Detailed Description

ILWR all sky parametrization.

Using air temperature (TA) and relative humidity (RH) and optionnally cloud transmissivity (TAU_CLD), this offers the choice of several all-sky parametrizations, with the following arguments:

TYPE: specify which parametrization should be used, from the following:
- LHOMME – from Lhomme et al. – "Estimating downward long-wave radiation on the Andean Altiplano", Agric. For. Meteorol., 145, 2007, pp 139–148, doi:10.1016/j.agrformet.2007.04.007
- CARMONA – from Carmona et al., "Estimation of daytime downward longwave radiation under clear and cloudy skies conditions over a sub-humid region." Theoretical and applied climatology 115.1-2 (2014): 281-295.
- CRAWFORD – from Crawford and Duchon, "An Improved Parametrization for Estimating Effective Atmospheric Emissivity for Use in Calculating Daytime Downwelling Longwave Radiation", Journal of Applied Meteorology, 38, 1999, pp 474-480
- OMSTEDT – from Omstedt, "A coupled one-dimensional sea ice-ocean model applied to a semi-enclosed basin", Tellus, 42 A, 568-582, 1990, DOI:10.1034/j.1600-0870.1990.t01-3-00007.
- KONZELMANN – from Konzelmann et al., "Parameterization of global and longwave incoming radiation for the Greenland Ice Sheet." Global and Planetary change 9.1 (1994): 143-164.
- UNSWORTH – from Unsworth and Monteith, "Long-wave radiation at the ground", Q. J. R. Meteorolo. Soc., Vol. 101, 1975, pp 13-24 coupled with a clear sky emissivity following (Dilley, 1998).
it also takes all the arguments of TauCLDGenerator, including the option to provide an Horizon file (see the ProcShade filter for the format).

If no cloud transmissivity is provided in the data, it 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) by default except for Crawford and Lhomme that provide their own parametrizations (it can be forced through the TauCLDGenerator options). The last evaluation of cloud transmissivity is used all along during the times when no ISWR is available (as it is night, or the station stands in the shade or the ISWR measurement is missing) and the last valid value is not too old (ie. no more than 1 day old). The example below gives an example use, providing a file with the horizons for the stations (see TauCLDGenerator) but not relying on a DEM. Of course, it is possible to use the generator without any DEM or horizon file!

[Generators]
ILWR::generator1 = allsky_LW
ILWR::arg1::type = Omstedt
ILWR::arg1::infile = input/horizons.txt
ILWR::arg1::shade_from_dem = FALSE
ILWR::arg1::use_rswr = FALSE

Finally, it is recommended to also use a clear sky generator (declared after this one) for the case of no available short wave measurement (by declaring the ClearSky generator after AllSky).

The graph below shows the comparison between measured and modeled ILWR depending on the chosen parametrization. The measured data (ISWR, TA, RH and the reference ILWR) comes from the Weissfluhjoch *WFJ AWS (2691m, Davos, Switzerland) for the 2010-08-01 – 2019-08-01 period with half-hourly resolution. The data has been binned every 5 W/m², the black dots represent the average of the bin, the greay area contains every data point (ie it shows the minimum and maximum data) while the brown area is defined as average±σ.

Comparison between measured and parametrized ILWR at the Weissfluhjoch *WFJ station (2691m, Davos, Switzerland) for the 2010-08-01 – 2019-08-01 period

#include <AllSkyLWGenerator.h>

Public Member Functions
	AllSkyLWGenerator (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)

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::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 ()

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

Additional Inherited Members
Public Types inherited from mio::TauCLDGenerator
enum	clf_parametrization { DEFAULT , CLF_LHOMME , KASTEN , CLF_CRAWFORD }

Protected Member Functions inherited from mio::TauCLDGenerator
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 inherited from mio::TauCLDGenerator
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 inherited from mio::TauCLDGenerator
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

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

Constructor & Destructor Documentation

◆ AllSkyLWGenerator()

mio::AllSkyLWGenerator::AllSkyLWGenerator	(	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
	)

inline

Member Function Documentation

◆ create()

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