LiCSBAS: An Open-Source InSAR Time Series Analysis Package Integrated with the LiCSAR Automated Sentinel-1 InSAR Processor

Abstract

For the past five years, the 2-satellite Sentinel-1 constellation has provided abundant and useful Synthetic Aperture Radar (SAR) data, which have the potential to reveal global ground surface deformation at high spatial and temporal resolutions. However, for most users, fully exploiting the large amount of associated data is challenging, especially over wide areas. To help address this challenge, we have developed LiCSBAS, an open-source SAR interferometry (InSAR) time series analysis package that integrates with the automated Sentinel-1 InSAR processor (LiCSAR). LiCSBAS utilizes freely available LiCSAR products, and users can save processing time and disk space while obtaining the results of InSAR time series analysis. In the LiCSBAS processing scheme, interferograms with many unwrapping errors are automatically identified by loop closure and removed. Reliable time series and velocities are derived with the aid of masking using several noise indices. The easy implementation of atmospheric corrections to reduce noise is achieved with the Generic Atmospheric Correction Online Service for InSAR (GACOS). Using case studies in southern Tohoku and the Echigo Plain, Japan, we demonstrate that LiCSBAS applied to LiCSAR products can detect both large-scale (>100 km) and localized (~km) relative displacements with an accuracy of <1 cm/epoch and ~2 mm/yr. We detect displacements with different temporal characteristics, including linear, periodic, and episodic, in Niigata, Ojiya, and Sanjo City, respectively. LiCSBAS and LiCSAR products facilitate greater exploitation of globally available and abundant SAR datasets and enhance their applications for scientific research and societal benefit.

Displacements Monitoring over Czechia by IT4S1 System for Automatised Interferometric Measurements Using Sentinel-1 Data

“…It allows for an easy and effective inclusion of various MT-InSAR algorithms. The system is already capable of PS and SB through STAMPS [23] and SALSIT [20], as well as (experimentally) NSBAS time series through LiCSBAS [26]. A working MATLAB software is a prerequisite for IT4S1, as only a part of STAMPS scripts can be run through Octave directly.…”

“…Additionally, the data generated for STAMPS processing were optionally used for reprocessing using other algorithms implemented within the system-an octave-based SALSIT PS software [20] and a python-based LiCSBAS software [26]. These tools were considered complementary at the moment and are not included to the automatic processing chain (they are briefly discussed in the following subsections).…”

“…We have recently implemented LiCSBAS software [26] to IT4S1. This tool uses unwrapped interferograms into a specific NSBAS time series inversion [30].…”

“…Additionally, we also include a preview of the output by LiCSBAS algorithm [26] applied to the same graph of SB connections, in Figure 8c. Here, we estimate LOS velocity rates over all unwrapped pixels in the area, including densely vegetated areas (covering most of the scene).…”

Postseismic Deformation Following the 2016 Kumamoto Earthquake Detected by ALOS-2/PALSAR-2

“…Recently Sentinel-1 images are being used to study crustal deformation because its recurrence is 6 or 12 days and large amount of image of the same area have been already accumulated. However, temporal decorrelation is strong especially in vegetated area [e.g Morishita et al, 2020],. and it is difficult to obtain deformation with a single pair of images with long temporal separation.…”