ppcpy.retrievals.quasi#

Functions

detect_liquid_bits

detect liquid cloud bits.

quasi_angstrom

quasi_pdr

target_cat

target_classify

aerosol/cloud target classification.
ppcpy.retrievals.quasi.quasi_pdr(data_cube, wvs=[532], version='V1')[source]#
ppcpy.retrievals.quasi.quasi_angstrom(data_cube, version='V1')[source]#
ppcpy.retrievals.quasi.target_cat(data_cube, version='V1')[source]#
ppcpy.retrievals.quasi.target_classify(height, attBeta532, quasiBsc1064, quasiBsc532, quasiPDR532, VDR532, quasiAE, **kwargs)[source]#

aerosol/cloud target classification.

Parameters:

  • height (ndarray) – Height array (m).

  • attBeta532 (ndarray) – Attenuated backscatter at 532 nm.

  • quasiBsc1064 (ndarray) – Quasi particle backscatter at 1064 nm. (m^{-1}sr^{-1})

  • quasiBsc532 (ndarray) – Quasi particle backscatter at 532 nm. (m^{-1}sr^{-1})

  • quasiPDR532 (ndarray) – Quasi particle depolarization ratio at 532 nm.

  • VDR532 (ndarray) – Volume depolarization ratio at 532 nm.

  • quasiAE (ndarray) – Quasi Ångström exponents.

  • **kwargs – Optional parameters to control thresholds.

Keyword Arguments:

  • clearThresBsc1064 (float) – Default 1e-8.

  • turbidThresBsc1064 (float) – Default 2e-7.

  • turbidThresBsc532 (float) – Default 2e-7.

  • dropletThresPDR (float) – Default 0.05.

  • spheriodThresPDR (float) – Default 0.07.

  • unspheroidThresPDR (float) – Default 0.2.

  • iceThresVDR (float) – Default 0.3.

  • iceThresPDR (float) – Default 0.35.

  • largeThresAE (float) – Default 0.75.

  • smallThresAE (float) – Default 0.5.

  • cloudThresBsc1064 (float) – Default 2e-5.

  • minAttnRatioBsc1064 (float) – Default 10.

  • searchCloudAbove (float) – Default 300.

  • searchCloudBelow (float) – Default 100.

  • hFullOL (float) – Default 600.

Returns:

Classification mask.

0: No signal 1: Clean atmosphere 2: Non-typed particles/low conc. 3: Aerosol: small 4: Aerosol: large, spherical 5: Aerosol: mixture, partly non-spherical 6: Aerosol: large, non-spherical 7: Cloud: non-typed 8: Cloud: water droplets 9: Cloud: likely water droplets 10: Cloud: ice crystals 11: Cloud: likely ice crystal

Return type:

ndarray

References

Baars, H., Seifert, P., Engelmann, R. & Wandinger, U. Target categorization of aerosol and clouds by continuous multiwavelength-polarization lidar measurements. Atmospheric Measurement Techniques 10, 3175-3201, doi:10.5194/amt-10-3175-2017 (2017).

History:

  • 2021-06-05: First edition by Zhenping

  • 2025-03-25: AI based translation to python

ppcpy.retrievals.quasi.detect_liquid_bits(height, bsc1064, cloudThresBsc1064=2e-05, minAttnRatioBsc1064=10, searchCloudAbove=300, searchCloudBelow=100, **kwargs)[source]#

detect liquid cloud bits.

Parameters:

  • height (ndarray) – Height array (m).

  • bsc1064 (ndarray) – Particle backscatter at 1064 nm (height x time).

  • cloudThresBsc1064 (float, optional) – Threshold of cloud backscatter at 1064 nm. Default is 2e-5.

  • minAttnRatioBsc1064 (float, optional) – Minimum attenuation required to detect liquid cloud. Default is 10.

  • searchCloudAbove (float, optional) – Cloud search window above current bit (m). Default is 300.

  • searchCloudBelow (float, optional) – Cloud search window below current bit (m). Default is 100.

Returns:

Logical mask (height x time) for detected liquid cloud regions.

Return type:

ndarray

History:

  • 2021-06-05: First edition by Zhenping

  • 2025-03-25: AI based translation to python