pysteps.extrapolation

Extrapolation module functions and interfaces.

pysteps.extrapolation.interface

The functions in the extrapolation module implement the following interface:

extrapolate(extrap, precip, velocity, num_timesteps,
            outval=np.nan, **keywords)

where extrap is an extrapolator object returned by the initialize function, precip is a (m,n) array with input precipitation field to be advected and velocity is a (2,m,n) array containing the x- and y-components of the m x n advection field. num_timesteps is an integer specifying the number of time steps to extrapolate. The optional argument outval specifies the value for pixels advected from outside the domain. Optional keyword arguments that are specific to a given extrapolation method are passed as a dictionary.

The output of each method is an array R_e that includes the time series of extrapolated fields of shape (num_timesteps, m, n).

get_method(name) Return two-element tuple for the extrapolation method corresponding to the given name.
eulerian_persistence(precip, velocity, …) A dummy extrapolation method to apply Eulerian persistence to a two-dimensional precipitation field.

pysteps.extrapolation.semilagrangian

Implementation of the semi-Lagrangian method of Germann et al (2002). [GZ02]

extrapolate(precip, velocity, num_timesteps) Apply semi-Lagrangian extrapolation to a two-dimensional precipitation field.