Detailed Description

Atmospheric transmissivity generator.

Generate the atmospheric transmissivity (or clearness index, see meteoparam) from other parameters. If a parameter named "CLD" is available, it will be interpreted as cloud cover / cloudiness: in okta between 0 (fully clear) and 8 (fully cloudy). For synop reports, it is possible to include a value of exactly 9 (sky obstructed from view by fog, heavy precipitation...) that will be transparently reset to 8 (fully cloudy).

If no such parameter is available, the atmospheric transmissivity is calculated from the solar index (ratio of measured iswr to potential iswr, therefore using the current location (lat, lon, altitude) and ISWR to parametrize the cloud cover). This relies on (Kasten and Czeplak, 1980).

It takes the following (optional) argument:

CLD_TYPE: cloudiness model, either LHOMME, KASTEN or CRAWFORD (default: KASTEN, see AllSkyLWGenerator for the references of the papers. Please also note that CRAWFORD and LHOMME are exactly identical as the both simply consider that the cloudiness is 1-clearness_index);
SHADE_FROM_DEM: if set to true, the DEM defined in the [Input] section will be used to compute the shading;
INFILE: a file containing the horizon for some or all stations (see the ProcShade filter for the format);
OUTFILE: a file to write the computed horizons to. If some horizons have been read from INFILE, they will also be written out in OUTFILE;
USE_RSWR. If set to TRUE, when no ISWR is available but RSWR and HS are available, a ground albedo is estimated (either soil or snow albedo) and ISWR is then computed from RSWR. Unfortunately, this is not very precise... (thus default is false)
USE_RAD_THRESHOLD: when relying on measured ISWR to parametrize the cloudiness, there is a risk that the measuring station would stand in a place where it is shaded by the surrounding terrain at some point during the day. This would lead to an overestimation of the cloudiness that is undesirable. In this case, it is possible to set USE_RAD_THRESHOLD to TRUE in order to interpolate the cloudiness over all periods of low radiation measured ISWR. This is less performant that only considering the solar elevation (with shading computed from DEM) but improves things in this specific scenario, when no shading is available.

Note: Please note that it is possible to combine SHADE_FROM_DEM and INFILE: in this case, stations that don't have any horizon in the provided INFILE will be computed from DEM. It is also possible to define wildcard station ID in the horizon file. If SHADE_FROM_DEM has been set to false and no INFILE has been provided, a fixed 5 degrees threshold is used.

[Generators]
TAU_CLD::generator1     = TAU_CLD
TAU_CLD::arg1::use_rswr = false

The horizon file contains on each line a station ID followed by an azimuth (in degrees, starting from North) and an elevation above the horizontal (also in degrees). It is possible to define a wildcard station ID '*' to be used as fallback. The elevation for any given azimuth will be linearly interpolated between the provided horizons before and after. If only one azimuth is given for a station ID, its horizon elevation is assumed to be constant. See below an example horizon file, defining two station IDs (SLF2 and FLU2):

SLF2 0 5
SLF2 45 25
SLF2 180 30
SLF2 245 10
FLU2 0 7

Note: In order to pre-compute the horizons for multiple stations, write an ini file reading all stations of interest, declare a dataGenerator that relies on TauCLDGenerator and run meteoio_timeseries on it for at least one time step. This will be enough to create the horizon file for all stations...

#include <TauCLDGenerator.h>

Public Types
enum	clf_parametrization { DEFAULT , CLF_LHOMME , KASTEN , CLF_CRAWFORD }

Public Member Functions
	TauCLDGenerator (const std::vector< std::pair< std::string, std::string > > &vecArgs, const std::string &i_algo, const std::string &i_section, const double &TZ, const Config &i_cfg)

	~TauCLDGenerator ()

bool	generate (const size_t &param, MeteoData &md, const std::vector< MeteoData > &vecMeteo)

bool	create (const size_t &param, const size_t &ii_min, const size_t &ii_max, std::vector< MeteoData > &vecMeteo)
	Fill one time series of MeteoData for one station. More...

Public Member Functions inherited from mio::GeneratorAlgorithm
virtual	~GeneratorAlgorithm ()

virtual bool	generate (const size_t &param, MeteoData &md, const std::vector< MeteoData > &vecMeteo)=0

virtual bool	create (const size_t &param, const size_t &ii_min, const size_t &ii_max, std::vector< MeteoData > &vecMeteo)=0
	Fill one time series of MeteoData for one station. More...

bool	skipStation (const std::string &station_id) const
	Should this station be skipped, based on user-provided station ID restrictions? More...

bool	skipTimeStep (const Date &dt) const
	Should this timestep be skipped, based on user-provided time restrictions? More...

std::vector< DateRange >	getTimeRestrictions () const

std::string	getAlgo () const

Protected Member Functions
double	interpolateCloudiness (const std::string &station_hash, const double &julian_gmt) const

double	getCloudiness (const MeteoData &md)
	Return the atmospheric cloudiness. More...

double	computeCloudiness (const MeteoData &md, bool &is_night)
	Compute the atmospheric cloudiness from the available measurements. More...

double	getClearness (const double &cloudiness) const
	Compute the clearness index from an atmospheric cloudiness value. More...

double	getHorizon (const MeteoData &md, const double &sun_azi)

Protected Member Functions inherited from mio::GeneratorAlgorithm
	GeneratorAlgorithm (const std::vector< std::pair< std::string, std::string > > &vecArgs, const std::string &i_algo, const std::string &i_section, const double &TZ)
	protected constructor only to be called by children More...

virtual void	parse_args (const std::vector< std::pair< std::string, std::string > > &)

Static Protected Member Functions
static std::vector< std::pair< double, double > >	computeMask (const DEMObject &i_dem, const StationData &sd)

Static Protected Member Functions inherited from mio::GeneratorAlgorithm
static std::set< std::string >	initStationSet (const std::vector< std::pair< std::string, std::string > > &vecArgs, const std::string &keyword)

Protected Attributes
std::map< std::string, cloudCache >	last_cloudiness

std::map< std::string, std::vector< std::pair< double, double > > >	masks

std::string	horizons_outfile

const Config &	cfg

DEMObject	dem

SunObject	sun

clf_parametrization	cloudiness_model

bool	use_rswr

bool	use_rad_threshold

bool	write_mask_out

bool	use_horizons

bool	from_dem

Protected Attributes inherited from mio::GeneratorAlgorithm
const std::vector< DateRange >	time_restrictions

const std::set< std::string >	excluded_stations

const std::set< std::string >	kept_stations

const std::string	algo

const std::string	section

Additional Inherited Members
Static Protected Attributes inherited from mio::GeneratorAlgorithm
static const double	soil_albedo = .23

static const double	snow_albedo = .85

static const double	snow_thresh = .1

Member Enumeration Documentation

◆ clf_parametrization

enum mio::TauCLDGenerator::clf_parametrization

Enumerator
DEFAULT
CLF_LHOMME
KASTEN
CLF_CRAWFORD

Constructor & Destructor Documentation

◆ TauCLDGenerator()

mio::TauCLDGenerator::TauCLDGenerator	(	const std::vector< std::pair< std::string, std::string > > &	vecArgs,
		const std::string &	i_algo,
		const std::string &	i_section,
		const double &	TZ,
		const Config &	i_cfg
	)

◆ ~TauCLDGenerator()

mio::TauCLDGenerator::~TauCLDGenerator ( )

Member Function Documentation

◆ computeCloudiness()

double mio::TauCLDGenerator::computeCloudiness	(	const MeteoData &	md,
		bool &	is_night
	)

protected

Compute the atmospheric cloudiness from the available measurements.

The clearness index (ie the ratio of the incoming short wave radiation over the ground potential radiation, projected on the horizontal) is computed and used to evaluate the cloudiness, based on the chosen parametrization.

Parameters

[in]	md	MeteoData be a soil ro a snow albedo
[out]	is_night	set to TRUE if it is night time

Returns: cloudiness (between 0 and 1) or IOUtils::nodata

◆ computeMask()

std::vector< std::pair< double, double > > mio::TauCLDGenerator::computeMask	(	const DEMObject &	i_dem,
		const StationData &	sd
	)

staticprotected

◆ create()

bool mio::TauCLDGenerator::create	(	const size_t &	param,
		const size_t &	ii_min,
		const size_t &	ii_max,
		std::vector< MeteoData > &	vecMeteo
	)

virtual

Fill one time series of MeteoData for one station.

This is used by the dataCreators to create a new parameter in one go for the whole timeseries.

Parameters

[in]	param	meteo parameter to generate
[in]	ii_min	minimum index to apply it to in vecMeteo
[in]	ii_max	maximum index to apply it to in vecMeteo
[in]	vecMeteo	meteo timeseries to process

Returns: true if all missing data points for the given parameter could be generated, false otherwise

Implements mio::GeneratorAlgorithm.

◆ generate()

bool mio::TauCLDGenerator::generate	(	const size_t &	param,
		MeteoData &	md,
		const std::vector< MeteoData > &	vecMeteo
	)

virtual

Implements mio::GeneratorAlgorithm.

◆ getClearness()

double mio::TauCLDGenerator::getClearness ( const double & cloudiness ) const

protected

Compute the clearness index from an atmospheric cloudiness value.

This is a convenience method that helps process the same way various types of inputs: if a cloudiness is provided (which is quite rare), it can be converted to a clearness index (ie the ratio of the incoming short wave radiation over the ground potential radiation, projected on the horizontal) and then processed the same way as more traditional measurements (ie only ISWR provided) where it will be re-converted to a cloudiness (thus falling abck to the same cloudiness as originally provided).

Parameters

[in] cloudiness cloudiness (between 0 and 1)

Returns: clearness index (between 0 and 1)

◆ getCloudiness()

double mio::TauCLDGenerator::getCloudiness ( const MeteoData & md )

protected

Return the atmospheric cloudiness.

Based on the available data, it might be a direct copy of a cloudiness value available in the Meteodata, a parametrization based on clearness index (ie the ratio of the incoming short wave radiation over the ground potential radiation, projected on the horizontal) or a temporal interpolations (over the night or while the AWS is in the shade of the terrain).

Parameters

[in] md MeteoData

Returns: cloudiness (between 0 and 1)

◆ getHorizon()

double mio::TauCLDGenerator::getHorizon	(	const MeteoData &	md,
		const double &	sun_azi
	)

protected

◆ interpolateCloudiness()

double mio::TauCLDGenerator::interpolateCloudiness	(	const std::string &	station_hash,
		const double &	julian_gmt
	)		const

protected

Member Data Documentation

◆ cfg

const Config& mio::TauCLDGenerator::cfg

protected

◆ cloudiness_model

clf_parametrization mio::TauCLDGenerator::cloudiness_model

protected

◆ dem

DEMObject mio::TauCLDGenerator::dem

protected

◆ from_dem

bool mio::TauCLDGenerator::from_dem

protected

◆ horizons_outfile

std::string mio::TauCLDGenerator::horizons_outfile

protected

◆ last_cloudiness

std::map< std::string, cloudCache > mio::TauCLDGenerator::last_cloudiness

protected

◆ masks

std::map< std::string , std::vector< std::pair<double,double> > > mio::TauCLDGenerator::masks

protected

◆ sun

SunObject mio::TauCLDGenerator::sun

protected

◆ use_horizons

bool mio::TauCLDGenerator::use_horizons

protected

◆ use_rad_threshold

bool mio::TauCLDGenerator::use_rad_threshold

protected

◆ use_rswr

bool mio::TauCLDGenerator::use_rswr

protected

◆ write_mask_out

bool mio::TauCLDGenerator::write_mask_out

protected

The documentation for this class was generated from the following files:

Detailed Description

Public Types

Public Member Functions

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Additional Inherited Members

Member Enumeration Documentation

◆ clf_parametrization

Constructor & Destructor Documentation

◆ TauCLDGenerator()

◆ ~TauCLDGenerator()

Member Function Documentation

◆ computeCloudiness()

◆ computeMask()

◆ create()

◆ generate()

◆ getClearness()

◆ getCloudiness()

◆ getHorizon()

◆ interpolateCloudiness()

Member Data Documentation

◆ cfg

◆ cloudiness_model

◆ dem

◆ from_dem

◆ horizons_outfile

◆ last_cloudiness

◆ masks

◆ sun

◆ use_horizons

◆ use_rad_threshold

◆ use_rswr

◆ write_mask_out