pyart.correct.phase_proc_lp_gf#

pyart.correct.phase_proc_lp_gf(radar, gatefilter=None, debug=False, self_const=60000.0, low_z=10.0, high_z=53.0, min_phidp=0.01, fzl=4000.0, system_phase=None, nowrap=None, really_verbose=False, LP_solver='cvxopt', refl_field=None, phidp_field=None, kdp_field=None, unf_field=None, window_len=35, proc=1, coef=0.914, ncpts=None, first_gate_sysp=None, offset=0.0, doc=0)[source]#

Phase process using a LP method [1] using Py-ART’s Gatefilter.

Parameters:

  • radar (Radar) – Input radar.

  • gatefilter (Gatefilter, optional) – Py-ART gatefilter object indicating where processing should be carried out

  • debug (bool, optional) – True to print debugging information.

  • self_const (float, optional) – Self consistency factor.

  • low_z (float, optional) – Low limit for reflectivity. Reflectivity below this value is set to this limit.

  • high_z (float, optional) – High limit for reflectivity. Reflectivity above this value is set to this limit.

  • fzl (float, optional) – Maximum altitude.

  • system_phase (float, optional) – System phase in degrees.

  • nowrap (int or None, optional) – Gate number to begin phase unwrapping. None will unwrap all phases.

  • really_verbose (bool, optional) – True to print LPX messaging. False to suppress.

  • LP_solver (‘pyglpk’ or ‘cvxopt’, ‘cylp’, or ‘cylp_mp’, optional) – Module to use to solve LP problem. Default is ‘pyglpk’.

  • refl_field, ncp_field, rhv_field, phidp_field, kdp_field (str, optional) – Name of field in radar which contains the horizonal reflectivity, normal coherent power, copolar coefficient, differential phase shift, and differential phase. A value of None for any of these parameters will use the default field name as defined in the Py-ART configuration file.

  • unf_field (str, optional) – Name of field which will be added to the radar object which will contain the unfolded differential phase. Metadata for this field will be taken from the phidp_field. A value of None will use the default field name as defined in the Py-ART configuration file.

  • window_len (int, optional) – Length of Sobel window applied to PhiDP field when prior to calculating KDP.

  • proc (int, optional) – Number of worker processes, only used when LP_solver is ‘cylp_mp’.

  • coef (float, optional) – Exponent linking Z to KDP in self consistency. kdp=(10**(0.1z))*coef

  • ncpts (int, optional) – Minimum number of points in a ray. Regions within a ray smaller than this or beginning before this gate number are excluded from unfolding.

  • offset (float, optional) – Reflectivity offset to add in dBz.

  • doc (int, optional) – Number of gates to “doc” off the end of a ray.

Returns:

  • reproc_phase (dict) – Field dictionary containing processed differential phase shifts.

  • sob_kdp (dict) – Field dictionary containing recalculated differential phases.

References

[1] Giangrande, S.E., R. McGraw, and L. Lei. An Application of Linear Programming to Polarimetric Radar Differential Phase Processing. J. Atmos. and Oceanic Tech, 2013, 30, 1716.