Global snowmelt processing methods. More...

Collaboration diagram for Global Snowmelt Processing Methods:

Functions
int	snow_readMeltParams (char *tok[], int ntoks)
	Reads snowmelt parameters from a tokenized line of input data.

int	snow_createSnowpack (int subcatchIndex, int snowIndex)
	Creates a snowpack object for a subcatchment.

void	snow_validateSnowmelt (int snowIndex)
	Checks for valid values in a snowmelt parameter set.

void	snow_initSnowpack (int subcatchIndex)
	Initializes state of a subcatchment's snowpack.

void	snow_initSnowmelt (int snowIndex)
	Initializes values in a snowmelt parameter set.

void	snow_getState (int i, int j, double x[])
	Retrieves the current state of a snowpack object.

void	snow_setState (int subcatchIndex, int subAreaIndex, double x[])
	Sets the current state of a snowpack object.

void	snow_setMeltCoeffs (int snowIndex, double season)
	Sets values of snowmelt coefficients for a particular time of year.

void	snow_plowSnow (int subcatchIndex, double tStep)
	Adds new snow to subcatchment and plows it between sub-areas.

double	snow_getSnowMelt (int subcatchIndex, double rainfall, double snowfall, double tStep, double netPrecip[])
	Modifies rainfall input to subcatchment's subareas based on possible snow melt and updates snow depth over entire subcatchment.

double	snow_getSnowCover (int subcatchIndex)
	Computes volume of snow on a subcatchment.

Detailed Description

Global snowmelt processing methods.

Function Documentation

◆ snow_createSnowpack()

int snow_createSnowpack	(	int	subcatchIndex,
		int	snowIndex )

Creates a snowpack object for a subcatchment.

Parameters

[in]	subcatchIndex	Subcatchment index
[in]	snowIndex	Snowmelt parameter set index

Returns: TRUE if successful, FALSE if not

Creates a snowpack object for a subcatchment.

Implementation arguments

subcatchIndex (in): Valid subcatchment index; no existing owned snowpack may be overwritten without first releasing it.
snowIndex (in): Valid snowmelt parameter-set index stored in the new pack.

Returns: TRUE after allocation and attachment, FALSE if allocation fails.

Note: Only snowmeltIndex is initialized here. Call snow_initSnowpack() before using state arrays; the project owns the allocated snowpack.

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◆ snow_getSnowCover()

double snow_getSnowCover ( int subcatchIndex )

Computes volume of snow on a subcatchment.

Parameters

[in] subcatchIndex Subcatchment index

Returns: Volume of snow cover (ft3)

Computes volume of snow on a subcatchment.

Implementation arguments

subcatchIndex (in): Valid subcatchment index.

Returns: Snowpack water-equivalent volume in cubic feet, or zero when no snowpack exists. Reads all three snow-surface area fractions without modifying state.

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◆ snow_getSnowMelt()

double snow_getSnowMelt	(	int	subcatchIndex,
		double	rainfall,
		double	snowfall,
		double	tStep,
		double	netPrecip[] )

Modifies rainfall input to subcatchment's subareas based on possible snow melt and updates snow depth over entire subcatchment.

Parameters

[in]	subcatchIndex	Subcatchment index
[in]	rainfall	Rainfall (ft/sec)
[in]	snowfall	Snowfall (ft/sec)
[in]	tStep	Time step (sec)
[out]	netPrecip	Rainfall + snowmelt on each runoff sub-area (ft/sec)

Returns: New snow depth over subcatchment

Modifies rainfall input to subcatchment's subareas based on possible snow melt and updates snow depth over entire subcatchment.

Implementation arguments

subcatchIndex (in): Valid subcatchment index with a non-null initialized snowpack.
rainfall (in): Liquid rainfall rate in feet per second.
snowfall (in): Snowfall water-equivalent rate in feet per second.
tStep (in): Positive melt/routing interval in seconds.
netPrecip (out): Borrowed writable array of at least three doubles, receiving rainfall plus melt in ft/s for the runoff subareas. Impervious snow-surface rates are combined into IMPERV0/IMPERV1 entries.

Returns: Area-weighted snow water-equivalent depth in feet.

Postcondition: Advances the selected pack's snow, free-water, cold-content, depletion and immediate-melt state; no output storage is retained.

◆ snow_getState()

void snow_getState	(	int	i,
		int	j,
		double	x[] )

Retrieves the current state of a snowpack object.

Parameters

[in]	i	Subcatchment index
[in]	j	Snowpack sub-area index
[out]	x	Array of snowpack state variables

Retrieves the current state of a snowpack object.

Implementation arguments

i (in): Valid subcatchment index; a missing snowpack leaves x unchanged.
j (in): Snow surface index SNOW_PLOWABLE..SNOW_PERV, in [0, 2].
x (out): Borrowed writable array of at least five doubles: snow water equivalent depth, free water, cold content, antecedent temperature and initial depletion-curve AWESI. Depths use feet and temperature uses degrees F.

Note: Preserves the internal cold-content/depletion representation for snow_setState(); no conversion, validation or storage retention occurs.

◆ snow_initSnowmelt()

void snow_initSnowmelt ( int snowIndex )

Initializes values in a snowmelt parameter set.

Parameters

[in] snowIndex Snowmelt parameter set index

Initializes values in a snowmelt parameter set.

Implementation arguments

snowIndex (in): Valid destination index into Snowmelt.

Postcondition: Clears three-surface melt, water and redistribution properties, sets the plowing trigger to 1e6 and clears the receiving-subcatchment reference.

Note: Does not allocate the Snowmelt array or initialize snowpack objects.

◆ snow_initSnowpack()

void snow_initSnowpack ( int subcatchIndex )

Initializes state of a subcatchment's snowpack.

Parameters

[in] subcatchIndex Subcatchment index

Initializes state of a subcatchment's snowpack.

Implementation arguments

subcatchIndex (in): Valid subcatchment index; a missing snowpack is a no-op.

Postcondition: Sets surface area fractions, snow/free-water depths, cold content, antecedent-temperature index and depletion state from the selected Snowmelt parameters, and writes Subcatch.newSnowDepth in feet of water equivalent.

Precondition: The pack's snowmeltIndex and subcatchment impervious fraction are valid.

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◆ snow_plowSnow()

void snow_plowSnow	(	int	subcatchIndex,
		double	tStep )

Adds new snow to subcatchment and plows it between sub-areas.

Parameters

[in]	subcatchIndex	Subcatchment index
[in]	tStep	Time step (sec)

Adds new snow to subcatchment and plows it between sub-areas.

Implementation arguments

subcatchIndex (in): Valid subcatchment index; missing snowpack is a no-op.
tStep (in): Positive accumulation/plowing interval in seconds.

Postcondition: Updates snow water-equivalent depths, immediate-melt rates, Snow.removed and any receiving subcatchment pack. Gage snowfall is scaled by snowScaleFactor and API snowfall is added before accumulation.

Precondition: Snowmelt redistribution targets and area fractions are validated.

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◆ snow_readMeltParams()

int snow_readMeltParams	(	char *	tok[],
		int	ntoks )

Reads snowmelt parameters from a tokenized line of input data.

Parameters

[in]	tok	Array of string tokens
[in]	ntoks	Number of tokens

Returns: Error code

Format of data are:

Name SubArea Cmin Cmax Tbase FWF SD0 FW0 SNN0/SD100
Name REMOVAL SDplow Fout Fimperv Fperv Fimelt Fsubcatch (Subcatch)

Implementation arguments

tok (in): Array of string tokens

ntoks (in): Number of tokens
Returns
Error code
Format of data are:
Name SubArea Cmin Cmax Tbase FWF SD0 FW0 SNN0/SD100
Name REMOVAL SDplow Fout Fimperv Fperv Fimelt Fsubcatch (Subcatch)

Reads snow melt parameters from a tokenized line of input data. Format of data are: Name SubArea Cmin Cmax Tbase FWF SD0 FW0 SNN0/SD100 Name REMOVAL SDplow Fout Fimperv Fperv Fimelt Fsubcatch (Subcatch).

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◆ snow_setMeltCoeffs()

void snow_setMeltCoeffs	(	int	snowIndex,
		double	season )

Sets values of snowmelt coefficients for a particular time of year.

Parameters

[in]	snowIndex	Snowmelt parameter set index
[in]	season	Season of the year

Sets values of snowmelt coefficients for a particular time of year.

Implementation arguments

snowIndex (in): Valid Snowmelt parameter-set index.
season (in): Dimensionless seasonal factor, normally in [-1, 1]; -1 selects dhmin and +1 selects dhmax. Values are not clamped.

Postcondition: Stores interpolated dhm coefficients in the parameter set's internal units.

◆ snow_setState()

void snow_setState	(	int	subcatchIndex,
		int	subAreaIndex,
		double	x[] )

Sets the current state of a snowpack object.

Parameters

[in]	subcatchIndex	Subcatchment index
[in]	subAreaIndex	Snowpack sub-area index
[in]	x	Array of snowpack state variables

Sets the current state of a snowpack object.

Implementation arguments

subcatchIndex (in): Valid subcatchment index; missing snowpack is a no-op.
subAreaIndex (in): Snow surface index SNOW_PLOWABLE..SNOW_PERV, in [0, 2].
x (in): Borrowed readable array of at least five doubles in exactly the order/internal units returned by snow_getState().

Postcondition: Copies all five values without validation; aggregate subcatchment snow depth is not recomputed here. Input storage is not retained.

◆ snow_validateSnowmelt()

void snow_validateSnowmelt ( int snowIndex )

Checks for valid values in a snowmelt parameter set.

Parameters

[in] snowIndex Snowmelt parameter set index

Checks for valid values in a snowmelt parameter set.

Implementation arguments

snowIndex (in): Valid parameter-set index into Snowmelt.

Postcondition: Reports ERR_SNOWPACK_PARAMS if min melt coefficients exceed maxima, free-water or plowable fractions lie outside [0, 1], or redistribution fractions sum above 1.01. Does not repair parameter values.

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Functions

Detailed Description

Function Documentation

◆ snow_createSnowpack()

◆ snow_getSnowCover()

◆ snow_getSnowMelt()

◆ snow_getState()

◆ snow_initSnowmelt()

◆ snow_initSnowpack()

◆ snow_plowSnow()

◆ snow_readMeltParams()

◆ snow_setMeltCoeffs()

◆ snow_setState()

◆ snow_validateSnowmelt()