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Coastal Environments and Coastal Hazards

A special issue of Remote Sensing (ISSN 2072-4292). This special issue belongs to the section "Biogeosciences Remote Sensing".

Deadline for manuscript submissions: closed (30 November 2021) | Viewed by 47826

Special Issue Editors


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Guest Editor
School of Marine Sciences, Nanjing University of Information Science and Technology, 219 Road Ninglu, Pukou District, Nanjing 210044, China
Interests: remote sensing of water quality; coastal environments and hazards; sea ice and snow
Special Issues, Collections and Topics in MDPI journals

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Guest Editor

E-Mail Website
Guest Editor
State Key Laboratory of Resources and Environmental Information Systems, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Datun Road, Beijing 100101, China
Interests: coastal remote sensing and GIS; monitoring and assessment; coastal hazards and resilience
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
College of Oceanography and Space Informatics, China University of Petroleum (Eastern China), No. 66 West Changjiang Road, Huangdao District, Qingdao 266580, China
Interests: coastal environmental remote sensing; coastal ocean waves; buoy observations; storm and typhoon impacts

Special Issue Information

Dear Colleagues,

In many coastal regions, rapid industrial, urban, and agricultural development has caused dramatic land use and land cover (LULC) changes and various water pollution events in coastal environments. These environmental consequences by human activities exacerbate the effects of regional and global climate change on the hydrological cycle between the land and ocean, and these effects are frequently hazardous or destructive to coastal regions around the world.

Coastal hazards are physical phenomena that expose a coastal area to risks such as property damage, loss of life, and environmental degradation. One type of induced coastal hazards has a rapid onset and may last for a few minutes to several days, including major cyclones accompanied by high winds as well as storm surges or tsunamis that are created by submarine earthquakes or landslides. The other is slow-onset hazards that develop incrementally over a longer time period, such as erosion and gradual inundation.

This Special Issue will foster an informed debate among scientists and stakeholders on the coastal environment subject to the influence of coastal hazards and global climate change. The theme of this Special Issue mainly includes studies on coastal eco-environmental quality, sea-level rise, coastal erosion, and other coastal ocean hazards and their integrative effects that are based on in situ and remote observations, including space-, aerial-, drone-, buoy- or laboratory-based measurements.

Due to their great relevance to the proposed theme as well as the interest of a broad audience, this Special Issue is inviting manuscripts on the following topics:

  • Air–sea interaction and landfall storms;
  • Aquatic ecosystems’ feedback to and interactions with climate change;
  • Climate and anthropogenic influence on coastal water quality and adjacent ecosystems, including wetlands and coral reefs;
  • Coastal erosion, estuarine sustainment, and impacts of LULC changes;
  • Coastal geomorphology, landscape structure change, and geological hazards;
  • Coastal ocean hazards: monitoring and assessment with GPS, GIS, and remote sensing;
  • Coastal ocean hazards: algorithms and observation methods;
  • Coastal urbanization, coastal infrastructure, and coastal engineering on coastal environments
  • Coastal ocean waves and typhoon impacts: data modeling;
  • Coastal remote sensing by integrating remotely sensed data with in situ measurements;
  • Coastal, estuarine, and adjacent inland waters: color, quality, and optical properties

Prof. Dr. Yuanzhi Zhang
Prof. Dr. Lin Li
Prof. Dr. Shengbo Chen
Prof. Dr. Xiaomei Yang
Prof. Dr. Sun Genyun
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Remote Sensing is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • coastal environments
  • coastal erosion
  • coastal geological hazards
  • coastal geomorphology and landscape structure
  • coastal hazards and assessment
  • coastal and urban infrastructure
  • coastal ocean waves and storms
  • coastal remote sensing
  • estuarine–coastal ecosystems
  • sea-level rise
  • typhoons and their impacts
  • water quality
  • water pollution

Published Papers (16 papers)

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Research

21 pages, 80554 KiB  
Article
Variability of Chlorophyll-a and Secchi Disk Depth (1997–2019) in the Bohai Sea Based on Monthly Cloud-Free Satellite Data Reconstructions
by Junting Guo, Jingfang Lu, Yuming Zhang, Chen Zhou, Shufang Zhang, Daosheng Wang and Xianqing Lv
Remote Sens. 2022, 14(3), 639; https://doi.org/10.3390/rs14030639 - 28 Jan 2022
Cited by 12 | Viewed by 2978
Abstract
Ocean colour data are crucial for monitoring and assessing marine ecosystems. In this study, the Data Interpolating Empirical Orthogonal Functions (DINEOF) approach was applied to the Ocean Colour Climate Change Initiative (OC-CCI), chlorophyll-a (Chl-a) and Secchi disk depth (Zsd) to completely [...] Read more.
Ocean colour data are crucial for monitoring and assessing marine ecosystems. In this study, the Data Interpolating Empirical Orthogonal Functions (DINEOF) approach was applied to the Ocean Colour Climate Change Initiative (OC-CCI), chlorophyll-a (Chl-a) and Secchi disk depth (Zsd) to completely reconstruct the missing pixels in the Bohai Sea during 1997–2019. The results of cross-validation demonstrate that the DINEOF reconstructed data have a good agreement with the satellite-measured data. Based on monthly cloud-free satellite data reconstructions, the Zsd series showed high negative correlation with log10 (Chl-a). The Zsd as a function of log10 (Chl-a) can be well fitted by the cubic polynomial in the offshore waters. The Chl-a in the entire Bohai Sea showed a significant decreasing trend (−0.013 mg/m3/year), while the Zsd exhibited a significant increasing trend (0.0065 m/year), and both had regional-seasonal variations. In addition, the ensemble empirical mode decomposition (EEMD) results reveal highly nonlinear trends of Chl-a and Zsd. The linear and nonlinear trends of Chl-a and Zsd suggest the deterioration of water quality in the Bohai Sea was not continued over the past two decades. This study presents the first simultaneous investigation of Chl-a and Zsd using the 23 years of cloud-free reconstructions in the Bohai Sea. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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23 pages, 8689 KiB  
Article
Prediction of Changeable Eddy Structures around Luzon Strait Using an Artificial Neural Network Model
by Yuan Kong, Lu Zhang, Yanhua Sun, Ze Liu, Yunxia Guo and Yong Fang
Remote Sens. 2022, 14(2), 281; https://doi.org/10.3390/rs14020281 - 08 Jan 2022
Viewed by 1587
Abstract
Mesoscale eddies occur frequently in the Luzon Strait and its adjacent area, and accurate prediction of eddy structure changes is of great significance. In recent years, artificial neural network (ANN) has been widely applied in the study of physical oceanography with the continuous [...] Read more.
Mesoscale eddies occur frequently in the Luzon Strait and its adjacent area, and accurate prediction of eddy structure changes is of great significance. In recent years, artificial neural network (ANN) has been widely applied in the study of physical oceanography with the continuous accumulation of satellite remote sensing data. This study adopted an ANN approach to predict the evolution of eddies around the Luzon Strait, based on 25 years of sea level anomaly (SLA) data, 85% of which are used for training and the remaining 15% are reserved for testing. The original SLA data were firstly decomposed into spatial modes (EOFs) and time-dependent principal components (PCs) by the empirical orthogonal function (EOF) analysis. In order to calculate faster and save costs, only the first 35 PCs were selected as predictors, whereas their variance contribution rate reached 96%. The results of predicted reconstruction indicated that the neural network-based model can reliably predict eddy structure evaluations for about 15 days. Importantly, the position and variation of four typical eddy events were reconstructed, and included a cyclone eddy event, an eddy shedding event, an anticyclone eddy event, and an abnormal anticyclone eddy event. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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17 pages, 3927 KiB  
Article
Evolutions of 30-Year Spatio-Temporal Distribution and Influencing Factors of Suaeda salsa in Bohai Bay, China
by Hongyan Yin, Yuanman Hu, Miao Liu, Chunlin Li and Yu Chang
Remote Sens. 2022, 14(1), 138; https://doi.org/10.3390/rs14010138 - 29 Dec 2021
Cited by 14 | Viewed by 2164
Abstract
Suaeda salsa (L.) Pall. (S. salsa) acts as a pioneer species in coastal wetlands due to its high salt tolerance. It has significant biodiversity maintenance, socioeconomic values (e.g., tourism) due to its vibrant color, and carbon sequestration (blue carbon). Bohai Bay region, the [...] Read more.
Suaeda salsa (L.) Pall. (S. salsa) acts as a pioneer species in coastal wetlands due to its high salt tolerance. It has significant biodiversity maintenance, socioeconomic values (e.g., tourism) due to its vibrant color, and carbon sequestration (blue carbon). Bohai Bay region, the mainly distributed area of S. salsa, is an economic intensive region with the largest economic aggregate and population in northern China. The coastal wetland is one of the most vulnerable ecosystems with the urbanization and economic developments. S. salsa in Bohai Bay has been changed significantly due to several threats to its habitat in past decades. In this paper, we analyzed all available archived Landsat TM/ETM+/OLI images of the Bohai Bay region by using a decision tree algorithm method based on the Google Earth Engine (GEE) platform to generate annual maps of S. salsa from 1990 to 2020 at a 30-m spatial resolution. The temporal-spatial dynamic changes in S. salsa were studied by landscape metric analysis. The influencing factors of S. salsa changes were analyzed based on principal component analysis (PCA) and a logistic regression model (LRM). The results showed that S. salsa was mainly distributed in three regions: the Liao River Delta (Liaoning Province), Yellow River Delta (Shandong Province), and Hai River Estuary (Hebei Province, Tianjin). During the past 31 years, the total area of S. salsa has dramatically decreased from 692.93 km2 to 51.04 km2, which means that 92.63% of the area of S. salsa in the Bohai Bay region was lost. In the 641.89 km2 area of S. salsa that was lost, 348.80 km2 of this area was converted to other anthropic land use categories, while 293.09 km2 was degraded to bare land. The landscape fragmentation of S. salsa has gradually intensified since 1990. National Nature Reserves have played an important role in the restoration of suitable S. salsa habitats. The analysis results for the natural influencing factors indicated that precipitation, temperature, elevation, and distance to the coastline were considered to be the major influencing factors for S. salsa changes. The results are valuable for monitoring the dynamic changes of S. salsa and can be used as effective factors for the restoration of S. salsa in coastal wetlands. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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19 pages, 42687 KiB  
Article
Internal Tides and Their Intraseasonal Variability on the Continental Slope Northeast of Taiwan Island Derived from Mooring Observations and Satellite Data
by Yuqi Yin, Ze Liu, Yuanzhi Zhang, Qinqin Chu, Xihui Liu, Yijun Hou and Xinhua Zhao
Remote Sens. 2022, 14(1), 59; https://doi.org/10.3390/rs14010059 - 23 Dec 2021
Cited by 1 | Viewed by 2284
Abstract
In this study, strong internal tides were observed on the continental slope northeast of Taiwan Island. Owing to the lack of long-term observations, these tides’ intraseasonal variability and the impact of the Kuroshio Current remain unclear. This study aimed to fill in the [...] Read more.
In this study, strong internal tides were observed on the continental slope northeast of Taiwan Island. Owing to the lack of long-term observations, these tides’ intraseasonal variability and the impact of the Kuroshio Current remain unclear. This study aimed to fill in the gaps using one-year continuous mooring observations, satellite data and analysis data. The horizontal kinetic energy (HKE) of semidiurnal internal tides showed that there was conspicuous energy from 100 days to 200 days, which was mainly attributed to the cross-term of HKE. The impact of the Kuroshio Current and mesoscale eddies on the HKEs were assessed: Cyclonic (anticyclonic) mesoscale eddies propagated from the open ocean, weakened (strengthened) the Kuroshio and shifted the Kuroshio onshore (offshore) northeast of Taiwan Island. The weakened (strengthened) Kuroshio increased (decreased) the shoreward velocity at the mooring site, and the onshore (offshore) Kuroshio migration increased (decreased) the northeastward velocity and enhanced (weakened) the HKEs of internal tides by modulating the tidal energy horizontal propagation. The weakened (strengthened) Kuroshio also resulted in gentler (steeper) isopycnals across the slope and enhanced (weakened) the HKEs of internal tides by influencing the interaction between ocean stratification and bottom topography. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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20 pages, 6433 KiB  
Article
Influence of Storm Tidal Current Field and Sea Bottom Slope on Coastal Ocean Waves during Typhoon Malakas
by Meng Sun, Yongzeng Yang, Yutao Chi, Tianqi Sun, Yongfang Shi and Zengrui Rong
Remote Sens. 2021, 13(22), 4722; https://doi.org/10.3390/rs13224722 - 22 Nov 2021
Viewed by 2771
Abstract
Wave–current interaction in coastal regions is significant and complicated. Most wave models consider the influence of ocean current and water depth on waves, while the influence of the gradient of the sea bottom slope is not taken into account in most research. This [...] Read more.
Wave–current interaction in coastal regions is significant and complicated. Most wave models consider the influence of ocean current and water depth on waves, while the influence of the gradient of the sea bottom slope is not taken into account in most research. This study aimed to analyze and quantify the contribution of storm tidal currents to coastal ocean waves in a case where sea bottom slope was not ignored. Fourier analysis was applied to solve the governing equation and boundary conditions, and an analytic model for the calculation of the variation of amplitude of wave orbital motion was proposed. Ocean currents affect ocean waves through resonance. In this paper, an implemented instance of this analytic model was given, using the Shengsi area during Typhoon Malakas as an example. The results suggest that vertical variation in the amplitude of wave orbital motion is remarkable. The impact of wave–current interaction is noticeable where the gradient of the sea bottom slope is relatively large. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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17 pages, 10404 KiB  
Article
Statistical Characteristics of the Response of Sea Surface Temperatures to Westward Typhoons in the South China Sea
by Zhaoyue Ma, Yuanzhi Zhang, Renhao Wu and Rong Na
Remote Sens. 2021, 13(5), 916; https://doi.org/10.3390/rs13050916 - 01 Mar 2021
Cited by 7 | Viewed by 2188
Abstract
The strong interaction between a typhoon and ocean air is one of the most important forms of typhoon and sea air interaction. In this paper, the daily mean sea surface temperature (SST) data of Advanced Microwave Scanning Radiometer for Earth Observation System (EOS) [...] Read more.
The strong interaction between a typhoon and ocean air is one of the most important forms of typhoon and sea air interaction. In this paper, the daily mean sea surface temperature (SST) data of Advanced Microwave Scanning Radiometer for Earth Observation System (EOS) (AMSR-E) are used to analyze the reduction in SST caused by 30 westward typhoons from 1998 to 2018. The findings reveal that 20 typhoons exerted obvious SST cooling areas. Moreover, 97.5% of the cooling locations appeared near and on the right side of the path, while only one appeared on the left side of the path. The decrease in SST generally lasted 6–7 days. Over time, the cooling center continued to diffuse, and the SST gradually rose. The slope of the recovery curve was concentrated between 0.1 and 0.5. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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19 pages, 5608 KiB  
Article
Turbidity Estimation from GOCI Satellite Data in the Turbid Estuaries of China’s Coast
by Jiangang Feng, Huangrong Chen, Hailong Zhang, Zhaoxin Li, Yang Yu, Yuanzhi Zhang, Muhammad Bilal and Zhongfeng Qiu
Remote Sens. 2020, 12(22), 3770; https://doi.org/10.3390/rs12223770 - 17 Nov 2020
Cited by 16 | Viewed by 4329
Abstract
Knowledge of the distribution and variation of water turbidity directly represent important information related to the marine ecology and multiple biogeochemical processes, including sediment transport and resuspension and heat transfer in the upper water layer. In this study, a neural network (NN) approach [...] Read more.
Knowledge of the distribution and variation of water turbidity directly represent important information related to the marine ecology and multiple biogeochemical processes, including sediment transport and resuspension and heat transfer in the upper water layer. In this study, a neural network (NN) approach was applied to derive the water turbidity using the geostationary ocean color imager (GOCI) data in turbid estuaries of the Yellow River and the Yangtze River. The results showed a good agreement between the GOCI-derived turbidity and in situ measured data with a determination coefficient (R2) of 0.84, root mean squared error (RMSE) of 58.8 nephelometric turbidity unit (NTU), mean absolute error of 25.1 NTU, and mean relative error of 34.4%, showing a better performance than existing empirical algorithms. The hourly spatial distributions of water turbidity in April 2018 suggested that high turbidity regions were distributed in the Yellow River estuary, Yangtze River estuary, Hangzhou Bay, and coastal waters of Zhejiang Province. Furthermore, the relationship between water turbidity and tide were estimated. A defined turbid zone was defined to evaluate the diurnal variations of turbidity, which has subtle changes at different times. Our results showed an inverse relationship between turbidity and tide over six selected stations, i.e., when the value of turbidity is high, then the corresponding tidal height is usually low, and vice versa. The combined effects of tidal height and tidal currents could explain the phenomena, and other factors such as winds also contribute to the turbidity distributions. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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18 pages, 3523 KiB  
Article
Storm Surge Hazard Assessment of the Levee of a Rapidly Developing City-Based on LiDAR and Numerical Models
by Qingrong Liu, Chengqing Ruan, Jingtian Guo, Jian Li, Xihu Lian, Zhonghui Yin, Di Fu and Shan Zhong
Remote Sens. 2020, 12(22), 3723; https://doi.org/10.3390/rs12223723 - 12 Nov 2020
Cited by 7 | Viewed by 2092
Abstract
Rapidly developing cities could require an urgent hazard assessment to ensure the protection of their economy and population against natural disasters. However, these cities that have rapidly developed should have historical records of observations that are too short to provide sufficient data information [...] Read more.
Rapidly developing cities could require an urgent hazard assessment to ensure the protection of their economy and population against natural disasters. However, these cities that have rapidly developed should have historical records of observations that are too short to provide sufficient data information for such an assessment. This study used ocean numerical models (i.e., Finite-Volume Community Ocean Model (FVCOM) and Parabolic Mild-Slope Wave Module (MIKE 21 PMS) to reconstruct data for a storm surge hazard assessment of the levee at Weifang (China). LiDAR (Light Detection and Ranging) data were also used to obtain 3D point cloud data and the structure of the levee. The designed levee height was calculated based on the simulations and 3D point cloud data, and the results were compared with measured heights to evaluate whether the levee is sufficiently high to satisfy the safety requirement. The findings of this work will enhance the marine disaster prevention capacity of the region and could help reduce economic losses associated with marine-related disasters. The results could also provide support for future work on disaster prevention in the field of coastal marine engineering. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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28 pages, 5823 KiB  
Article
Impact of Enhanced Wave-Induced Mixing on the Ocean Upper Mixed Layer during Typhoon Nepartak in a Regional Model of the Northwest Pacific Ocean
by Chengcheng Yu, Yongzeng Yang, Xunqiang Yin, Meng Sun and Yongfang Shi
Remote Sens. 2020, 12(17), 2808; https://doi.org/10.3390/rs12172808 - 30 Aug 2020
Cited by 6 | Viewed by 3906
Abstract
To investigate the effect of wave-induced mixing on the upper ocean structure, especially under typhoon conditions, an ocean-wave coupled model is used in this study. Two physical processes, wave-induced turbulence mixing and wave transport flux residue, are introduced. We select tropical cyclone (TC) [...] Read more.
To investigate the effect of wave-induced mixing on the upper ocean structure, especially under typhoon conditions, an ocean-wave coupled model is used in this study. Two physical processes, wave-induced turbulence mixing and wave transport flux residue, are introduced. We select tropical cyclone (TC) Nepartak in the Northwest Pacific ocean as a TC example. The results show that during the TC period, the wave-induced turbulence mixing effectively increases the cooling area and cooling amplitude of the sea surface temperature (SST). The wave transport flux residue plays a positive role in reproducing the distribution of the SST cooling area. From the intercomparisons among experiments, it is also found that the wave-induced turbulence mixing has an important effect on the formation of mixed layer depth (MLD). The simulated maximum MLD is increased to 54 m and is only 1 m less than the observed value. The wave transport flux residue shows a dominant role in the mixed layer temperature (MLT) changing. The mean error of the MLT is reduced by 0.19 °C compared with the control experiment without wave mixing effects. The study shows that the effect of wave mixing should be included in the upper ocean structure modeling. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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19 pages, 6915 KiB  
Article
Monitoring Suaeda salsa Spectral Response to Salt Conditions in Coastal Wetlands: A Case Study in Dafeng Elk National Nature Reserve, China
by Xia Lu, Sen Zhang, Yanqin Tian, Yurong Li, Rui Wen, JinYau Tsou and Yuanzhi Zhang
Remote Sens. 2020, 12(17), 2700; https://doi.org/10.3390/rs12172700 - 20 Aug 2020
Cited by 12 | Viewed by 3231
Abstract
This paper reports on monitored Suaeda salsa spectral response to salt conditions in coastal wetlands, using spectral measurements and remotely sensed algorithms. Suaeda salsa seedlings were collected from the Dafeng Elk National Nature Reserve (DENNR) in Jiangsu Province, China. We treated 21 Suaeda [...] Read more.
This paper reports on monitored Suaeda salsa spectral response to salt conditions in coastal wetlands, using spectral measurements and remotely sensed algorithms. Suaeda salsa seedlings were collected from the Dafeng Elk National Nature Reserve (DENNR) in Jiangsu Province, China. We treated 21 Suaeda salsa seedlings planted in pots with 7 different salt concentrations (n = 3 for each concentration) to assess their response to varying salt conditions. Various plant growth indicators, including chlorophyll content, fresh weight, dry weight, and canopy hyperspectral reflectance, were measured. One-way analysis of variance (ANOVA) and post hoc multiple comparisons of least-significant difference (LSD) were used to explore the physiological indicators of sensitivity to salt treatment. Red edge parameters and spectral reflectance indices were used to analyze spectral response to salt conditions and to investigate the potential for remotely sensing physiological parameters which are sensitive to salt conditions. The results indicated that among these physiological indicators, the total chlorophyll content differed significantly with salt conditions, being highest at 50 mmol/L, whereas the differences observed for the morphological parameters were highest at 200 mmol/L. In addition, new vegetation indices were significantly more responsive to salt concentrations than were traditional red edge parameters. The two vegetation indices, D854/D792 and (D792 − D854)/(D792 + D854), were the most sensitive to the total chlorophyll content, and these also strongly correlated with salt concentrations. An analysis of the responses of plant growth indicators to salt treatment showed that soil having a salt concentration of 50~200 mmol/L is most suitable for the growth of Suaeda salsa. These results suggest the potential for using remote sensing to effectively interpret the causes of salt-induced spectral changes in Suaeda salsa. This methodology also provides a new reference for the inversion model of estimating the total chlorophyll content of Suaeda salsa under different salt concentrations in similar coastal wetlands, whether in China or elsewhere. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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23 pages, 6450 KiB  
Article
Coastline Fractal Dimension of Mainland, Island, and Estuaries Using Multi-temporal Landsat Remote Sensing Data from 1978 to 2018: A Case Study of the Pearl River Estuary Area
by Xinyi Hu and Yunpeng Wang
Remote Sens. 2020, 12(15), 2482; https://doi.org/10.3390/rs12152482 - 03 Aug 2020
Cited by 8 | Viewed by 3777
Abstract
The Pearl River Estuary Area was selected for this study. For the past 40 years, it has been one of the most complex coasts in China, yet few studies have analyzed the complexity and variations of the area’s different coastlines. In this investigation, [...] Read more.
The Pearl River Estuary Area was selected for this study. For the past 40 years, it has been one of the most complex coasts in China, yet few studies have analyzed the complexity and variations of the area’s different coastlines. In this investigation, the coastlines of the Pearl River Estuary Area were extracted from multi-temporal Landsat remote sensing data from 1978, 1988, 1997, 2008, and 2018. The coastline of this area was classified into mainland, island, and estuarine. To obtain more detailed results of the mainland and island, we regarded this area as the main body, rezoned into different parts. The box-counting dimension was applied to compute the bidimensional (2D) fractal dimension. Coastline length and the fractal dimension of different types of coastline and different parts of the main body were calculated and compared. The fractal dimension of the Pearl River Estuary Area was found to have increased significantly, from 1.228 to 1.263, and coastline length also increased during the study period. The island and mainland showed the most complex coastlines, while estuaries showed the least complexity during the past forty years. A positive correlation was found between length and 2D-fractal dimension in some parts of the study area. Land reclamation had the strongest influence on fractal dimension variations. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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12 pages, 2684 KiB  
Article
Increasing Historical Tropical Cyclone-Induced Extreme Wave Heights in the Northern East China Sea during 1979 to 2018
by Shuiqing Li, Haoyu Jiang, Yijun Hou, Ning Wang and Jiuyou Lu
Remote Sens. 2020, 12(15), 2464; https://doi.org/10.3390/rs12152464 - 31 Jul 2020
Cited by 7 | Viewed by 2350
Abstract
Tropical cyclone (TC)-induced wind waves are a major concern in coastal safety, therefore quantifying the long-term change in extreme TC waves is critical for the design of coastal infrastructures and for understanding variations in coastal morphology. In this study, a trend analysis is [...] Read more.
Tropical cyclone (TC)-induced wind waves are a major concern in coastal safety, therefore quantifying the long-term change in extreme TC waves is critical for the design of coastal infrastructures and for understanding variations in coastal morphology. In this study, a trend analysis is performed on the TC-induced extreme wave heights in the northern East China Sea using numerically simulated wave height data during the period of 1979 to 2018. The simulation was forced with historical TC winds constructed using a parametric TC wind model with satellite-observed TC best-track data as the input. The results show consistently increasing extreme wave heights throughout the study region, which are induced predominantly by the increasing TC intensity. The increase rates (0.01–0.08 m yr−1) are relatively large (small) in offshore (nearshore) waters and at relatively high (low) latitudes. The spatial variability of the wave height trend is highly sensitive to the type of TC track. An analytical model of extreme wave height trend is developed that can efficiently estimate the rate of change in the extreme wave heights using extreme wind speed information. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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20 pages, 6060 KiB  
Article
Analyzing the Effects of Sea Surface Temperature (SST) on Soil Moisture (SM) in Coastal Areas of Eastern China
by Yingying Liu, Yuanzhi Zhang, Jingze Cai and Jin Yeu Tsou
Remote Sens. 2020, 12(14), 2216; https://doi.org/10.3390/rs12142216 - 10 Jul 2020
Cited by 3 | Viewed by 2066
Abstract
In this paper, we applied the re-analysis data cobe-SST (cobe-sea surface temperature) and Global Land Data Assimilation System (GLDAS) surface soil moisture (SM) data from 1961 to 2011 by using regional correlation analysis and time series causality analysis to trace annual variations in [...] Read more.
In this paper, we applied the re-analysis data cobe-SST (cobe-sea surface temperature) and Global Land Data Assimilation System (GLDAS) surface soil moisture (SM) data from 1961 to 2011 by using regional correlation analysis and time series causality analysis to trace annual variations in and identify the abnormal relationship of sea surface temperature (SST) in the eastern China Sea and SM in eastern China (EC). We also used satellite Moderate Resolution Imaging Spectroradiometer (MODIS) SST and AMSR-E SM data to examine the correlation of SST and SM in EC from 2004–2009. The results show that the SST in the eastern China Sea has experienced a warming trend since 1987, whereas the SM in EC has shown a drying trend since 1978. Before 1967 and after 1997, SST and SM changed during opposite phases, whereas from 1967 to 1997 they changed during the same phase. The differences between them may result from the abnormal summer precipitation causing abnormal SM. According to the regional correlation analysis, SST of the East China Sea is significantly related to SM in the southeast coastal area, and temporal sequence causality analysis shows that SST is correlated with and has higher influence on SM than vice versa. SM during spring and autumn shows a similar correlation with SST during the four seasons, so that SM in spring and autumn is positively correlated with SST in autumn and negatively correlated with SST in other seasons. SM in summer and winter correlated with SST in the four seasons, contradicting the foregoing conclusions. All these findings indicate that the thermodynamic state of the eastern China Sea has affected SM in EC. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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21 pages, 14190 KiB  
Article
A Cost-Effective Method to Reproduce the Morphology of the Nearshore and Intertidal Zone in Microtidal Environments
by Stefano Furlani, Valeria Vaccher, Vanja Macovaz and Stefano Devoto
Remote Sens. 2020, 12(11), 1880; https://doi.org/10.3390/rs12111880 - 10 Jun 2020
Cited by 3 | Viewed by 3635
Abstract
The photogrammetric method is widely used in coastal areas and in submerged environments. Time-lapse images collected with unmanned aerial vehicles are used to reproduce the emerged areas, while images taken by divers are used to reproduce submerged ones. Conversely, 3D models of natural [...] Read more.
The photogrammetric method is widely used in coastal areas and in submerged environments. Time-lapse images collected with unmanned aerial vehicles are used to reproduce the emerged areas, while images taken by divers are used to reproduce submerged ones. Conversely, 3D models of natural or human-made objects lying at the water level are severely affected by the difference in refractive index between air and seawater. For this reason, the matching of 3D models of emergent and submerged coasts has been very rarely tested and never used in Earth Sciences. The availability of a large number of time-lapse images, collected at the intertidal zone during previous snorkel surveys, encouraged us to test the merging of 3D models of emerged and submerged environments. Considering the rapid and effective nature of the aforementioned program of swim surveys, photogrammetric targets were not used during image acquisition. This forced us to test the matching of the independent models by recognizing prominent landforms along the waterline. Here we present the approach used to test the method, the instrumentation used for the field tests, and the setting of cameras fixed to a specially built aluminum support console and discuss both its advantages and its limits compared to UAVs. 3D models of sea cliffs were generated by applying structure-from-motion (SfM) photogrammetry. Horizontal time-lapse images, collected with action cameras while swimming parallel to the coastline at nearly constant velocity, were used for the tests. Subsequently, prominent coastal landforms were used to couple the independent models obtained from the emergent and submerged cliffs. The method was pilot tested in two coastal sites in the north-eastern Adriatic (part of the Mediterranean basin). The first site was a 25 m sea wall of sandstone set within a small harbor, while the second site was a 150 m route below plunging limestone cliffs. The data show that inexpensive action cameras provide a sufficient resolution to support and integrate geomorphological field surveys along rocky coastlines. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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21 pages, 7706 KiB  
Article
Effects of Typhoon Paths on Storm Surge and Coastal Inundation in the Pearl River Estuary, China
by Mei Du, Yijun Hou, Po Hu and Kai Wang
Remote Sens. 2020, 12(11), 1851; https://doi.org/10.3390/rs12111851 - 08 Jun 2020
Cited by 12 | Viewed by 3096
Abstract
A coastal inundation simulation system was developed for the coast of the Pearl River estuary (PRE), which consists of an assimilation typhoon model and the coupled ADCIRC (Advanced Circulation) + SWAN (Simulating Waves Nearshore) model. The assimilation typhoon model consists of the Holland [...] Read more.
A coastal inundation simulation system was developed for the coast of the Pearl River estuary (PRE), which consists of an assimilation typhoon model and the coupled ADCIRC (Advanced Circulation) + SWAN (Simulating Waves Nearshore) model. The assimilation typhoon model consists of the Holland model and the analysis products of satellite images. This is the first time an assimilation typhoon model has been implemented and tested for coastal inundation via case studies. The simulation results of the system agree well with the real measurements. Three observed typhoon paths (Hope, Nida, and Hato) were chosen to be the studied paths based on their positions relative to the PRE, China. By comparing the results of experiments with different forcing fields, we determined that the storm surge and the coastal inundation were mainly induced by wind forcing. By simulating coastal inundation for different typhoon center speeds, the Hato3 path most easily causes coastal inundation in the PRE. Moreover, the moving speed of the typhoon’s center significantly affects the coastal inundation in the PRE. The inundation becomes very serious as the movement of the typhoon center was slow down. This study provides a new reference for future predictions of coastal inundations. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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21 pages, 7873 KiB  
Article
Risk Prediction of Coastal Hazards Induced by Typhoon: A Case Study in the Coastal Region of Shenzhen, China
by Yunxia Guo, Yijun Hou, Ze Liu and Mei Du
Remote Sens. 2020, 12(11), 1731; https://doi.org/10.3390/rs12111731 - 28 May 2020
Cited by 11 | Viewed by 3723
Abstract
This study presents a risk prediction of coastal hazards induced by typhoons, which are a severe natural hazard that often occur in coastal regions. Taking the coastal hazards happened in Shenzhen as a case study, where is a southeast coastal city of China, [...] Read more.
This study presents a risk prediction of coastal hazards induced by typhoons, which are a severe natural hazard that often occur in coastal regions. Taking the coastal hazards happened in Shenzhen as a case study, where is a southeast coastal city of China, we described a methodology to predict the typhoon wind-surge-wave hazard. A typhoon empirical tracking model was adopted to construct full-track typhoon events for 1000 years, based on the statistical characteristics of observed typhoons from satellite imageries. For each individual typhoon, a wind-field model is applied to compute the wind speeds, while the Simulating Waves Nearshore and Advanced Circulation (SWAN+ADCIRC) coupled model is applied to simulate the significant wave heights (SWHs) and storm surge heights. By frequency distribution histogram, it is noted that there exhibits a heavy tail in the probability distribution of maximum surge heights and a thin tail of the peak wind speeds and SWHs in the coastal area of Shenzhen, China. Using the Generalized Pareto Distribution (GPD) model, the extreme values of typhoon wind-surge-wave associated with various return periods can be predicted. Taking account into the combined effects of the wind, surge and wave, the joint hazard maps of typhoon wind-surge-wave can be produced for the study area. The methodology of this case study can provide a new reference for risk prediction of coastal hazards induced by typhoon in similar coastal regions like Shenzhen, China. Full article
(This article belongs to the Special Issue Coastal Environments and Coastal Hazards)
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