Abstract
Abstract. The repeat-pass Synthetic Aperture Radio Detection and Ranging (RADAR) Interferometry (InSAR) has been a widely used geodetic technique for observing the Earth’s surface, especially for mapping the Earth’s topography and deformations. However, InSAR measurements are prone to atmospheric errors. RADAR waves traverse the Earth’s atmosphere twice and experience a delay due to atmospheric refraction. The two major layers of the atmosphere (troposphere and ionosphere) are mainly responsible for this delay in the propagating RADAR wave. Previous studies have shown that water vapour and clouds present in the troposphere and the Total Electron Content (TEC) of the ionosphere are responsible for the additional path delay in the RADAR wave. The tropospheric refractivity is mainly dependent on pressure, temperature and partial pressure of water vapour. The tropospheric refractivity leads to an increase in the observed range. These induced propagation delays affect the quality of phase measurement and introduce errors in the topography and deformation fields. The effect of this delay was studied on a differential interferogram (DInSAR). To calculate the amount of tropospheric delay occurred, the meteorological data collected from the Spanish Agencia Estatal de Meteorología (AEMET) and MODIS were used. The interferograms generated from Sentinel-1 carrying C-band Synthetic Aperture RADAR Single Look Complex (SLC) images acquired on the study area are used. The study area consists of different types of scatterers exhibiting different coherence. The existing Saastamoinen model was used to perform a quantitative evaluation of the phase changes caused by pressure, temperature and humidity of the troposphere during the study. Unless the phase values due to atmospheric disturbances are not corrected, it is difficult to obtain accurate measurements. Thus, the atmospheric error correction is essential for all practical applications of DInSAR to avoid inaccurate height and deformation measurements.
Highlights
1.1 Atmospheric Effects on InSARSynthetic Aperture Radio Detection and Ranging (RADAR) (SAR) is an extensive tool to measure the topography of the surface, its changes over time and other changes in the surface (Rosen et al, 2000)
Synthetic Aperture RADAR (SAR) is an extensive tool to measure the topography of the surface, its changes over time and other changes in the surface (Rosen et al, 2000)
Differential Synthetic Aperture RADAR Interferometry or DInSAR is used in remote sensing for measuring Earth surface deformation (Doin et al, 2009)
Summary
Synthetic Aperture RADAR (SAR) is an extensive tool to measure the topography of the surface, its changes over time and other changes in the surface (Rosen et al, 2000). In SAR interferometry, the deformation signal obtained from the Earth surface is mixed with topographic signal (Hanssen, 2001). To overcome this problem, differential interferogram is used. Differential Synthetic Aperture RADAR Interferometry or DInSAR is used in remote sensing for measuring Earth surface deformation (Doin et al, 2009). This technique is considered more accurate than InSAR as it is capable of providing relative measures up to few centimetres or less (Danklmayer et al, 2009). The influence of atmosphere can be a contributing factor for coherence loss (or lack of Persistent Scatterers—PS) and the need to deal with phase ambiguities or wrapped phases (Crosetto et al, 2011)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
