Snow Card Inputs - Optional

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The following tables list all project file cards pertaining to snow accumulation, melt, and melt-water transport.


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_SWE_FILE  ***.swe
File m Outputs time-series snow water equivalent maps (similar to DEP file).


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.


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 (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).



Cards Associated with Lateral Melt Water Transport (Lateral MWT)

Card Argument Units Description
SNOW_DARCY
    Simulates the lateral transport of melt-water through the snow pack based on work by Colbeck (1974) (Lateral MWT).
SNOW_REYNOLDS  ##.##
real   Reynolds Number at which flow simulation switches from Darcian to regular Overland. Only effects cells covered by snow and only works when SNOW_DARCY card present in Project File.



Cards Associated with Orographic Effects

Card Argument Units Description
OROGVAR_HMET
    Adjusts the temperature in each cell based on elevation differences between the cell and the gage site (Orographic Effects).
HMET_ELEV_GAGE   ##.##
real m Elevation (m) of the gage site where temperature is measured. Only works when OROGVAR_HMET card present in Project File.
HMET_LAPSE_RATE  ##.##
real °C km-1 Dry adiabatic lapse rate of the area modeled. Only works when OROGVAR_HMET card present in Project File.


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