towerpy.attc.r_att_refl#

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

Classes#

Attn_Refl_Relation

A class to compute the \(A_{H,V}(Z_{H,V})\).

Module Contents#

class towerpy.attc.r_att_refl.Attn_Refl_Relation(radobj=None)[source]#

A class to compute the \(A_{H,V}(Z_{H,V})\).

Attributes#

elev_anglefloat: Elevation angle at which the scan was taken, in deg.
file_namestr: Name of the file containing radar data.
scandatetimedatetime: Date and time of scan.
site_namestr: Name of the radar site.

elev_angle = None[source]#

file_name = None[source]#

scandatetime = None[source]#

site_name = None[source]#

ah_zh(rad_vars, var2calc='ZH [dBZ]', rband='C', temp=20.0, coeff_a=None, coeff_b=None, zh_lower_lim=20.0, zh_upper_lim=50.0, rhohv_lim=0.95, copy_ofr=True, data2correct=None, plot_method=False)[source]#

Compute the \(A_H-Z_H\) relation.

Parameters#

rad_varsdict: Radar object containing at least the specific attenuation \((A_H)\) in dB/km, or the calibrated horizontal reflectivity \((Z_H)\) in dBZ, that will be used for calculations.
var2calcstr: Radar variable to be computed. The string has to be one of ‘AH [dB/km]’ or ‘ZH [dBZ]’. The default is ‘ZH [dBZ]’.
rband: str: Frequency band according to the wavelength of the radar. The string has to be one of ‘C’ or ‘X’. The default is ‘C’.
temp: float: Temperature, in \(^{\circ}C\), used to derive the coefficients according to [1]_. The default is 20.
coeff_a, coeff_b: float: Override the default coefficients of the \(A_H(Z_H)\) relationship. The default are None.
zh_lower_lim, zh_upper_limfloats: Thresholds in \(Z_H\) for the \(A_H(Z_H)\) relationship. Default is \(20 < Z_H < 50 dBZ\).
rhohv_limfloat: Threshold in \(\rho_{HV}\) to filter out invalid values. Default is 0.95.
copy_ofrbool, optional: If True, original values are used to populate out-of-range values, i.e., values below or above zh_limits. The default is True.
data2correctdict, optional: Dictionary that will be updated with the computed variable. The default is None.
plot_methodbool, optional: Plot the \(A_H-Z_H\) relation. The default is False.

Returns#

varsdict

AH [dB/km]:
Specific attenuation at horizontal polarisation.

ZH [dBZ]:
Reflectivity at horizontal polarisation not affected by partial beam blockage, radar miscalibration or the impact of wet radom.

coeff_a, coeff_b:
Interpolated coefficients of the \(A_H(Z_H)\) relation.

Math#

[Eq.1]

\[A_H = aZ_h^b\]

where \(Z_h = 10^{0.1*Z_H}\), \(Z_H\) in dBZ and \(A_H\) in dB/km.

Notes#

Standard values according to [1]_

References#

av_zv(rad_vars, var2calc='ZV [dBZ]', rband='C', temp=10.0, coeff_a=None, coeff_b=None, zv_lower_lim=20.0, zv_upper_lim=50.0, rhohv_lim=0.95, copy_ofr=True, data2correct=None, plot_method=False)[source]#

Compute the \(A_V-Z_V\) relation.

Parameters#

rad_varsdict: Radar object containing at least the specific attenuation \((A_V)\) in dB/km, or the calibrated vertical reflectivity \((Z_V)\) in dBZ, that will be used for calculations.
var2calcstr: Radar variable to be computed. The string has to be one of ‘AV [dB/km]’ or ‘ZV [dBZ]’. The default is ‘ZV [dBZ]’.
rband: str: Frequency band according to the wavelength of the radar. The string has to be one of ‘C’ or ‘X’. The default is ‘C’.
temp: float: Temperature, in \(^{\circ}C\), used to derive the coefficients according to [1]_. The default is 10.
coeff_a, coeff_b: float: Override the default coefficients of the \(A_V(Z_V)\) relationship. The default are None.
zv_lower_lim, zv_upper_limfloats: Thresholds in \(Z_V\) for the \(A_V(Z_V)\) relationship. Default is \(20 < Z_V < 50 dBZ\).
rhohv_limfloat: Threshold in \(\rho_{HV}\) to filter out invalid values. Default is 0.95.
copy_ofrbool, optional: If True, original values are used to populate out-of-range values, i.e., values below or above zv_limits. The default is True.
data2correctdict, optional: Dictionary that will be updated with the computed variable. The default is None.
plot_methodbool, optional: Plot the \(A_V-Z_V\) relation. The default is False.

Returns#

varsdict

AV [dB/km]:
Specific attenuation at vertical polarisation.

ZV [dBZ]:
Reflectivity at vertical polarisation not affected by partial beam blockage, radar miscalibration or the impact of wet radom.

coeff_a, coeff_b:
Interpolated coefficients of the \(A_V(Z_V)\) relation.

Math#

[Eq.1]

\[A_V = aZ_v^b\]

where \(Z_v = 10^{0.1*Z_V}\), \(Z_V\) in dBZ and \(A_V\) in dB/km.

Notes#

Standard values according to [1]_