Data Transformation#
Module <trafo> transforms data e.g. from RVP-units to dBZ-values to Z-values and vice versa.
Calculates dBZ-values from DWD RVP6 values as given in DX-product files. |
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Calculates the decibel representation of the input values |
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Calculates the inverse of input decibel values |
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Computes rainfall depth (mm) from rainfall intensity (mm/h) |
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Estimating rainfall intensity directly from specific differential phase. |
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Conversion from SI wind speed units to km/hr. |
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Conversion from SI wind speed units to miles/hr |
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Conversion from SI wind speed units to knots |
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Conversion from km/hr to SI wind speed units |
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Conversion from miles/hr to SI wind speed units |
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Conversion from knots to SI wind speed units |
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Class to hold coefficients for Radar Reflectivity Conversion |
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Class to hold coefficients for Radar Reflectivity Conversion |
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Class to hold coefficients for Radar Reflectivity Conversion |
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wradlib xarray SubAccessor methods for DualPol. |
- wradlib.trafo.rvp_to_dbz(x)[source]#
Calculates dBZ-values from DWD RVP6 values as given in DX-product files.
- Parameters
x (
float
ornumpy.ndarray
) – a number or an array
Examples
>>> from wradlib.trafo import rvp_to_dbz >>> print(rvp_to_dbz(65.)) 0.0
- wradlib.trafo.decibel(x)[source]#
Calculates the decibel representation of the input values
\(dBZ=10 \cdot \log_{10} z\)
- Parameters
x (
float
ornumpy.ndarray
) – (must not be <= 0.)
Examples
>>> from wradlib.trafo import decibel >>> print(decibel(100.)) 20.0
- wradlib.trafo.idecibel(x)[source]#
Calculates the inverse of input decibel values
\(z=10^{x \over 10}\)
- Parameters
x (
float
ornumpy.ndarray
)
Examples
>>> from wradlib.trafo import idecibel >>> print(idecibel(10.)) 10.0
- wradlib.trafo.r_to_depth(x, interval)[source]#
Computes rainfall depth (mm) from rainfall intensity (mm/h)
- Parameters
x (
float
ornumpy.ndarray
) – rainfall intensity in mm/hinterval (
float
) – time interval (s) the values of x represent
- Returns
output (
float
ornumpy.ndarray
) – rainfall depth (mm)
- wradlib.trafo.kdp_to_r(kdp, f, a=129.0, b=0.85)[source]#
Estimating rainfall intensity directly from specific differential phase.
The general power law expression has been suggested by [Ryzhkov et al., 2005].
The default parameters have been set according to [Bringi et al., 2001].
Note
Please note that this way, rainfall intensities can become negative. This is an intended behaviour in order to account for noisy \(K_{DP}\) values.
- Parameters
kdp (
float
ornumpy.ndarray
) – \(K_{DP}\) as array of floatsf (
float
) – radar frequency [GHz]Standard frequencies in X-band range between 8.0 and 12.0 GHz,
Standard frequencies in C-band range between 4.0 and 8.0 GHz,
Standard frequencies in S-band range between 2.0 and 4.0 GHz.
a (
float
) – linear coefficient of the power lawb (
float
) – exponent of the power law
- Returns
output (
numpy.ndarray
) – array of rainfall intensity
- wradlib.trafo.si_to_kmh(vals)[source]#
Conversion from SI wind speed units to km/hr.
Note
Code was migrated from nguy/PyRadarMet.
- Parameters
vals (
float
ornumpy.ndarray
) – Speed in SI units (m/s)- Returns
output (
float
ornumpy.ndarray
) – Speed in km/hr
Examples
>>> from wradlib.trafo import si_to_kmh >>> print(si_to_kmh(1.)) 3.6
- wradlib.trafo.si_to_mph(vals)[source]#
Conversion from SI wind speed units to miles/hr
Note
Code was migrated from nguy/PyRadarMet.
- Parameters
vals (
float
ornumpy.ndarray
) – Speed in SI units (m/s)- Returns
output (
float
ornumpy.ndarray
) – Speed in miles per hour
Examples
>>> from wradlib.trafo import si_to_mph >>> print(np.round(si_to_mph(1.), 3)) 2.237
- wradlib.trafo.si_to_kts(vals)[source]#
Conversion from SI wind speed units to knots
Note
Code was migrated from nguy/PyRadarMet.
- Parameters
vals (
float
ornumpy.ndarray
) – Speed in SI units (m/s)- Returns
output (
float
ornumpy.ndarray
) – Speed in knots
Examples
>>> from wradlib.trafo import si_to_kts >>> print(np.round(si_to_kts(1.), 3)) 1.944
- wradlib.trafo.kmh_to_si(vals)[source]#
Conversion from km/hr to SI wind speed units
Note
Code was migrated from nguy/PyRadarMet.
- Parameters
vals (
float
ornumpy.ndarray
) – Wind speed in km/hr- Returns
output (
float
ornumpy.ndarray
) – Wind speed in SI units (m/s)
Examples
>>> from wradlib.trafo import kmh_to_si >>> print(np.round(kmh_to_si(10.), 3)) 2.778
- wradlib.trafo.mph_to_si(vals)[source]#
Conversion from miles/hr to SI wind speed units
Note
Code was migrated from nguy/PyRadarMet.
- Parameters
vals (
float
ornumpy.ndarray
) – Wind speed in miles per hour- Returns
output (
float
ornumpy.ndarray
) – Wind speed in SI units (m/s)
Examples
>>> from wradlib.trafo import mph_to_si >>> print(np.round(mph_to_si(10.), 2)) 4.47
- wradlib.trafo.kts_to_si(vals)[source]#
Conversion from knots to SI wind speed units
Note
Code was migrated from nguy/PyRadarMet.
- Parameters
vals (
float
ornumpy.ndarray
) – Wind speed in knots- Returns
output (
float
ornumpy.ndarray
) – Wind speed in SI units (m/s)
Examples
>>> from wradlib.trafo import kts_to_si >>> print(np.round(kts_to_si(1.), 3)) 0.514
- class wradlib.trafo.KuBandToS[source]#
Bases:
object
Class to hold coefficients for Radar Reflectivity Conversion
From Ku-band (13.8 GHz) to S-band (2.8 GHz)
See [Cao et al., 2013] for reference.
- snow = array([[ 4.78e-02, 4.12e-02, 8.12e-02, 1.59e-01, 2.87e-01, 4.93e-01, 8.16e-01, 1.31e+00, 2.01e+00, 2.82e+00, 1.74e-01], [ 1.23e-02, 3.66e-03, 2.00e-03, 9.42e-04, 5.29e-04, 5.96e-04, 1.22e-03, 2.11e-03, 3.34e-03, 5.33e-03, 1.35e-02], [-3.50e-04, 1.17e-03, 1.04e-03, 8.16e-04, 6.59e-04, 5.85e-04, 6.13e-04, 7.01e-04, 8.24e-04, 1.01e-03, -1.38e-03], [-3.30e-05, -8.08e-05, -6.44e-05, -4.97e-05, -4.15e-05, -3.89e-05, -4.15e-05, -4.58e-05, -5.06e-05, -5.78e-05, 4.74e-05], [ 4.27e-07, 9.25e-07, 7.41e-07, 6.13e-07, 5.80e-07, 6.16e-07, 7.12e-07, 8.22e-07, 9.39e-07, 1.10e-06, 0.00e+00]])#
- hail = array([[ 4.78e-02, 1.80e-01, 1.95e-01, 1.88e-01, 2.36e-01, 2.70e-01, 2.98e-01, 2.85e-01, 1.75e-01, 4.30e-02, 8.80e-02], [ 1.23e-02, -3.73e-02, -3.83e-02, -3.29e-02, -3.46e-02, -2.94e-02, -2.10e-02, -9.96e-03, -8.05e-03, -8.27e-03, 5.39e-02], [-3.50e-04, 4.08e-03, 4.14e-03, 3.75e-03, 3.71e-03, 3.22e-03, 2.44e-03, 1.45e-03, 1.21e-03, 1.66e-03, -2.99e-04], [-3.30e-05, -1.59e-04, -1.54e-04, -1.39e-04, -1.30e-04, -1.12e-04, -8.56e-05, -5.33e-05, -4.66e-05, -7.19e-05, 1.90e-05], [ 4.27e-07, 1.59e-06, 1.51e-06, 1.37e-06, 1.29e-06, 1.15e-06, 9.40e-07, 6.71e-07, 6.33e-07, 9.52e-07, 0.00e+00]])#
- class wradlib.trafo.KuBandToX[source]#
Bases:
object
Class to hold coefficients for Radar Reflectivity Conversion
From Ku-band (13.8 GHz) to X-band (9.4 GHz)
See [Pejcic et al., 2022] for reference.
- snow = array([[ 1.91e-01, -1.20e-01], [-7.83e-02, 6.80e-02], [ 1.12e-02, -4.55e-03], [-6.17e-04, 1.18e-04], [ 1.25e-05, -6.60e-07], [-8.43e-08, 0.00e+00]])#
- hail = array([[ 1.91e-01, 5.57e-02], [-7.83e-02, 1.80e-02], [ 1.12e-02, 1.91e-03], [-6.17e-04, -6.64e-05], [ 1.25e-05, 8.18e-07], [-8.43e-08, 0.00e+00]])#
- class wradlib.trafo.SBandToKu[source]#
Bases:
object
Class to hold coefficients for Radar Reflectivity Conversion
From S-band (2.8GHz) to Ku-band (13.8GHz)
See [Liao et al., 2009] for reference.
- snow = array([ 0.185074 , 1.01378 , -0.00189212])#
- rain = array([-1.50393e+00, 1.07274e+00, 1.65393e-04])#
- class wradlib.trafo.TrafoMethods(obj)[source]#
Bases:
XarrayMethods
wradlib xarray SubAccessor methods for DualPol.
- decibel()[source]#
Calculates the decibel representation of the input values
\(dBZ=10 \cdot \log_{10} z\)
- Parameters
x (
float
ornumpy.ndarray
) – (must not be <= 0.)
Examples
>>> from wradlib.trafo import decibel >>> print(decibel(100.)) 20.0
- idecibel()[source]#
Calculates the inverse of input decibel values
\(z=10^{x \over 10}\)
- Parameters
x (
float
ornumpy.ndarray
)
Examples
>>> from wradlib.trafo import idecibel >>> print(idecibel(10.)) 10.0
- r_to_depth(interval)[source]#
Computes rainfall depth (mm) from rainfall intensity (mm/h)
- Parameters
x (
float
ornumpy.ndarray
) – rainfall intensity in mm/hinterval (
float
) – time interval (s) the values of x represent
- Returns
output (
float
ornumpy.ndarray
) – rainfall depth (mm)