Map of mean annual rate of range change in the observed (a), modelled (b) and final residual (c, next page) fields. The observed values have been unwrapped using the final model. They have also been corrected for tropospheric effects by subtracting the value of the nuisance functions calculated with the final estimate of the tropospheric parameters. Contours are in mm yr⁻¹. Downward subsidence appears as a positive rate of range change.