where a0 is a constant shift in the model due to interferometric
noise, an and bn are the maximum seasonal amplitude for either
subsidence or uplift oscillations, t and ω are time and angular
frequency of subsidence or uplift oscillation, respectively. For the
seasonal analysis we assumed around 1-year periodicity for initial
parameters for inversion, because the ground deformation (uplift
and subsidence) is based on the annual cycles of discharge and
recharge processes. Some statistical parameters used to evaluate
the fit goodness are sum of squares due to error (SSE), R-square,
and root mean squared error (RMSE).