MeteoIODoc  2.10.0
mio::AllSkyLWGenerator Class Reference

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)
 
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)
 
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 ()
 
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< DateRangegetTimeRestrictions () 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 getCloudiness (const MeteoData &md, SunObject &sun, 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...
 
- 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, std::pair< double, double > > last_cloudiness
 
std::map< std::string, std::vector< std::pair< double, double > > > masks
 
std::string horizons_outfile
 
const Configcfg
 
DEMObject dem
 
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< DateRangetime_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 
)

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]parammeteo parameter to generate
[in]ii_minminimum index to apply it to in vecMeteo
[in]ii_maxmaximum index to apply it to in vecMeteo
[in]vecMeteometeo 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 
)
virtual

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