pysteps.verification.salscores.sal(prediction, observation, thr_factor=0.067, thr_quantile=0.95, tstorm_kwargs=None)#

Compute the Structure-Amplitude-Location (SAL) spatial verification metric.

  • prediction (array-like) – Array of shape (m,n) with prediction data. NaNs are ignored.

  • observation (array-like) – Array of shape (m,n) with observation data. NaNs are ignored.

  • thr_factor (float, optional) – Factor used to compute the detection threshold as in eq. 1 of [WHZ09]. If not None, this is used to identify coherent objects enclosed by the threshold contour thr_factor * thr_quantile(precip).

  • thr_quantile (float, optional) – The wet quantile between 0 and 1 used to define the detection threshold. Required if thr_factor is not None.

  • tstorm_kwargs (dict, optional) – Optional dictionary containing keyword arguments for the tstorm feature detection algorithm. If None, default values are used. See the documentation of pysteps.feature.tstorm.detection().


sal – A 3-element tuple containing the structure, amplitude, location components of the SAL score.

Return type:

tuple of floats


[WPHF08] [WHZ09] [FGGB21]


This implementation uses the thunderstorm detection algorithm by [FGGB21] for the identification of precipitation objects within the considered domain.