Atmospheric Effects on InSAR Measurements and Their Mitigation

Abstract

Interferometric Synthetic Aperture Radar (InSAR) is a powerful technology for observing the Earth surface, especially for mapping the Earth's topography and deformations. InSAR measurements are however often significantly affected by the atmosphere as the radar signals propagate through the atmosphere whose state varies both in space and in time. Great efforts have been made in recent years to better understand the properties of the atmospheric effects and to develop methods for mitigating the effects. This paper provides a systematic review of the work carried out in this area. The basic principles of atmospheric effects on repeat-pass InSAR are first introduced. The studies on the properties of the atmospheric effects, including the magnitudes of the effects determined in the various parts of the world, the spectra of the atmospheric effects, the isotropic properties and the statistical distributions of the effects, are then discussed. The various methods developed for mitigating the atmospheric effects are then reviewed, including the methods that are based on PSInSAR processing, the methods that are based on interferogram modeling, and those that are based on external data such as GPS observations, ground meteorological data, and satellite data including those from the MODIS and MERIS. Two examples that use MODIS and MERIS data respectively to calibrate atmospheric effects on InSAR are also given.

Staring Spotlight TerraSAR-X SAR Interferometry for Identification and Monitoring of Small-Scale Landslide Deformation

“…The aforementioned geological features, along with the historical landslide in the Hope Slide, draws attention to using the TSX-ST images to perform a comprehensive analysis of slope stability on and around Hope Slide, to better understand the triggers and dynamics of mass movements in the area. Due to the topography of the area, the Hope Slide is exposed to strong turbulent mixing processes, atmospheric stratification, and changes in atmospheric pressure in time, which introduce significant atmospheric errors to these high resolution TSX-ST images [12]. Addressing and modelling the atmospheric effect (e.g., by means of the methodology described in Sections 3.1 and 3.2) plays a key role in retrieving the deformation phase from the TSX-ST acquisitions for the Hope Slide.…”

Recent Trend and Advance of Synthetic Aperture Radar with Selected Topics

“…If microwave pulses pass through locally dense vapor in the troposphere, there appears a time delay caused by the vapor, and the path difference becomes ∆R + ∆R T where ∆R T is the path difference corresponding to this time delay [610,611]. The path difference ∆R T may be as large as tens of centimeters in spatial scale [608], and therefore, the interferometric phase corresponding to this delay causes erroneous measurements of surface topography or deformation [612,613]. It is common to separate the tropospheric delays into two components: one related to turbulent mixing processes and the other related to tropospheric stratification.…”

“…It was also suggested that the removal of the atmospheric effects before phase unwrapping reduces the errors in phase unwrapping in the areas of high relief [628]. For further details, see a good review article on the issue of atmospheric effects and their mitigation [612,613].…”

Short Baseline TerraSAR-X PSI for Monitoring Subsidence of Highways and Railways, Case Study with Corner Reflectors

“…The InSAR technique has excellent ability to reveal spatial pattern of the subsidence in more detail. However, InSAR technique is inevitably affected by spatiotemporal decorrelation [7] and atmospheric delay [8], which significantly reduce the accuracy of InSAR measurements. To overcome such drawbacks, Ferretti et al proposed the persistent scatterer interferometry (PSI) method in 2001 [9].…”