pyart.correct.dealias_region_based

pyart.correct.dealias_region_based(radar, ref_vel_field=None, interval_splits=3, interval_limits=None, skip_between_rays=100, skip_along_ray=100, centered=True, nyquist_vel=None, check_nyquist_uniform=True, gatefilter=False, rays_wrap_around=None, keep_original=False, set_limits=True, vel_field=None, corr_vel_field=None, **kwargs)

Dealias Doppler velocities using a region based algorithm.

Performs Doppler velocity dealiasing by finding regions of similar velocities and unfolding and merging pairs of regions until all regions are unfolded. Unfolding and merging regions is accomplished by modeling the problem as a dynamic network reduction.

Parameters:

• radar (Radar) – Radar object containing Doppler velocities to dealias.

• ref_vel_field (str or None, optional) – Field in radar containing a reference velocity field used to anchor the unfolded velocities once the algorithm completes. Typically this field is created by simulating the radial velocities from wind data from an atmospheric sonding using pyart.util.simulated_vel_from_profile().

• interval_splits (int, optional) – Number of segments to split the nyquist interval into when finding regions of similar velocity. More splits creates a larger number of initial regions which takes longer to process but may result in better dealiasing. The default value of 3 seems to be a good compromise between performance and artifact free dealiasing. This value is not used if the interval_limits parameter is not None.

• interval_limits (array like or None, optional) – Velocity limits used for finding regions of similar velocity. Should cover the entire nyquist interval. None, the default value, will split the Nyquist interval into interval_splits equal sized intervals.

• skip_between_rays, skip_along_ray (int, optional) – Maximum number of filtered gates to skip over when joining regions, gaps between region larger than this will not be connected. Parameters specify the maximum number of filtered gates between and along a ray. Set these parameters to 0 to disable unfolding across filtered gates.

• centered (bool, optional) – True to apply centering to each sweep after the dealiasing algorithm so that the average number of unfolding is near 0. False does not apply centering which may results in individual sweeps under or over folded by the nyquist interval.

• nyquist_velocity (array like or float, optional) – Nyquist velocity in unit identical to those stored in the radar’s velocity field, either for each sweep or a single value which will be used for all sweeps. None will attempt to determine this value from the Radar object.

• check_nyquist_uniform (bool, optional) – True to check if the Nyquist velocities are uniform for all rays within a sweep, False will skip this check. This parameter is ignored when the nyquist_velocity parameter is not None.

• gatefilter (GateFilter, None or False, optional.) – A GateFilter instance which specified which gates should be ignored when performing de-aliasing. A value of None created this filter from the radar moments using any additional arguments by passing them to moment_based_gate_filter(). False, the default, disables filtering including all gates in the dealiasing.

• rays_wrap_around (bool or None, optional) – True when the rays at the beginning of the sweep and end of the sweep should be interpreted as connected when de-aliasing (PPI scans). False if they edges should not be interpreted as connected (other scan types). None will determine the correct value from the radar scan type.

• keep_original (bool, optional) – True to retain the original Doppler velocity values at gates where the dealiasing procedure fails or was not applied. False does not replacement and these gates will be masked in the corrected velocity field.

• set_limits (bool, optional) – True to set valid_min and valid_max elements in the returned dictionary. False will not set these dictionary elements.

• vel_field (str, optional) – Field in radar to use as the Doppler velocities during dealiasing. None will use the default field name from the Py-ART configuration file.

• corr_vel_field (str, optional) – Name to use for the dealiased Doppler velocity field metadata. None will use the default field name from the Py-ART configuration file.

Returns:

corr_vel (dict) – Field dictionary containing dealiased Doppler velocities. Dealiased array is stored under the ‘data’ key.