pyart.correct.calculate_attenuation#

pyart.correct.calculate_attenuation(radar, z_offset, debug=False, doc=15, fzl=4000.0, gatefilter=None, rhv_min=0.8, ncp_min=0.5, a_coef=0.06, beta=0.8, refl_field=None, ncp_field=None, rhv_field=None, phidp_field=None, spec_at_field=None, corr_refl_field=None)[source]#

Calculate the attenuation from a polarimetric radar using Z-PHI method.

Parameters:

  • radar (Radar) – Radar object to use for attenuation calculations. Must have copol_coeff, norm_coherent_power, proc_dp_phase_shift, reflectivity_horizontal fields.

  • z_offset (float) – Horizontal reflectivity offset in dBZ.

  • debug (bool, optional) – True to print debugging information, False supressed this printing.

  • doc (float, optional) – Number of gates at the end of each ray to to remove from the calculation.

  • fzl (float, optional) – Freezing layer, gates above this point are not included in the correction.

  • gatefilter (GateFilter, optional) – The gates to exclude from the calculation. This, combined with the gates above fzl, will be excluded from the correction. Set to None to not use a gatefilter.

  • rhv_min (float, optional) – Minimum copol_coeff value to consider valid.

  • ncp_min (float, optional) – Minimum norm_coherent_power to consider valid.

  • a_coef (float, optional) – A coefficient in attenuation calculation.

  • beta (float, optional) – Beta parameter in attenuation calculation.

  • refl_field (str, optional) – Name of the reflectivity field used for the attenuation correction. A value of None for any of these parameters will use the default field name as defined in the Py-ART configuration file.

  • phidp_field (str, optional) – Name of the differential phase field used for the attenuation correction. A value of None for any of these parameters will use the default field name as defined in the Py-ART configuration file.

  • ncp_field (str, optional) – Name of the normalized coherent power field used for the attenuation correction. A value of None for any of these parameters will use the default field name as defined in the Py-ART configuration file.

  • zdr_field (str, optional) – Name of the differential reflectivity field used for the attenuation correction. A value of None for any of these parameters will use the default field name as defined in the Py-ART configuration file. This will only be used if it is available.

  • spec_at_field (str, optional) – Name of the specific attenuation field that will be used to fill in the metadata for the returned fields. A value of None for any of these parameters will use the default field names as defined in the Py-ART configuration file.

  • corr_refl_field (str, optional) – Name of the corrected reflectivity field that will be used to fill in the metadata for the returned fields. A value of None for any of these parameters will use the default field names as defined in the Py-ART configuration file.

Returns:

  • spec_at (dict) – Field dictionary containing the specific attenuation.

  • cor_z (dict) – Field dictionary containing the corrected reflectivity.

References

Gu et al. Polarimetric Attenuation Correction in Heavy Rain at C Band, JAMC, 2011, 50, 39-58.