On the Effects of InSAR Temporal Decorrelation and Its Implications for Land Cover Classification: The Case of the Ocean-Reclaimed Lands of the Shanghai Megacity

Abstract

In this work, we focused on the ocean-reclaimed lands of the Shanghai coastal region and we evidenced how, over these areas, the interferometric synthetic aperture radar (InSAR) coherence maps exhibit peculiar behavior. In particular, by analyzing a sequence of Sentinel-1 SAR InSAR coherence maps, we found a significant coherence loss over time in correspondence to the ocean-reclaimed platforms that are substantially different from the coherence loss experienced in naturally-formed regions with the same type of land cover. We have verified whether this is due to the engineering geological conditions or the soil consolidation subsidence in ocean-reclaimed region. In this work, we combine the information coming from InSAR coherence maps and the retrieved temporal decorrelation model with that obtained by using optical Sentinel-2 data, and we performed land cover classification analyses in the zone of the Pudong International Airport. To estimate the accuracy of utilizing InSAR coherence information for land cover classification, in particular, we have analyzed what causes the difference of the InSAR coherence loss with the same type of land cover. The presented results show that the coherence models can be useful to distinguish roads and buildings, thus enhancing the accuracy of land cover classification compared with that allowable by using only Sentinel-2 data. In particular, the accuracy of classification increases from 75% to 86%.

Integrated Analysis of the Combined Risk of Ground Subsidence, Sea Level Rise, and Natural Hazards in Coastal and Delta River Regions

“…The MQQA method has been proposed to combine time overlapped DInSAR deformation time series derived by different SAR instruments. The performance of the MQQA method has been tested by considering the deformation measurements related to five levelling benchmarks, with results supporting [27]).…”

“…Details on this research study and further insights on the achieved results can be found [27]. [27]).…”

“…In particular, proper temporal decorrelation improves the accuracy of land cover classification, with the accuracy value ranging from 75% to 86% in the area of the Pudong international airport (see Figure 3). Details on this research study and further insights on the achieved results can be found [27].…”

“…The principal results of the investigations performed within our Dragon IV project have been published in peer-reviewed journals over the last five years [14][15][16][17][18][19][20][21][22][23][24][25][26][27] and represent the starting point for future studies to be performed in the following years. We will summarize the main results of previous research related to this project in this article.…”

Evaluating the Feasibility of Illegal Open-Pit Mining Identification Using Insar Coherence

“…γ temporal is temporal decorrelation, γ geom is geometric decorrelation, γ vol is the volumetric scattering decorrelation, these three factors matter in our study. Temporal decorrelation is caused by surface changes between SAR acquisitions [48,49]. In this study, the excavation of open-pit mines changes the reflection characteristics of ground objects over a short time period, thereby introducing decorrelation.…”