towerpy.profs.polprofs

Towerpy: an open-source toolbox for processing polarimetric radar data.

Classes

PolarimetricProfiles

A class to generate profiles of polarimetric variables.

Module Contents

class towerpy.profs.polprofs.PolarimetricProfiles(radobj=None)

A class to generate profiles of polarimetric variables.

Attributes

elev_anglefloat or list

Elevation angle at which the scan was taken, in deg.

file_namestr or list

Name of the file containing radar data.

scandatetimedatetime or list

Date and time of scan.

site_namestr

Name of the radar site.

georefdict, optional

Descriptor of the computed profiles height.

vpsdict, optional

Profiles generated from a birdbath scan.

vps_statsdict, optional

Statistics of the VPs generation.

qvpsdict, optional

Quasi-Vertical Profiles generated from the PPI scan.

qvps_statsdict, optional

Statistics of the QVPs generation.

rd_qvpsdict, optional

Range-defined Quasi-Vertical Profiles generated from PPI scans taken at different elevation angles.

qvps_itpdict, optional

QVPs generated from each elevation angle.

elev_angle = None

file_name = None

scandatetime = None

site_name = None

profs_type = None

pol_vps(rad_georef, rad_params, rad_vars, thlds=None, valid_gates=0, stats=False)

Generate profiles of polarimetric variables from a birdbath scan.

Parameters

rad_georefdict

Georeferenced data containing descriptors of the azimuth, gates and beam height, amongst others.

rad_paramsdict

Radar technical details.

rad_varsdict

Radar variables used to generate the VPs.

thldsdict containing key and 2-element tuple or list, optional

Thresholds [min, max] of radar variables used to discard gates in the azimuthal averaging. The default is None.

valid_gatesint, optional

Number of valid gates (or azimuths) along the radial. The default is 0.

statsBool, optional

Statistics of the VPs generation:

‘std_dev’: Standard Deviation

‘min’: Min values

‘max’: Max values

‘sem’: Standard Error of the Mean

pol_qvps(rad_georef, rad_params, rad_vars, thlds='default', valid_gates=30, stats=False, exclude_vars=['V [m/s]'], qvps_height_method='bh')

Generate QVPs of polarimetric variables.

Parameters

rad_georefdict

Georeferenced data containing descriptors of the azimuth, gates and beam height, amongst others.

rad_paramsdict

Radar technical details.

rad_varsdict

Radar variables used to generate the QVPs.

thldsdict containing 2-element tuple, optional

Thresholds [min, max] of radar variables used to discard gates in the azimuthal averaging. The default are: ZH [dBZ] > -10 and rhoHV > 0.6, according to [1]_.

valid_gatesint, optional

Number of valid gates (or azimuths) along the radial. The default is 30, according to [1]_.

statsBool, optional

Statistics of the QVPs generation:

‘std_dev’: Standard Deviation

‘min’: Min values

‘max’: Max values

‘sem’: Standard Error of the Mean

exclude_varslist, optional

Name of the variables that will not be used to compute the QVPs. The default is [‘V [m/s]’].

Notes

1. It is recommended to follow the routine described in [2]_ to preprocess \(\Phi_{DP}\) and compute \(K_{DP}\).

References

[1]

Ryzhkov, A. V. et al. (2016) “Quasi-vertical profiles-A new way to look at polarimetric radar data””, Journal of Atmospheric and Oceanic Technology, 33(3), pp. 551–562. https://doi.org/10.1175/JTECH-D-15-0020.1

[2]

Griffin, E. M., Schuur, T. J., & Ryzhkov, A. V. (2018). “A Polarimetric Analysis of Ice Microphysical Processes in Snow, Using Quasi-Vertical Profiles”, Journal of Applied Meteorology and Climatology, 57(1), 31-50. https://doi.org/10.1175/JAMC-D-17-0033.1

pol_rdqvps(rscans_georef, rscans_params, rscans_vars, r0=None, valid_gates=30, thlds='default', power_param1=0, vert_res=2, power_param2=2, spec_range=50, all_desc=True, exclude_vars=['V [m/s]'], qvps_height_method='bh', plot_method=False)

Generate RD-QVPs of polarimetric variables.

Parameters

rscans_georeflist

List of dicts containing the georeference of the PPI scans.

rscans_paramslist

List of dicts containing Radar technical details.

rscans_varslist

List of dicts containing radar variables used to generate the RD-QVPs.

r0float or list of floats, optional

Initial range within the PPI scans to build the QVPS, in km. The default is None.

valid_gatesint, optional

Number of valid gates (or azimuths) along the radial. The default is 30, according to [1]_.

thldsdict containing 2-element tuple, optional

Thresholds [min, max] of radar variables used to discard gates in the azimuthal averaging. The default are: ZH [dBZ] > -10 and rhoHV > 0.6, according to [1]_.

power_param1float, optional

Power parameter for \(r_i \leq d-1\). The default is 0, according to [2]_.

vert_resfloat, optional

Resolution of the common vertical axis, in m. The default is 2.

power_param2float, optional

Power parameter for \(r_i > d-1\). The default is 2, according to [2]_.

spec_rangeint, optional

Range from the radar within which the data will be used. The default is 50.

all_descbool, optional

If False, the function provides descriptors using an average of datetime and elevations and will not give the initial QVPs used to compute the RD-QPVs. The default is True.

exclude_varslist, optional

Name of the variables that will not be used to compute the QVPs. The default is [‘V [m/s]’].

qvps_height_methodstr, optional

‘bh’ or ‘vr’

plot_methodbool, optional

Plot the RD-QVPS. The default is False.

Returns

None.

References

[1]

Ryzhkov, A. V. et al. (2016) ‘Quasi-vertical profiles-A new way to look at polarimetric radar data’, Journal of Atmospheric and Oceanic Technology, 33(3), pp. 551–562. https://doi.org/10.1175/JTECH-D-15-0020.1

[2]

Tobin, D. M., & Kumjian, M. R. (2017). Polarimetric Radar and Surface-Based Precipitation-Type Observations of Ice Pellet to Freezing Rain Transitions, Weather and Forecasting, 32(6), 2065-2082. https://doi.org/10.1175/WAF-D-17-0054.1

[3]

Griffin, E. M., Schuur, T. J., & Ryzhkov, A. V. (2018). A Polarimetric Analysis of Ice Microphysical Processes in Snow, Using Quasi-Vertical Profiles, Journal of Applied Meteorology and Climatology, 57(1), 31-50. https://doi.org/10.1175/JAMC-D-17-0033.1