Difference between revisions of "Project File:Continuous Simulations – Optional"

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| <pre>CFGI </pre> || ''none'' || || Use the CFGI model to simulate frozen soil effects.
 
| <pre>CFGI </pre> || ''none'' || || Use the CFGI model to simulate frozen soil effects.
 
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| <pre>CFGI_INDEX  </pre> || ''real'' || degree C days || Threshold value (degree C days) to differentiate between frozen and unfrozen soils. Default - 83.0.
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| <pre>CFGI_INDEX  </pre> || ''real'' || degree C hours|| Threshold value (negative degree C hours) to differentiate between frozen and unfrozen soils. Default: 83.0.
 
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| <pre>CFGI_K  </pre> || ''real'' || dimensionless || Snow thermal effect constant (K) in CFGI equation. Default - 0.5.
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| <pre>CFGI_K  </pre> || ''real'' || dimensionless || Snow thermal effect constant (K) in CFGI equation. Default: 0.5.
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| <pre>GTFSM</pre> || ''none'' || dimensionless || Use frozen soil hydraulic conductivity equation. If not used then assumed to be 0.
 
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Latest revision as of 19:24, 21 August 2024

Continuous simulations require general information about the watershed location, selection of a method to calculate evapo-transpiration (ET), hydrometeorological (HMET) data in one of three available formats, and the appropriate distributed data either from the Mapping Table file or from GRASS ASCII maps.

3.8.1 Required Inputs

Card Argument Units Description 
LONG_TERM
 none   Specifies continuous simulation. REQUIRES one of ET_CALC_PENMAN or ET_CALC_DEARDORFF.

REQUIRES one of three HMET formats. Also REQUIRES INF_REDIST or INF_RICHARDS. 

LATITUDE  ##.##
 real decimal
degrees 		Latitude of catchment centroid. 
LONGITUDE  ##.##
 real decimal
degrees 		Longitude of catchment centroid. 
GMT  ##.##
 real hr Number of hours difference between the time zone of the catchment and Greenwich Mean Time (e.g. –5 for EST). 
SOIL_MOIST_DEPTH  ##.##
 real m Depth of the active soil moisture layer from which ET occurs (m). 
EVENT_MIN_Q  ##.##
 real m3/s Threshold discharge for continuing runoff events. 
ET_CALC_PENMAN
 none none Calculate evapo-transpiration using the Penman-Monteith (1971) method. Select EITHER Penman or Deardorff. 
ET_CALC_DEARDORFF
 none none Calculate evapo-transpiration using the Deardorff method. Select EITHER Penman or Deardorff

3.8.2 Seasonal Canopy Resistance - Optional

Card Argument Units Description 
SEASONAL_RS
 none none Specifies that the values of canopy resistance vary seasonally 
SEASONAL_RS_SPRING
 integer month Optional card to specify the month that spring begins; canopy resistance will decrease linearly from a canopy resistance multiplication factor of 4.0 to 1.0 until the SEASONAL_RS_SUMMER_START month is reached. Default is 3 for latitudes below 37 degrees and 4 for latitudes above 37 degrees. 
SEASONAL_RS_SUMMER_START
 integer month Optional card to specify the month that begins the peak summer growing season, with a canopy resistance mulitplication factor of 1.0. Default is 5 for latitudes less than 37 and 7 for latitudes above 37. MUST be specified if SEASONAL_RS_SPRING card is included. 
SEASONAL_RS_SUMMER_END
 integer month Optional card to specify the month that ends the peak summer growing season, with a canopy resistance multiplication factor of 1.0. Default is 9. MUST be specified if SEASONAL_RS_SPRING card is included. 
SEASONAL_RS_FALL
 integer month Optional card to specify the month that begins the winter dormant period with a canopy resistance multiplication factor of 4.0. Default is 11. MUST be specified if SEASONAL_RS_SPRING card is included.
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3.8.3 Format of Hydrometeorological (HMET) Data – Required, Select One Format

Card Argument Description 
HMET_SURFAWAYS  "filename.hmt"
 file name ASCII file with hourly HMET data formatted in the form of the NOAA/NCDC Surface Airways Data. Mutually exclusive with HMET_SAMSON and HMET_WES; one required for LONG_TERM. 
HMET_SAMSON  "filename.hmt"
 file name ASCII file with hourly HMET data formatted as per the NOAA/NCDC SAMSON CD-ROM data set. Mutually exclusive with HMET_WES and HMET_SURFAWAYS; one required for LONG_TERM. 
HMET_WES  "filename.hmt"
 file name ASCII file with hourly HMET data written using a simple format discussed in the Continuous Simulation Section of this document. Mutually exclusive with HMET_SURFAWAYS and HMET_SAMSON; one required for LONG_TERM.


3.8.4 ET Parameter Assignment – Required, Select Mapping Table or GRASS ASCII maps

Long-term simulation parameters must be assigned using either the Mapping Table or providing the GRASS ASCII maps as described below. Albedo, wilting point, transmission coefficient, vegetation height and canopy resistance are also required for ET_CALC_PENMAN.

Card Argument Description 
ALBEDO  "filename.alb"
 map name Name of GRASS ASCII map containing short-wave albedo values (0.0 – 1.0). 
WILTING_POINT  "filename.wtp"
 map name Name of GRASS ASCII map containing values of the wilting point volumetric water content (0.0 - 1.0). 
TCOEFF  "filename.tcf"
 map name Name of GRASS ASCII map containing values of the canopy optical transmission coefficient. (0.0 - 1.0). 
VHEIGHT  "filename.vht"
 map name Name of GRASS ASCII map containing values of the vegetation height in m. This value is used in calculating the aerodynamic resistance of the reference crop (m) and used in assigning root depth when using INF_RICHARDS. 
CANOPY  "filename.cpy"
 map name Name of GRASS ASCII map containing values of the canopy average stomatal resistance (s/m).

3.8.5 Optional Inputs

Card Argument Units Description 
TOP_LAYER_DEPTH ##.##
 real m If using GAR, can specify a top layer that is less than or equal to SOIL_MOIST_DEPTH, default is SOIL_MOIST_DEPTH (m). 
END_TIME [yr mo day hr min]
 date and time date and time Absolute date and time to end the long term simulation. Takes the form year month day hour min, such as 2002 6 30 24 00. Used for stopping the simulation before the end of data. 
START_DATE [yr mo day ]
 date year month day Absolute date to start the long term simulation. Takes the form year month day, such as 2002 6 30. Used for starting the the simulation after the beginning of the hmet data start. Must be used with START_TIME. Start time and date must coincide with a date and time in the hmet series that is not within a precipitation event. 
START_TIME [hr min]
 time hour minute Absolute date and time to end the long term simulation. Takes the form of hour min, 24 00. Used for starting the the simulation after the beginning of the hmet data start. Must be used with START_DATE. Start time and date must coincide with a date and time in the hmet series that is not within a precipitation event.

3.8.6 Snow Card Inputs - Optional

Prior to version 6.1 there are no snow options. Additional snow capability has been added in v6.1 and beyond. Please note the GSSHA version numbers when using these cards.

Cards calling which snow melt algorithm to use

Melt Method Card Description
Hybrid Energy Balance 
default (no card required)
 The Hybrid Energy Balance Method for melting snow is the default, so it is utilized if NWSRFS_SNOW and EB_SNOW are not present in the Project File.
Temperature Index 
NWSRFS_SNOW
 The Temperature Index Method for melting snow is utilized if this card is present in the Project File.
Energy Balance 
EB_SNOW
 The Energy Balance Method for melting snow is utilized if this card is present in the Project File.

Cards Associated with All Three Melt Methods

Card Argument Units Description 
NWSRFS_SCF     ##.##
 real fraction Snow Cover Factor (adjusts for mis-readings in the gage data (see Continuous:Snowfall_Accumulation_and_Melting). 
SNOW_TEMP_BASE ##.##
 real °C Base Temperature (MBASE) at which melt begins in snow. 
SNOW_NO_INFILTRATE
     This option prevents infiltration in any cell containing snow. 
INIT_SWE_DEPTH #.# or File
 real or File m Initializes the snow water equivalent (SWE) for the entire model. If a value is specified the entire model initializes with that value of SWE. A map file may also be specified. The projection and spatial coordinates must be the same as the model. An example input file is shown below. 
SNOW_SWE_FILE  ***.swe
 File m Outputs time-series snow water equivalent maps (similar to DEP file).

Example file when using INIT_SWE_DEPTH
Init Snow.jpg


Cards Associated with BOTH Hybrid Energy Balance and Temperature Index Methods

Card Argument Units Description 
NWSRFS_FR_USE  ##.##
 real fraction Specifies the fraction of precipitation in the form of rain when the temperature in the cell drops below MBASE. 
NWSRFS_TIPM       ##.##
 real   Snow Cover Thermal Gradient 
NWSRFS_NMF        ##.##
 real mm/°C/dt Negative Melt Factor. 
NWSRFS_FUA        ##.##
 real   Empirical Wind Function Factor. 
NWSRFS_PLWHC      ##.##
 real  % Percent Liquid Water Holding Capacity. 
NWSRFS_ELEV_SNOW  File
 File depends on parameter This card allows some of the parameters related to snow to be varied depending on elevation using elevation bands. Model elevation (*.ele file) must be in meters. The format of the input file is shown below.

Example file when using NWSRFS_ELEV_SNOW
Band NWSRFS.jpg
Elevations are in meters, all other values are in their standard formats.

Cards Associated with JUST Temperature Index Method

Card Argument Units Description 
NWSRFS_MF_MAX  ##.##
 real mm/°C/dt Maximum Melt Factor, only works with NWSRFS_SNOW. 
NWSRFS_MF_MIN  ##.##
 real mm/°C/dt Minimum Melt Factor, only works with NWSRFS_SNOW.

Cards Associated with Vertical Melt Water Transport (Vertical MWT)

Card Argument Units Description 
SNAP_RETENTION
     Uses the SNAP model (Albert & Krajeski, 1998) to simulate the vertical transport of melt-water through the snow pack. Available in versions 6.2 and beyond. (Vertical MWT). 
VERT_SNOW_RETENTION
     Uses the SNAP model (Albert & Krajeski, 1998) to simulate the vertical transport of melt-water through the snow pack (Vertical MWT), but also distributes the melt incrementally over an hour instead of abruptly at every timestep that SNAP is run (which is hourly). Available in versions 6.2 and beyond.

Cards Associated with Lateral Melt Water Transport (Lateral MWT)

Card Argument Units Description 
ROUTE_LAT_SNOW     ##.##
 none Simulates the lateral transport of melt-water through the snow pack based on work by Colbeck (1974) (Lateral MWT). The hydraulic conductivity is calculated over time according to the SNAP model (Albert & Krajeski, 1998) unless the user specifies a value with the SNOW_DARCY card. In versions 6.1 and beyond. 
SNOW_DARCY     ##.##
 real m s-1 Simulates the lateral transport of melt-water through the snow pack based on work by Colbeck (1974) (Lateral MWT). The user specifies the hydraulic conductivity of the snow pack (m s-1) used for the duration of the simulation. In versions 6.1 and beyond.

Cards Associated with Orographic Effects Orographic effects are available in v6.1 and beyond. Note that the cards change between versions 6.1 and v6.2

Card Argument Units Description 
HMET_OROG_GAGES  ***.txt
 File see Orographic Effects Adjusts the temperature in each cell based on elevation differences between the cell and multiple gage sites. Requires HMET_ELEV_GAGE. The file must have a specific format as shown in Orographic Effects. Model elevations (*.ele file) must be in meters. Available in version 6.1 and beyond. Do not use when using OROGRVAR_HMET in v6.1 or with YES_DALR_FLAG in v6.2 and beyond. 
HMET_ELEV_GAGE   ##.##
 real m Elevation (m) of the gage site where temperature is measured. For GSSHA v6.1 include the OROGVAR_HMET and HMET_LAPSE_RATE cards in the Project File. For versions 6.2 and beyond include the YES_DALR_FLAG in the project file if you want to specify the lapse rate, otherwise GSSHA calculates the lapse rate. 
OROGVAR_HMET
     Adjusts the temperature in each cell based on elevation differences between the cell and the gage site (Orographic Effects). Works only when the HMET_ELEV_GAGE and HMET_LAPSE_RATE cards are included in the Project File. Only one temperature gage used for this option. Does not work with and is exclusive with HMET_OROG_GAGES. Model elevation (*.ele file) must be in meters. Use for version 6.1. For version 6.2 and beyond use YES_DALR_FLAG, described below. 
HMET_LAPSE_RATE  ##.##
 real °C km-1 Dry adiabatic lapse rate of the area modeled. Works only when the OROGVAR_HMET and HMET_ELEV_GAGE cards are included in the project Project File. Used in version 6.1. Exclusive to HMET_OROG_GAGES. In v6.2 and beyond use YES_DALR_FLAG, as described below. 
YES_DALR_FLAG  ##.##
 real °C m-1 Dry adiabatic lapse rate of the area modeled. Works only when the HMET_ELEV_GAGE card is included in the Project File. Use for versions 6.2 and beyond. Exclusive to HMET_OROG_GAGES. For versions 6.1 use the OROGVAR_HMET and HMET_LAPSE_RATE cards, as described above.

3.8.7 Distributed Hydrometeorology Data - Optional

This function allows GSSHA to read in raster-based hydrometeorology data. The input files must be in the same projection as the GSSHA model and must be larger than the model domain. Please see Distributed HMET Data for more details.

Card Argument Units Description 
HMET_ASCII  ***.txt
 File see Distributed HMET Data Inputs hyrometeorology data (temperature, cloud cover, direct radiation, global radiation, pressure, relative humidity, and wind speed) in each cell based on hourly Arc/Info ASCII grid files, giving the model more spatial variability. The files must have a specific format as described in Distributed HMET Data.

3.8.8 Continuous Frozen Ground Index (CFGI) Index Model - Optional

These options are only valid with verions 6.2 and later. In previous versions the CFGI model is applied for any LONG_TERM simulations.

Card Argument Units Description 
CFGI
none Use the CFGI model to simulate frozen soil effects. 
CFGI_INDEX
real degree C hours Threshold value (negative degree C hours) to differentiate between frozen and unfrozen soils. Default: 83.0. 
CFGI_K
real dimensionless Snow thermal effect constant (K) in CFGI equation. Default: 0.5. 
GTFSM
 none dimensionless Use frozen soil hydraulic conductivity equation. If not used then assumed to be 0.




GSSHA User's Manual

3 Project File
3.1     Required Inputs
3.2     Mapping Table – Optional
3.3     Overland Flow – Required
3.4     Interception – Optional
3.5     Rainfall Input and Options – Required
3.6     Infiltration – Optional
3.7     Channel Routing – Optional
3.8     Continuous Simulations – Optional
3.9     Saturated Groundwater Flow – Optional
3.10     Soil Erosion – Optional
3.11     Constituent Transport – Optional
3.12     Subsurface Drainage Network – Optional
3.13     Output Files – Required


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