Working Paper Article Version 2 This version is not peer-reviewed

Quantifying Horizontal and Vertical Movements in Ho Chi Minh City by Sentinel-1 Radar Interferometry

Version 1 : Received: 14 December 2020 / Approved: 15 December 2020 / Online: 15 December 2020 (12:49:12 CET)
Version 2 : Received: 9 September 2021 / Approved: 10 September 2021 / Online: 10 September 2021 (11:04:39 CEST)

How to cite: Ho Tong Minh, D.; NGO, Y.; Lê, T.T.; Le, T.C.; Bui, H.S.; Vuong, Q.V.; Le Toan, T. Quantifying Horizontal and Vertical Movements in Ho Chi Minh City by Sentinel-1 Radar Interferometry. Preprints 2020, 2020120382 Ho Tong Minh, D.; NGO, Y.; Lê, T.T.; Le, T.C.; Bui, H.S.; Vuong, Q.V.; Le Toan, T. Quantifying Horizontal and Vertical Movements in Ho Chi Minh City by Sentinel-1 Radar Interferometry. Preprints 2020, 2020120382

Abstract

Ho Chi Minh City (HCMC), the most crowded city and economic hub of Viet Nam, has been experiencing land subsidence over the past decades. This effort aims to contribute the spatial distribution of subsidence in HCMC in its horizontal and vertical components using synthetic aperture radar interferometry (InSAR) time series. To this purpose, an advanced Persistent Scatterers and Distributed Scatterers (PSDS) InSAR technique was applied to two European Space Agency (ESA) Sentinel-1 datasets consisting of 96 ascending and 202 descending images, acquired from 2014 to 2020 over the HCMC area. A time series of 33 COSMO-SkyMed ascending images was also used for comparison. The combination of ascending and descending satellite passes is used to decompose the light of sight velocities into horizontal east-west and vertical components. Taking into account the presence of east-west horizontal motion, our findings indicate that the accuracy of the decomposed vertical velocity can be improved by up to 3 mm/year for Sentinel-1 data. The obtained results revealed that subsidence is most pronounced in the areas along the Sai Gon River, in the northwest-southeast axis, and in the southwest of the city, with a maximum value of 80 mm/yr, which is in accordance with the findings of the literature. The amplitude of east-west horizontal velocities is relatively small and large-scale eastward movement can be observed in the west of the city at a rate of 3-5 mm/yr. This confirmed that the displacement in Ho Chi Minh City area is mainly vertical downward. Together, these results reinforced the remarkable suitability of ESA's SAR Sentinel-1 for subsidence applications, even for non-European countries such as Vietnam and Southeast Asia.

Supplementary and Associated Material

https://doi.org/10.5281/zenodo.5497723: The obtained velocities freely available for download from Zenodo.

Keywords

Horizontal East-west velocity; LOS; vertical velocity; InSAR time series; Big Data; PSDS; TomoSAR platform; Sentinel-1; Ho Chi Minh City

Comments (1)

Comment 1
Received: 10 September 2021
Commenter: Dinh Ho Tong Minh
Commenter's Conflict of Interests: Author
Comment: The version 2 is improved based on a lot of reviwers's suggestions:
- better color scale horizontal movements,
- fix typos: Cosmo Skymed, Line of sight ,
- better introduction to highlight contributions,
- the obtained velocities freely available for download from Zenodo.   
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