pyacs.gts.lib.noise.add_vel_sigma module

pyacs.gts.lib.noise.add_vel_sigma.add_vel_sigma(self, b_fn=4, verbose=True)[source]

Estimate velocity uncertainties from residuals (white + flicker noise).

Velocity and residual time series must exist: run detrend(), detrend_annual(), or detrend_seasonal() first. Uncertainty on velocity components (N, E, U) is computed using white noise from the residual scatter and flicker noise (Williams, 2003, eq. 19 and 23). Returns a new Gts with velocity sigmas set.

Parameters:

  • b_fn (float, optional) – Flicker noise parameter in mm/yr^0.25. Default is 4.

  • verbose (bool, optional) – If True, print flicker noise variance. Default is True.

Returns:

New Gts with velocity uncertainties set in velocity[3:6] (m/yr), or None if self.velocity is not set.

Return type:

Gts or None

Notes

White noise is estimated from the first differences of the residual time series. The combined white + flicker sigma is scaled by component RMS so that the minimum component (N, E, or U) keeps the nominal flicker level.

References

Williams, S. D. P. (2003). The effect of coloured noise on the uncertainties of rates from geodetic time series. Journal of Geodesy, 76(9-10), 483-494.