the parameter across the entire domain.

The first two lines are skipped, and then the number of parameters to read from the file is read. The text after this number is ignored.

MESH_parameters_hydrology.ini (excerpt)
##### GRU independent hydrologic parameters #####
-------#
       5 # Number of GRU independent hydrologic parameters
SOIL_POR_MAX     0.8
SOIL_DEPTH     3.393
S0             0.962
T_ICE_LENS     -10.0
!> YEAR      ----- 1 ----- 2 ----- 3 ----- 4 ----- 5
t0_ACC        250.58  250.58  311.11  390.98  257.47

Each parameter is read as one additional line. No parameters/additional lines are read if this number is zero.

The line must begin with a field name from the tables below. Values are listed after the field name. The number of values expected is parameter-specific.

Certain parameters may be tied to and only enabled when running with a particular routing routine.

FROZENSOILINFILFLAG (only CLASS 3.6)


Field NameNo. of ValuesTypeDescriptionDefault ValueUnits
SOIL_POR_MAX1RealMaximum porosity of the soil----
SOIL_DEPTH1RealMaximum permeable depth of the soil (of the rooting zone)--m
S01RealMaximum saturation of the soil during melt; from 0.75-1.0--mm3 mm-3
T_ICE_LENS1RealMinimum temperature to allow formation of an ice sheet at the surface of the soil; from -50.0-0.0--deg C
t0_ACC1->n_yearsRealOpportunity time of infiltration into the frozen or freezing soil; set to 0.0 to allow the model to calculate this; a value is required for as many years as are simulated--hr

BASEFLOWFLAG luo_2012

Field NameNo. of ValuesTypeDescriptionDefault ValueUnits
WrchrgIni1RealInitial constant recharge for cold start--mm hr-1
QbIni1RealInitial constant baseflow for cold start--mm hr-1

BASEFLOWFLAG wf_lzs

Field NameNo. of ValuesTypeDescriptionDefault ValueUnits
WrchrgIni1RealInitial depth of storage in the lower zone0.0kg m-2 s-1
It's possible a future update will not re-purpose 'WrchrgIni', and that lower zone storage will have to be initialized using the 'lzs' variable explicitly.

GRU-Dependent hydrologic parameters

GRU-independent parameters are those that are parameterized by GRU.

The first two lines are skipped, and then the number of parameters to read from the file is read. The text after this number is ignored.

MESH_parameters_hydrology.ini (excerpt)
##### GRU dependent hydrologic parameters #####
-------#
       3 #Number of GRU dependent hydrologic parameters
!> The number of [Value] should match the number of GRUs from CLASS.ini.
!> GRU     ------- 1 ------- 2 ------- 3
ZSNL            0.58      0.58      0.58
ZPLS            0.48      0.48      0.48
ZPLG            0.46      0.46      0.46

Each parameter is read as one additional line. No parameters/additional lines are read if this number is zero.

The line must begin with a field name from the tables below. Values are listed after the field name. For all GRU-dependent parameters, the number of values expected is the number of GRUs (NM/NTYPE) defined in MESH_drainage_database.r2c (':ClassCount' - 1) and MESH_parameters_CLASS.ini.

The number of GRUs is no longer provided with this version of the file. When converting an old version of the file, the line should be commented or removed.
Certain parameters may be tied to and only enabled when running with a particular routing routine.

CLASS 3.6

Field NameNo. of ValuesTypeDescriptionDefault ValueUnits
ZSNL1->NTYPERealMinimum depth to consider 100% cover of snow on the ground surface--m
ZPLS1->NTYPERealMaximum depth of liquid water allowed to be stored on the ground surface for snow-covered areas--m
ZPLG1->NTYPERealMaximum depth of liquid water allowed to be stored on the ground surface for snow-free areas--m

IWF 2 and 3 – PDMROF/LATFLOW (only CLASS 3.6)

Field NameNo. of ValuesTypeDescriptionDefault ValueUnits
CMAX1->NTYPERealMaximum depth of storage (liquid water)--m
CMIN1->NTYPERealMinimum depth of storage (liquid water)--m
B1->NTYPERealShape factor----
K11->NTYPERealTime constant for the first linear reservoir--hr
K21->NTYPERealTime constant for the second linear reservoir--hr

FROZENSOILINFILFLAG (only CLASS 3.6)

Field NameNo. of ValuesTypeDescriptionDefault ValueUnits
FRZC1->NTYPERealCoefficient of the equation for the infiltration of meltwater into frozen or freezing soils; from 1-3----

PBSMFLAG (only CLASS 3.6)

Field NameNo. of ValuesTypeDescriptionDefault ValueUnits
fetch1->NTYPERealDistance of unobstructed wind flow; minimum 300.0--m
Ht1->NTYPERealVegetation height; a smaller values allows more erosion--m
N_S1->NTYPERealVegetation number density; typically 1.0-500.0; recommended 300.0 for crops and grass, 1.0 for forests and shrubs--count m-2
A_S1->NTYPERealVegetation diameter; typically 0.0-2.0; recommended 0.003 for crops and grass, 0.5-1.0 for forests and shrubs--m2
Distrib1->NTYPERealSnow distribution factor, controlling drift; set 0.0-1.0 for first GRU and >= 1.0 for the rest; recommended is to set GRU1=0.0 and all others =1.0, so that the remainder of the GRUs receive equal drift----

BASEFLOWFLAG luo_2012

Field NameNo. of ValuesTypeDescriptionDefault ValueUnits
dgwsh1->NTYPERealDelay time of the overlying soil layers in the  aquifer--hr
agwsh1->NTYPERealRecession constant of the aquifer----
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