Abstract. Interferometric Synthetic Aperture Radar (InSAR) is a powerful tool for detecting ground deformation with millimeter precision. However, atmospheric effects, particularly tropospheric delays, significantly degrade the accuracy of InSAR-derived measurements. This study investigates elevation-dependent errors in tropospheric delay interpolation using Global Navigation Satellite System (GNSS)-derived Zenith Tropospheric Delay (ZTD) data. Two GNSS networks with similar spatial configurations but different elevation characteristics were analyzed to quantify the effect of altitude differences on interpolation accuracy. A novel correction method was proposed to mitigate the elevation-induced bias by isolating and modifying the dry component of the ZTD using the Saastamoinen model. Results demonstrate that this approach substantially improves interpolation accuracy up to 92% enhancement in high-relief areas. The findings highlight the critical importance of considering elevation effects when integrating GNSS and InSAR data for atmospheric delay correction, especially in mountainous regions.
Chaharmahali et al. (Sat,) studied this question.