wradlib.qual.QualMethods.estimate_snr

wradlib.qual.QualMethods.estimate_snr#

QualMethods.estimate_snr(rng, noise_level, gas_att)[source]#

Estimate radar signal-to-noise ratio (SNR) from reflectivity.

This function reconstructs the radar SNR in dB space using reflectivity, range-dependent geometric spreading loss, receiver noise level, and gaseous attenuation.

The formulation follows standard radar equation scaling, where reflectivity is converted into a received signal proxy and corrected for range and propagation losses.

Parameters:

  • dbz (array_like) – Equivalent radar reflectivity factor in dBZ.

  • rng (array_like) – Range from radar in meters (m).

  • noise_level (float or array_like) – Receiver noise level expressed in dB (consistent with dbz scaling).

  • gas_att (float) – Effective gaseous attenuation coefficient in dB/km. This parameter represents a two-way radar-path attenuation (i.e. round-trip effective loss).

Returns:

snr (array_like) – Estimated signal-to-noise ratio in dB.

Notes

The SNR is computed as:

SNR = dbz - 20 * log10(rng_km) - noise_level - gas_att * rng_km

where: - 20 * log10(rng) represents two-way geometric spreading loss - gas_att is an effective attenuation coefficient (dB/km),

typically including round-trip propagation effects

  • noise_level represents receiver noise in dB

References

[Doviak et al., 1993], [Bringi et al., 2001], [ITU, 2021]