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Generic atmospheric correction model for Interferometric Synthetic Aperture Radar observations

Lookup NU author(s): Chen Yu, Professor Zhenhong Li, Dr Nigel Penna, Dr Paola Crippa

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This is the final published version of an article that has been published in its final definitive form by Wiley-Blackwell Publishing, Inc., 2018.

For re-use rights please refer to the publisher's terms and conditions.


Abstract

For mapping Earth surface movements at larger scale and smaller amplitudes, many new Synthetic Aperture Radar (SAR) instruments (Sentinel-1A/B, Gaofen-3, ALOS-2) have been developed and launched from 2014-2017, and this trend is set to continue with Sentinel-1C/D, Gaofen-3B/C, RADARSAT Constellation planned for launch during 2018-2025. This poses more challenges for correcting interferograms for atmospheric effects since the spatial-temporal variations of tropospheric delay may dominate over large scales and completely mask the actual displacements due to tectonic or volcanic deformation. To overcome this, we have developed a generic InSAR atmospheric correction model whose notable features comprise: (i) global coverage, (ii) all-weather, all-time useability, (iii) correction maps available in near real-time, and (iv) indicators to assess the correction performance and feasibility. The model integrates operational high-resolution ECMWF data (0.125-degree grid, 137 vertical levels, 6-hour interval) and continuous GPS tropospheric delay estimates (every 5 minutes) using an iterative tropospheric decomposition model. The model’s performance was tested using eight globally-distributed Sentinel-1 interferograms, encompassing both flat and mountainoustopographies, mid-latitude and near polar regions, monsoon and oceanic climate systems, achieving a phase standard deviation and displacement RMS of ~1 cm against GPS over wide regions (250 by 250 km). Indicators describing the model’s performance including (i) GPS network and ECMWF cross-RMS, (ii) phase versus estimated atmospheric delay correlations, (iii) ECMWF time differences, and (iv) topography variations, were developed to provide quality control for subsequent automatic processing, and provide insights of the confidence level with which the generated atmospheric correction maps may be applied.


Publication metadata

Author(s): Yu C, Li Z, Penna NT, Crippa P

Publication type: Article

Publication status: Published

Journal: Journal of Geophysical Research - Solid Earth

Year: 2018

Volume: 123

Issue: 10

Pages: 9202-9222

Print publication date: 01/10/2018

Online publication date: 12/09/2018

Acceptance date: 07/09/2018

Date deposited: 08/09/2018

ISSN (print): 2169-9313

ISSN (electronic): 2169-9356

Publisher: Wiley-Blackwell Publishing, Inc.

URL: https://doi.org/10.1029/2017JB015305

DOI: 10.1029/2017JB015305


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