pyart.correct.phase_proc_lp#

pyart.correct.phase_proc_lp(radar, offset, debug=False, self_const=60000.0, low_z=10.0, high_z=53.0, min_phidp=0.01, min_ncp=0.5, min_rhv=0.8, fzl=4000.0, sys_phase=0.0, overide_sys_phase=False, nowrap=None, really_verbose=False, LP_solver='cvxopt', refl_field=None, ncp_field=None, rhv_field=None, phidp_field=None, kdp_field=None, unf_field=None, window_len=35, proc=1, coef=0.914)[source]#

Phase process using a LP method [1].

Parameters:

  • radar (Radar) – Input radar.

  • offset (float) – Reflectivity offset in dBz.

  • 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.

  • min_phidp (float, optional) – Minimum Phi differential phase.

  • min_ncp (float, optional) – Minimum normal coherent power.

  • min_rhv (float, optional) – Minimum copolar coefficient.

  • fzl (float, optional) – Maximum altitude.

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

  • overide_sys_phase (bool, optional) – True to use sys_phase as the system phase. False will calculate a value automatically.

  • 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

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.