pyart.retrieve.melting_layer_mf#

pyart.retrieve.melting_layer_mf(radar, nvalid_min=180, ml_thickness_min=200.0, ml_thickness_max=1400.0, ml_thickness_step=100.0, iso0_max=4500.0, ml_top_diff_max=700.0, ml_top_step=100.0, rhohv_snow=0.99, rhohv_rain=0.99, rhohv_ml=0.93, zh_snow=20.0, zh_rain=20.0, zh_ml=27.0, zv_snow=20.0, zv_rain=20.0, zv_ml=26.0, h_max=6000.0, h_res=1.0, beam_factor=2.0, npts_diagram=81, rng_bottom_max=200000.0, ns_factor=0.6, rhohv_corr_min=0.9, rhohv_nash_min=0.5, ang_iso0=10.0, age_iso0=3.0, ml_thickness_iso0=700.0, ml_memory=None, rhohv_field_obs=None, temp_field=None, iso0_field=None, rhohv_field_theo=None, ml_field=None, ml_pos_field=None, temp_ref=None, get_iso0=True)[source]#

Detects the melting layer following the approach implemented at Meteo-France

Parameters:

radar (radar) – radar object

Other Parameters:

  • nvalid_min (int) – Number of volume scans to aggregate

  • ml_thickness_min, ml_thickness_max, ml_thickness_step (float) – Minimum, maximum and step of the melting layer thickness of the models to explore [m]

  • iso0_max (maximum iso0 altitude [masl])

  • ml_top_diff_max, ml_top_step (float) – maximum difference +- between iso-0 and top of the melting layer [m] of the models to explore. Step

  • rhohv_snow, rhohv_rain, rhohv_ml (float) – values of RhoHV above, below and at the peak of the melting layer used to construct the model

  • zh_snow, zh_rain, zh_ml (float) – values of horizontal reflectivity above, below and at the peak of the melting layer used to construct the model

  • zv_snow, zv_rain, zv_ml (float) – values of vertical reflectivity above, below and at the peak of the melting layer used to construct the model

  • h_max (float) – maximum altitude [masl] where to compute the model RhoHV profile

  • h_res (float) – resolution of the model RhoHV profile

  • beam_factor (float) – factor by which to multiply the antenna beamwidth. Used to select the range of angles where the antenna pattern is going to be computed

  • rng_bottom_max (float) – Maximum range up to which the bottom of the melting layer can be placed in order to try to find a suitable model

  • ns_factor (float) – multiplicative factor applied to the number of valid model gates when comparing with the valid observations to decide whether the observations and the model can be compared

  • rhohv_corr_min, rhohv_nash_min (float) – minimum correlation and NSE to consider the comparison between model and observations valid

  • ang_iso0 (float) – the equivalent iso0 angle; Used for the computation of the weights

  • age_iso0 (float) – the equivalent age of the iso0 (hours)

  • ml_thickness_iso0 (float) – Default iso-0 thickness

  • ml_memory (dict or None) – dictionary containing the memory of past retrievals

  • rhohv_field_obs, temp_field, iso0_field (str) – name of the RhoHV observed field, temperature field and height over iso0 field

  • rhohv_field_theo (str) – name of the RhoHV modelled field

  • ml_field (str) – Output. Field name which represents the melting layer field. A value of None will use the default field name as defined in the Py-ART configuration file.

  • ml_pos_field (str) – Output. Field name which represents the melting layer top and bottom height field. A value of None will use the default field name as defined in the Py-ART configuration file.

  • temp_ref (str) – the field use as reference for temperature. Can be temperature or height_over_iso0.

  • get_iso0 (bool) – returns height w.r.t. freezing level top for each gate in the radar volume.

Returns:

  • ml_obj (radar-like object) – A radar-like object containing the field melting layer height with the bottom (at range position 0) and top (at range position one) of the melting layer at each ray.

  • ml_dict (dict) – A dictionary containg the position of the range gate respect to the melting layer and metadata

  • iso0_dict (dict or None) – A dictionary containing the distance respect to the melting layer and metadata

  • ml_found_obj (radar-like object) – A radar-like object containing the field melting layer height with the bottom (at range position 0) and top (at range position one) of the melting layer at each ray. This stores the instantaneous retrieval i.e. the retrieval not averaged in time.