Tracking of Land Reclamation Activities Using Landsat Observations—An Example in Shanghai and Hangzhou Bay

Abstract

At present, reclamation—changing ocean areas into inland land cover type for human usage—is one of the major methods for expanding land area around the world to alleviate the problem of land shortage. Thus, reclamation activities play an important role in land area extension. In recent years, reclamation projects have been active in eastern China. However, research on how to determine the initiation of reclamation activity remains very limited. Thus, a method of tracking reclamation activities was proposed in this study to analyze the coastline change due to human activities in Shanghai Lingang New City and Hangzhou Bay area. First, the reclamation area was extracted and separated into sea filling and sea enclosing. Next, the “SEDIMENT” signal track method and the “Eight-Neighborhood” morphological method were used to track dissimilar reclamation types. The historical reclamation activities (including start time and end time) over the recent 30 years were also tracked and obtained. Experimental results indicated that the time tracker accuracy of reclamation activity can reach 83.8%. Thus, this study can provide a reference for tracking coastline change.

Remote Sensing Observations of a Coastal Water Environment Based on Neural Network and Spatiotemporal Fusion Technology: A Case Study of Hangzhou Bay

“…In comparison to natural impacts, human activities often exert more intense and complex influences on the water color and morphological characteristics. For example, bridge construction projects can significantly alter SPM concentrations over several kilometers [27], while deposit-promoting projects swiftly change landcover types [28], affecting nearby erosion-deposition patterns, as well as SPM distribution. Figure 1 shows three regions of interest within Hangzhou Bay, as follows: A.1 was selected to assess the observational capabilities for SPM distributions.…”

Observations of the Impacts of Hong Kong International Airport on Water Quality from 1986 to 2022 Using Landsat Satellite

“…To address the lack of available land, one of the critical methods of increasing land area in many countries is reclamation, which involves converting open ocean areas into inland areas for human use. In modern society, there is an increase in nearshore and offshore engineering [3][4][5][6][7], which inevitably pollutes the marine environment and influences water quality, for example, in terms of suspended particulate matter (SPM), orthophosphate phosphorus (PO 4 P), and dissolved inorganic nitrogen (DIN), especially SPM [8][9][10]. Driven by wind, waves, and ocean currents, SPM and nutrient salts continuously drift and spread, posing a serious threat to the marine ecological balance [11][12][13][14][15].…”

“…GF-1 WFV has a high spatial resolution (16 m), but short time series (from 2013 to now) [12]. Landsat satellites have the proper image width (185 km), spatial resolution (30 m), and time series (from 1972 to now) [3,31,38]. Previous studies have demonstrated the feasibility of using Landsat satellites to observe water quality changes in the Pearl River Estuary region [10,16,20,33].…”