Abstract: A brief review of InSAR atmospheric correction approaches,which have been developed to reduce atmospheric effects(particularly water vapour effects) from SAR interferograms in the last decade,is given.Emphasis is given to GPS topography-dependent turbulence model(GTTM) developed at University College London.Examples over the Los Angeles region reveals that,without InSAR atmospheric correction,the RMS differences between GPS-derived and InSAR-derived range changes in the line of sight(LOS) direction were 1.0 cm.After applying the GTTM,the RMS differences decreased to 0.5 cm,suggesting that the GTTM successfully reduced atmospheric water vapour effects on interferograms.A comparison between the GTTM and the GPS/MODIS integrated water vapour correction model shows that the GTTM and GPS/MODIS integrated models are complementary when correcting InSAR measurements.