Chinese Coastal Regions Research Articles

Evaluations of storm tide hazard along the coast of China using synthetic dynamic tropical cyclone events

Concurring with high astronomical tides, storm surges have caused devastating damage in low-lying areas along the Chinese coastal regions. However, accurately calculating tropical cyclone (TC) storm tide hazards, especially those with long return periods, has proven challenging due to limited temporal and spatial information on TCs. In this study, we adopt the Synthetic Dynamic TC Method (SDTM), which enables a more robust estimation of storm tide hazards by generating a large number of synthetic TCs based on historical best track data and ocean-atmosphere environmental data. Within the SDTM framework, synthetic TCs corresponding to 10,000 years are validated using several statistical metrics, and the associated storm tides are simulated. For comparison, we employ the Historical Storm Method (HSM) to simulate storm tides for historical TCs from 1950 to 2019. Storm tide hazard curves are calculated and compared using these two methods. Our results demonstrate that the SDTM can robustly estimate storm tide hazards for both short and long return periods, whereas the HSM performs well for short return periods but struggles to reliably assess storm tide hazards for long return periods. Notably, within the SDTM, storm tide height exhibits nonlinear growth with increasing return periods in the Gumbel plot, a phenomenon not observed in the HSM due to the limited time span of TC records. With sufficient TC data, the spatial storm tide hazard maps obtained from the SDTM can serve as a robust foundation for developing disaster prevention and mitigation policies.

Multi-class multi-label classification of social media texts for typhoon damage assessment: a two-stage model fully integrating the outputs of the hidden layers of BERT

ABSTRACT With the development of social media, it has become increasingly important to quickly and accurately identify social media texts related to disasters (e.g. typhoon) to aid in rescue and recovery efforts. Currently, multi-class classification and pre-trained language model Bidirectional Encoder Representations from Transformers (BERT) are widely used for text classification. However, most studies on typhoon damage classification are multi-class single-label, which contradicts to the reality that a social media text may correspond to multiple types of damage. Moreover, the outputs of the hidden layers of BERT are not fully utilized. This paper proposes a two-stage multi-class multi-label classification method for typhoon damage assessment by fully integrating the outputs of the hidden layers of BERT. In the first stage, sentence vectors are adopted to identify typhoon damage-related texts. In the second stage, word matrices are applied for multi-class multi-label classification to further classify the texts into five damage categories (i.e. transportation, public, electricity, forestry, and waterlogging). The two stages are trained end-to-end to identify typhoon damage from social media texts. Experiments on SinaWeibo texts during typhoon landfall in Chinese coastal regions demonstrate that the proposed method can effectively improve the accuracy of text classification and comprehensively assess typhoon damage.

Identification and Verification of the Blue Pigment in the Edible Jellyfish (Rhopilema esculentum)

Rhopilema esculentum is widely cultured in Chinese coastal regions and has thousand years of consumption history in China. Despite R. esculentum owns multiple colors (mainly ochre and blue) in aquaculture ponds, little is known about the pigments and color formation. This study identified and verified the blue pigment of R. esculentum. Results showed that the blue pigment of R. esculentum has 262 amino acids with 54.96% identity to the blue pigment protein precursor of Rhizostoma pulmo. The blue pigment of R. esculentum has Kringle and Frizzled domains, which is in accordance with rhizostomins characteristics. Compared to ochre R. esculentum, the expression level of blue pigment increased 3.49-fold in blue R. esculentum. In addition, overexpression of the blue pigment in Rhodosporidium toruloides made transformant cells blue under blue light excitation. Our findings provide knowledge for the blue color formation of R. esculentum and will benefit the color selection of R. esculentum with excellent traits.

Regimes of Bondage: The Encounter between Early Modern European and Asian Slaveries

AbstractThis special issue focuses on the broader context and interconnectedness of different slave regimes in early modern Asia. Various transnational commercial and imperial projects influenced the waxing and waning of individual slave regimes, while internal and interpersonal conditions within polities also played important roles. The well-known European seaborne empires of Spain, Portugal, the Netherlands, and England were major drivers of this early modern slavery, but they coexisted and competed with other groups of trader-raiders. These included merchants from the Islamicate world and Chinese coastal regions, which connected Southeast Asia, Japan, Korea, and other regions. These extensive markets linked different regions together, such as the Malabar Coast with East Africa, the Arabian Peninsula, and the Red Sea. While the focus is on the Iberian expansion and its impact on the slave trade, this special issue acknowledges that slavery in Asia should be understood as a result of multiple overlapping and interacting regimes. Each article examines a particular regime while emphasizing its interactions with neighboring regions during the early modern period. The main focus is on the encounters between different slave regimes facilitated by early modern commercial networks. The history of slavery in early modern Asia involved clashes and cross-pollination between disparate slave systems. A further contribution relates to the terminology used to define and understand slavery in non-European contexts, which is still a subject of debate. The concept of “regimes of bondage” is adopted as an umbrella term to encompass the various forms of coerced, subaltern, and dependent labor in Asia during this period. Finally, by using local categories and sources, including European and non-European language materials, the special issue aims to recover marginalized perspectives and highlight the complexity and challenges of studying slavery in Asia.

Understanding the efficiency of “political attention and governance action” on marine waste discharge in the coastal provinces in China

This study examines the “black box” of the policy process by evaluating the efficiency of “political attention and governance action” as a two-stage continuum and investigating the influencing factors in marine waste discharge governance. The results of empirical analysis in the 11 Chinese coastal provincial regions suggest that the overall efficiency fluctuated from 1999 to 2016 with a minor reduction. The developed provinces such as Jiangsu, Zhejiang, Shanghai and Guangdong have low efficiency in overall evaluation. In the first stage, the transferring efficiency from political attention to actions does not change considerably despite fluctuations in 2012–2016. The second-stage efficiency, or the efficiency of the governance actions, has been declining since 2008 except for a brief spike in 2014. There exists a feedback impact between the two stages. Economic competition, as measured by the average GDP of neighbouring provinces, has more negative impacts on the first-stage efficiency.

Microsatellite markers reveal genetic diversity and population structure of Portunus trituberculatus in the Bohai Sea, China

The swimming crab, Portunus trituberculatus, is one of the main aquaculture species in Chinese coastal regions due to its palatability and high economic value. To obtain a better understanding of the genetic diversity of P. trituberculatus in the Bohai Sea, the present study used 40 SSR loci to investigate the genetic diversity and population structure of 420 P. trituberculatus individuals collected from seven populations in the Bohai Sea. Genetic parameters revealed a low level of genetic diversity in the cultured population (SI = 1.374, He = 0.687, and PIC = 0.643) in comparison with wild populations (SI ≥ 1.399, He ≥ 0.692, and PIC ≥ 0.651). The genetic differentiation index (Fst) and gene flow (Nm) ranged from 0.001 to 0.060 (mean: 0.022) and 3.917 to 249.750 (mean: 31.289) respectively, showing a low differentiation among the seven populations of P. trituberculatus. Population structure analysis, phylogenetic tree, and principal component analysis (PCA) demonstrated that the seven groups of P. trituberculatus were divided into four subpopulations (K = 4), but the correlation between genetic structure and geographical distribution was not obvious. These results are expected to provide useful information for the fishery management of wild swimming crabs.

Can environmental regulation promote the green output bias in China's mariculture?

The green output bias of technological progress is the key factor driving the green transformation of mariculture. This study considers whether environmental regulation can promote the green output bias. Utilizing data envelopment analysis (DEA), we decomposed the green output biased technological progress index (OBTC) and constructed the index to measure the output bias between output value and pollutant emissions. The results show spatial and temporal differences in the green output bias, with different bias values for three major Chinese coastal regions during the study period. As the bias value mainly fluctuates around the zero value, the degree of green output bias must be enhanced. Considering the heterogeneity of environmental regulation, we empirically study the relation that exists between environmental regulation and green output bias. Our findings indicate a U-shaped relation between two categories of environmental regulation and the green output bias. Green technology partially intermediates the mechanisms by which these environmental regulations influence green output bias. Our results have implications for policymakers and other stakeholders for strengthening environmental regulation, promoting green technological innovation, and the scientific planning of the species and scale of mariculture to promote sustainable development.

Changes of Chinese Coastal Regions Induced by Land Reclamation as Revealed through TanDEM-X DEM and InSAR Analyses

Chinese coastal topography has changed significantly over the last two decades due to human actions such as the development of extensive land reclamation projects. Newly-reclaimed lands typically have low elevations (<10 m) and often experience severe ground subsidence. These conditions, combined with the more frequent occurrence of extreme sea-level events amplified by global climate change, lead to an increased risk of flooding of coastal regions. This work focuses on twelve Chinese coastal areas that underwent significant changes from 2000 to 2015 in their environments, correlated to relevant land reclamation projects. First, the ground changes between 2000 and 2015 were roughly computed by comparing the TanDEM-X and the Shuttle Radar Topography Mission (SRTM) digital elevation models of the investigated areas. These results indicate that six of the analyzed coastal zones have reclaimed more than 200 km2 of new lands from 2000 to 2015, with five of them in northern China. Second, we focused specifically on the city of Shanghai, and characterized the risk of flood in this area. To this purpose, two independent sets of synthetic aperture radar (SAR) data collected at the X- and C-band through the COSMO-SkyMed (CSK) and the European Copernicus Sentinel-1 (S-1) sensors were exploited. We assumed that the still extreme seawater depth is chi-square distributed, and estimated the probability of waves overtopping the coast. We also evaluated the impact on the territory of potential extreme flood events by counting the number of very-coherent objects (at most anthropic, such as buildings and public infrastructures) that could be seriously affected by a flood. To forecast possible inundation patterns, we used the LISFLOOD-FP hydrodynamic model. Assuming that an extreme event destroyed a given sector of the coastline, we finally computed the extent of the flooded areas and quantified its impact in terms of coherent structures potentially damaged by the inundation. Experimental results showed that two coastline segments located in the southern districts of Shanghai, where the seawalls height is lower, had the highest probability of wave overtopping and the most significant density of coherent objects potentially subjected to severe flood impacts.

Research on the biology and ecology of the harmful algal bloom species Phaeocystis globosa in China: Progresses in the last 20 years

Chinese researchers have made substantial progresses in research on the harmful algal bloom (HAB) species Phaeocystis globosa since the first P. globosa bloom outbreak in the Chinese coastal waters in 1997. However, as many results, especially the earlier ones, were published in non-English literature, much of the research on P. globosa biology, ecology, and biogeochemistry made by Chinese researchers have been unknown to colleagues from other countries. We review current knowledge on taxonomy, morphology, genetics, physiology, survival strategies and mitigation of P. globosa gained by Chinese researchers from the past two decades. P. globosa is the only Phaeocystis species that causes blooms in the Chinese waters, although other Phaeocystis species including P. jahnii and P. cordata have been detected in Chinese coastal regions. P. globosa has a complex life history with at least two morphotypes including a haploid flagellate and a diploid colonial cell. Colonial P. globosa blooms typically occur in winter after a diatom bloom in coastal waters of the South China Sea. P. globosa in Chinese coastal waters usually has extremely large colonial sizes, up to 3 cm in diameter, an order of magnitude greater than that observed in European coastal waters. The development of giant colonies is associated with enhanced sinking rate, limited nutrient diffusion, as well as decreased stability of colonies. The Chinese P. globosa strains also showed strong genetic diversity and physiological plasticity, being able to grow and develop into colonies at higher temperature and irradiance relative to that in European waters. High genetic diversity of P. globosa was revealed by developing high-resolution and high-specificity molecular markers including Phaeocystis globosa chloroplast 1 (pgcp1). Due to the severe impact of P. globosa on ecology and economy, much effort has been made to mitigate P. globosa blooms including the application of modified clays. Overall, P. globosa in the Chinese waters demonstrate unique genetic, phenotypical and physiological features that differ from P. globosa in other ocean regions. Further studies are needed to explore how environmental factors trigger the occurrence of P. globosa blooms and ascertain the impact of P. globosa blooms on the environment.

Port system evolution in Chinese coastal regions: A provincial perspective

Against the background of provincial port integration in China, provincial port groups have become critical market players in the port industry. It has become necessary to review the evolution of the port system in Chinese coastal regions from a provincial perspective. This paper investigates the evolution of the Chinese port system by treating eleven coastal provinces as the units of analysis. The port system is categorized into four segments according to cargo type, namely, containers, solid bulk cargo, general cargo and liquid bulk cargo. Multiple methods are applied to study the port system from the perspectives of market shares, cargo concentrations, the port hierarchy and port specialization. The findings suggest that no province holds a leading market position in all cargo sectors, and interprovincial port competition remains intense. The degree of specialization in the provincial port systems is generally moderate, though Hebei Province is an exception with a high level of port specialization due to its special geographical location. This paper also elaborates on several policy implications for provincial port groups.

Assessing and zoning of typhoon storm surge risk with a geographic information system (GIS) technique: a case study of the coastal area of Huizhou

Abstract. Storm surge is one of the most destructive marine disasters to life and property for Chinese coastal regions, especially for Guangdong Province. In Huizhou city, Guangdong Province, due to the high concentrations of chemical and petroleum industries and the high population density, the low-lying coastal area is susceptible to the storm surge. Therefore, a comprehensive risk assessment of storm surge over the coastal area of Huizhou can delimit zones that could be affected to reduce disaster losses. In this paper, typhoon intensity for the minimum central pressure of 880, 910, 920, 930, and 940 hPa (corresponding to a 1000-, 100-, 50-, 20-, and 10-year return period) scenarios was designed to cover possible situations. The Jelesnianski method and the Advanced Circulation (ADCIRC) model coupled with the Simulating Waves Nearshore (SWAN) model were utilized to simulate inundation extents and depths of storm surge over the computational domain under these representative scenarios. Subsequently, the output data from the coupled simulation model (ADCIRC–SWAN) were imported to the geographic information system (GIS) software to conduct the hazard assessment for each of the designed scenarios. Then, the vulnerability assessment was made based on the dataset of land cover types in the coastal region. Consequently, the potential storm surge risk maps for the designed scenarios were produced by combining hazard assessment and vulnerability assessment with the risk matrix approach. The risk maps indicate that due to the protection given by storm surge barriers, only a small proportion of the petrochemical industrial zone and the densely populated communities in the coastal areas were at risk of storm surge for the scenarios of 10- and 20-year return period typhoon intensity. Moreover, some parts of the exposed zone and densely populated communities were subject to high and very high risk when typhoon intensities were set to a 50- or a 100-year return period. Besides, the scenario with the most intense typhoon (1000-year return period) induced a very high risk to the coastal area of Huizhou. Accordingly, the risk maps can help decision-makers to develop risk response plans and evacuation strategies in coastal communities with a high population density to minimize civilian casualties. The risk analysis can also be utilized to identify the risk zones with the high concentration of chemical and petroleum industries to reduce economic losses and prevent environmental damage caused by the chemical pollutants and oil spills from petroleum facilities and infrastructures that could be affected by storm surge.

Offshore Wind Replaces Coal and Reduces Transmission, Enabling China to Meet the 1.5°C Climate Imperative

Author(s): Li, Bo; Ma, Ziming; He, Gang; Hidalgo-Gonzalez, Patricia; Fedorova, Natalie; Chen, Minyou; Kammen, Daniel M

Environmental response to growth in the marine economy and urbanization: A heterogeneity analysis of 11 Chinese coastal regions using a panel vector autoregressive model

The effect of urbanization on the environment in coastal regions has been extensively examined in previous studies, but neither the reverse effect nor the role of the marine economy has been investigated. To address this gap, this study uses a panel vector autoregressive model to further explore the interactions between marine economic growth, marine pollution, and urbanization in 11 Chinese coastal provinces/municipalities from 2000 to 2016. The per capita gross ocean product (GOP) and the per capita volume of industrial wastewater discharged directly into the sea decreased during the research period, whereas the urbanization rate increased. The spatial pattern of the main polluted areas showed a shift from north to south. Marine economic growth had a single-direction influence on marine pollution and urbanization in coastal regions, implying that urban expansion did not increase the ocean output. Consistent with previous findings, urban expansion aggravated environmental damage to the ocean. According to both impulse response analysis and variance decomposition, urbanization had a significant role in explaining variation in the three factors examined in this study. In addition, according to heterogeneity analysis, the three factors were most affected in the mid-income regions and southern coastal areas, while the areas with more developed marine services could better resist the negative effects of marine pollution and urban expansion. The policy implications of increasing the proportion of the marine economy and of controlling the acceleration of urbanization are explored.

An Expected Utility-Based Optimization of Slow Steaming in Sulphur Emission Control Areas by Applying Big Data Analytics

This paper analyses the operator's risk-based decision (RBD) company for slow steaming, and creates a sailing speed optimization model for slow steaming (SSOM-SS), aiming to balance the expected utility-based objectives (EUO) of fuel consumption, SOx emissions and delivery delay. Considering the limitations of existing theoretical fuel consumption functions under uncertainties in voyages, the authors applies big data analytics (BDA) techniques like data fusion and feature selection to provide the SSOM-SS with accurate and suitable data on fuel consumption. In addition, a solver is built based on the genetic algorithm (GA) to solve the SSOM-SS. The effectiveness of the SSOM-SS is verified through a case study on the RBD for slow steaming of an Orient Overseas Container Line (OOCL) containership sailing across the sulphur emission control areas (SECAs) in Chinese coastal regions. The results show that the SSOM-SS can facilitate the RBD for slow steaming, and provide a novel tool for sailing speed optimization.

Торговые взаимодействия регионов КНР с Россией: эффект границ

The paper analyzes the dynamics and structure of trade interaction between Chinese regions and Russia using official Chinese data and assesses the border effects for export and import flows. The analysis shows that Chinese imports from Russia exhibit a much more uneven distribution across Chinese regions than exports. The results of the gravity model estimation indicate that the size of the border effect for exports of Chinese regions to Russia was larger compared to trade barriers with other countries. At the same time, the hurdles impeding the access of Russian production to Chinese regional markets expressed in the ad-valorem tariff equivalent were higher than for other countries. The estimates reveal that Russian exports to Chinese regions have been experiencing higher barriers in recent years than Chinese regional exports to Russia. The findings suggest that leveling barriers would reinforce the access of Chinese coastal regions to the Russian market, making exports to Russia even less evenly distributed across Chinese regions. A substantial reduction of barriers is likely to increase Russian imports in China thanks to the growing flows of Russian goods to virtually all Chinese regions. Accordingly, Russian exporters need to diversify their supply across Chinese regions so as to bypass the middlemen and tap new regional markets in China

Bacterial Succession in Salt Marsh Soils Along a Short-term Invasion Chronosequence of Spartina alterniflora in the Yellow River Estuary, China.

As an exotic plant species, Spartina alterniflora seriously threatens native ecosystem function in Chinese coastal regions. Unveiling the dynamics of soil bacteria community during its invasion is essential for a better understanding of related biogeochemical processes, while the shift in soil bacterial community over invasive time remains unclear. A short-term chronosequence was identified to assess the impacts of Spartina alterniflora invasion on soil nutrients and bacterial community composition and structure (using 16S rRNA gene high-throughput sequencing) over the time of invasion (i.e., (1) at least 10 years, (2) nearly 5 years, (3) less than 2 years, and (4) in native salt marshes or 0 years) in the Yellow River Estuary. The results exhibited an orderly change in the soil physicochemical properties and bacterial community composition over the invasion time. Soil pH showed a significant decrease with the accumulation of soil organic matter (SOM), whereas soil nutrients such as soil dissolved organic carbon (DOC), total nitrogen (TN), nitrate (NO3-), ammonium (NH4+), K+, and Mg2+ were generally increased with the age of the invasion. The number of operational taxonomic units (OTUs, 97% similarity level) exhibited a decreasing trend, which suggested a decline in bacterial diversity with the invasion age. The dominant groups at the phylum level were Proteobacteria, Bacteroidetes, Chloroflexi, Acidobacteria, and Gemmatimonadetes (the sum of relative abundance was > 70% across all samples). The relative abundances of Chloroflexi and Gemmatimonadetes steadily decreased, while the abundance of Bacteroidetes significantly increased with the plant invasion. The distribution pattern of the soil bacteria was clearly separated according to the principal coordinate analysis (PCoA) and canonical correspondence analysis (CCA) in native and invaded salt marshes. The variation in the soil bacterial community was tightly associated with the soil physicochemical properties (Mantel test, P < 0.05). Variance partitioning analysis (VPA) showed that plant traits explained 4.95% of the bacterial community variation, and soil variables explained approximately 26.96% of the variation. Network analysis also revealed that plant invasion strengthens the interaction among soil bacterial communities. Overall, our findings highlight the bacterial community succession during the Spartina alterniflora invasion in coastal salt marsh soils, which can provide insight regarding the association between soil development and invasive plant.

Genetic and population analyses of Vibrio parahaemolyticus isolates from three major coastal regions in China.

Aim:This study aims to evaluate the genetic and population structure of Vibrio parahaemolyticus in the major coastal regions of China.Materials & methods:Multilocus sequence typing was performed.Results:Insertion of large sequence into recA happened in nearly 30 strains, which were untypeable by multilocus sequence typing. A collection of 307 V. parahaemolyticus isolates were typed into 160 sequence types, including 117 novel ones. eBURST analysis revealed five clonal complexes, 11 doublets, and 108 singletons. The 160 sequence types formed two main lineages in the phylogenetic analysis.Conclusion: V. parahaemolyticus along the Chinese coastal regions exhibits high levels of genetic diversity and has undergone significant purifying selection and frequent recombination. A deeper understanding of V. parahaemolyticus genetic diversity could be obtained at the level of genome sequences.

THE IDENTIFICATION OF LAND UTILIZATION IN COASTAL RECLAMATION AREAS IN TIANJIN USING HIGH RESOLUTION REMOTE SENSING IMAGES

Abstract. In recent decades, land reclamation activities have been developed rapidly in Chinese coastal regions, especially in Bohai Bay. The land reclamation areas can effectively alleviate the contradiction between land resources shortage and human needs, but some idle lands that left unused after the government making approval the usage of sea areas are also supposed to pay attention to. Due to the particular features of land coverage identification in large regions, traditional monitoring approaches are unable to perfectly meet the needs of effectively and quickly land use classification. In this paper, Gaofen-1 remotely sensed satellite imagery data together with sea area usage ownership data were used to identify the land use classifications and find out the idle land resources. It can be seen from the result that most of the land use types and idle land resources can be identified precisely.

Relationship between South China Sea summer monsoon onset and landfalling tropical cyclone frequency in China

Between 1979 and 2015, the anticorrelation between the frequency of landfalling tropical cyclones (LTCs) in mainland China from June to October and the South China Sea summer monsoon (SCSSM) onset date can be attributed to variations in the western North Pacific subtropical high (WNPSH) and monsoon trough (MT) that correspond to the SCSSM onset. When the SCSSM onset is early, the WNPSH shrinks northeastwards and the MT becomes increasingly strong and exhibits a northwards shift. These features lead to anomalous lower‐level cyclonic circulation around Luzon Island and a mid‐tropospheric easterly anomaly over the Chinese coastal regions, which favour the generation of TCs in the western part of the North Pacific that makes landfall on the southeastern coast of China. In contrast, the circulation anomaly prohibits landfalling TCs in mainland China when the SCSSM onset is delayed. The SCSSM onset has the potential to be an indicator of TC landfall frequency in mainland China.

Has China been exporting less particulate air pollution over the past decade?

AbstractParticulate matter (PM) pollution from China is transported eastward to Korea and Japan and has been suggested to influence surface air quality on the West Coast of the United States. However, remote sensing studies have been inconclusive as to recent trends in Chinese emissions and transport. We reconciled different passive remote sensing points of view and found that while aerosol optical thickness (AOT) as an indicator of particulate pollution has increased from the start of the observation period (2000) to 2006–2007 from the main Chinese coastal outflow regions, since then there has been a 10–20% decrease in AOT (with respect to 2007). Reductions were observed in spring, summer, and fall seasons. No improvement in exported PM pollution is found for the winter season.