A New Method for Determining Surface Deformation and Tropospheric Noise Characteristics from Interferogram Subsets

Abstract

Interferometric Synthetic Aperture Radar (InSAR) surface deformation estimates often suffer from tropospheric noise errors. Here we present a method for co-characterizing surface deformation and tropospheric noise from interferogram subsets. Choosing different subsets of all available interferograms allow identification of linear secular deformation, little apparent deformation, transient events, or higher order nonlinear rates. We demonstrate this method using 95 C-Band Sentinel-1 SAR scenes acquired over the Oman Ophiolite and 133 scenes over the Island of Hawaii. In Oman, our method suggests that there is no detectable deformation signal. In this scenario, we averaged subsets of randomly selected interferograms that share a common reference SAR scene. As the subset size increases, at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 50$</tex> , the results converge to accurate estimates of tropospheric noise on the reference date. In Hawaii, our method shows that the observed InSAR phase on the south flank of Kilauea is due to a secular deformation signal, while the phase over Mauna Loa is mostly associated with tropospheric noise. Our approach provides a new way to derive InSAR uncertainty analyses without requiring additional in situ validation or prior knowledge of deformation models.