Influence of Irregular Coastlines on a Tornadic Mesovortex in the Pearl River Delta during Monsoon Season.Part II:Numerical Experiments

As demonstrated in the first part of this study(Part I),wind-shift boundaries routinely form along the west coast of the Pearl River Delta due to the land-sea contrast of a“trumpet”shape coastline in the summer monsoon season.Through multiple numerical simulations,this article(Part II)aims to examine the roles of the trumpet-shaped coastline in the mesovortex genesis during the 1 June 2020 tornadic event.The modeling reproduced two mesovortices that are in close proximity in time and space to the realistic mesovortices.In addition to the modeled mesovortex over the triple point where strong ambient vertical vorticity was located,another mesovortex originated from an enhanced discrete vortex along an airmass boundary via shear instability.On the fine-scale storm morphology,finger-like echoes preceding hook echoes were also reproduced around the triple point.Results from sensitivity experiments suggest that the unique topography plays an essential role in modifying the vorticity budget during the mesovortex formation.While there is a high likelihood of an upcoming storm evolving into a rotating storm over the triple point,the simulation's accuracy is sensitive to the local environmental details and storm dynamics.The strengths of cold pool surges from upstream storms may influence the stretching of low-level vertically oriented vortex and thus the wrap-up of finger-like echoes.These findings suggest that the trumpet-shaped coastline is an important component of mesovortex production during the active monsoon season.It is hoped that this study will increase the situational awareness for forecasters regarding regional non-mesocyclone tornadic environments.

Computational Quantification of Map Projection Distortion by Fractal Dimension of Coastlines

Maps, essential tools for portraying the Earth’s surface, inherently introduce distortions to geographical features. While various quantification methods exist for assessing these distortions, they often fall short when evaluating actual geographic features. In our study, we took a novel approach by analyzing map projection distortion from a geometric perspective. We computed the fractal dimensions of different stretches of coastline before and after projection using the divide-and-conquer algorithm and image processing. Our findings revealed that map projections, even when preserving basic shapes, inevitably stretch and compress coastlines in diverse directions. This analysis method provides a more realistic and practical way to measure map-induced distortions, with significant implications for cartography, geographic information systems (GIS), and geomorphology. By bridging the gap between theoretical analysis and real-world features, this method greatly enhances accuracy and practicality when evaluating map projections.

Environmental Impacts of Solid Waste Landfills on Natural Ecosystems of Southern Caspian Sea Coastlines

The problem of solid waste landfills on Caspian Sea coastlines is one of the current concerns of the Iranian environmental authorities. Physical and environmental constraints as well as shortcomings in present municipal solid waste management are the main factors for environmental pollution and natural resources destruction in this geographical region. In order to reduce the above problems, this study has been carried out on the basis of a comparative assessment of the existing condition of landfill sites in natural ecosystems. In this study, 48 cities of the region have been investigated. All of them are located in Gilan and Mazandaran provinces. Total daily waste production in the study area is about 1209 tons that are dumped in open spaces and/or in aquatic and terrestrial ecosystems. Surveying of 53 physical, adaptability and constraint parameters as well as hygiene and environmental parameters in the landfills, based on “Monavari-94 Method” indicate that the main problem in all of them is a high groundwater table. In 42% of landfills, the groundwater level is between from 0.5 to 2 meters. This phenomenon may cause severe risks due to the infiltration of leachate into potable groundwater. Indeed, the results of the study show that 87.5% of the landfills are located in areas with unacceptable conditions. In spite of geographical and environmental problems and constraints and as a final alternative in this respect, the need for sanitary and technical solid waste management is the main need of the study areas.

Numerical simulations of rip currents off arc-shaped coastlines

The rip currents induced by waves off arc-shaped coastlines are seriously harmful to humans, but understanding of their characteristics is lacking. In this study, the FUNWAVE model was used to calculate the wave-induced currents in the Haller experiment and the ideal arc-shaped coast similar to Sanya Dadonghai, Hainan Province,China. The results showed that the FUNWAVE model has considerable ability to simulate the rip currents, and it was used to further simulate rip currents off arc-shaped coastlines to investigate their characteristics. The rip currents were found to be stronger as the curvature of arc-shaped coastline increased. Coastal beach slope exerts a significant influence on rip currents; in particular, an overly steep or overly mild slope is not conducive to creating rip currents. Furthermore, the rip currents were found to become weaker as the size of arc-shaped coast decreased. When the height and period of waves increase, the strength of rip currents also increases, and, in some cases, wave heights of 0.4 m may produce dangerous rip currents.

A Collaborative Simplification Method for Multiple Coastlines Based on the Hierarchical Triangulation Network Partition

For the current automatic coastline generalization method,only one-line element is considered separately,but the relationship between the nearby elements is not effectively considered.A synergistic simplification method for multiple coastlines based on the hierarchical triangulation network partition(HTNP)is proposed in this paper.Firstly,the constrained Delaunay triangulation is constructed to partition the regions that can be simplified.Then,a hierarchical binary tree model to structure the morphological characteristics of the above several coastlines and the spatial proximity between different coastlines is constructed.Finally,the small curved and curved invisible parts of the coastline are deleted according to the visual constraints,and the narrow part between the coastline itself or the different coastlines is exaggerated appropriately,and the automatic simplification of the coastline is realized.The experimental results show that:①Relationships between the different coastlines are considered,and the shortcomings of considering the coastline separately are overcome;②Under the condition of the multiple coastlines in complex sea areas,the problem of collaborative simplification is solved,the quality of the coastlines are improved obviously,and the proposed method can be applied into more types of coastlines.

Characterization of some bacterial strains isolated from the Egyptian eastern and northern coastlines with antimicrobial activity of Bacillus zhangzhouensis OMER4

Marine microorganisms were considered to be important sources of marine bioactive compounds.The major objective of the study was to isolate and characterize bacteria with antimicrobial activities from the various marine environment of Egypt.In this respect,thirty-five bacterial isolates were recovered from sediment samples collected from different spots along the Egyptian Red Sea coastline and Alexandria coastline during the summer season of 2017 and 2018.According to the morphological,physiological,and biochemical characteristics,the bacterial isolates were clustered into 13 groups designated as A,B,…,M.And,14 Gram-negative and 21 Grampositive bacteria were determined.The isolated bacterial strains were screened for their potentiality for antimicrobial agent(s)production against ten indicator strains.Strain Mo13 was showed high antimicrobial activity against all empirical strains.Subsequently,the most promising marine bacterial isolate with code MO13 was identified as Bacillus zhangzhouensis OMER4 according to the phenotypic characterization through morphological,physiological,and biochemical tests as well as genotypic characterization through the 16 S rDNA technique.The bioactive components were extracted with ethyl acetate,then analyzed using GC-MS and the substantial component was recognized as phenol,2,4-bis(1,1-dimethyl ethyl).

Are flight paths of nocturnal songbird migrants influenced by local coastlines at a peninsula？

By recording nocturnally migrating passerines with tracking radar we have investigated how coastlines affect the migrants＇ flight paths. Birds could use coastlines as an orientation aid or as a reference cue to compensate for wind drift while mi- grating. However, on the small scale of Falsterbo Peninsula in southern Sweden, we found very little effect of coastlines on migrants flight paths, irrespective of altitude. We tracked 2 930 migrants in three autumn and two spring seasons, at altitudes from 60 up to 3 000 meters. We compared tracks of migrants flying in three different areas, which correspond to the three main coastlines, and can demonstrate that the orientation of the tracks did not differ in a way consistent with the coastlines between the areas in autumn, and showed only a slight effect in spring. This is in accordance with earlier infrared device monitoring in Falsterbo, but contrary to earlier visual observations. It supports the view of nocturnally migrating passerines as mainly broad-front migrants. Even though the coastlines on the scale of the peninsula affected the flight paths very little, it is possible that the coastline has an effect on a larger regional scale, by migrants avoiding long sea crossings and thereby being funneled towards the peninsula, but this remains to be investigated [Current Zoology 60 （5）： 660-669, 2014].

Landsat Image-Based Spatiotemporal Variation Analysis of Erosion and Deposition off the Qingshuigou of the Yellow River Delta from 1984 to 2021

Owing to climate change and human activity,the Qingshuigou of the Yellow River Delta(YRD)has undergone dynamic changes in erosion and deposition.Therefore,studying these changes is important to ensure ecological protection and sustainable development.In this study,the trend of erosion-deposition evolution in the Qingshuigou was investigated based on 38 coastline phases extracted from Landsat series images of the YRD at one-year intervals from 1984 to 2021.The periodicity of the scouring and deposition evolution was also analyzed using wavelet analysis.Results showed that the total area of the Qingshuigou was affected by deposition and erosion and that the fluctuation first increased and then decreased.The total area reached a maximum in 1993.The depositional area first increased and then decreased,whereas the overall erosion area decreased.Deposition and erosion areas showed periodic changes to some extent;however,the periodic signal intensity decreased.Furthermore,factors including channel morphological evolution and variations in water and sediment discharge affect the spatiotemporal dynamics of erosion and deposition processes.The application of nonconsistency tests finally revealed that deposition area and flushing magnitude exhibited non-stationarities,which are potentially attributed to impacts from climatic change drivers.

Spatial and temporal variations of coastlines in northern China （2000-2012）

This study examined the spatial distribution of the continent coastline in northern China using remote sensing and GIS techniques, and calculated the fractal dimension of the coastline by box-counting method, with a time span from 2000 to 2012. Moreover, we ana- lyzed the characteristics of spatial-temporal changes in the coastline＇s length and fractal di- mension, the relationship between the length change and fractal dimension change, and the driving forces of coastline changes in northern China. During the research period, the coast- line of the study area increased by 637.95 km, at a rate of 53.16 km per year. On the regional level, the most significant change in coastline length was observed in Tianjin and Hebei. Temporally, the northern China coastline grew faster after 2008. The most dramatic growth was found between 2010 and 2011, with an increasing rate of 2.49% per year. The fractal dimension of the coastline in northern China was increasing during the research period, and the most dramatic increase occurred in Bohai Rim. There is a strong-positive linear relation- ship between the historical coastline length and fractal dimension （the correlation coefficient was 0.9962）. Through statistical analysis of a large number of local coastline changes, it can be found that the increase （or decrease） of local coastline length will, in most cases, lead to the increase （or decrease） of the whole coastline fractal dimension. Civil-coastal engineering construction was the most important factor driving the coastline change in northern China. Port construction, fisheries facilities and salt factories were the top three construction activi- ties. Compared to human activities, the influence of natural processes such as estuarine deposit and erosion were relatively small.

Heavy metal pollution assessment in marine sediments in the Northwest coast of Sabah,Malaysia

Heavy metal contents along the Northwest coast of Sabah were determined to interpret the pollution level in the marine sediment. The metal abundance is regulated by the physico-chemical properties such as the average sediment pH(7.82, 9.00 and 8.99), organic matter(0.62%, 1.60%, and 2.27%), moisture content(25.00%, 29.70%, and 15.00%) and sandy texture in Kota Belud, Kudat and Mantanani Island,respectively. The major elements show Ca>Fe>Mg>Al>Mn for all study sites, while the heavy metals show Ni>Cr>Zn>Cu>Co>Pb, Cr>Ni>Zn>Cu>Pb>Co and Zn>Pb>Cr>Ni, for Kota Belud, Kudat and Mantanani Island, respectively. The pollution degree of heavy metals was evaluated by using the Sediment Quality Assessment(SQA). The SQA parameters indicated none to moderate pollution in Kota Belud that shows Class 0, Class 1 and Class 2 pollution. The parameters also indicated none to low pollution in Kudat and Mantanani Island that show only Class 0 pollution. The enrichment factor(EF) suggested minor to moderately severe metal enrichment by anthropogenic sources in Kota Belud, whereas only minor enrichment in Kudat and Mantanani Island. The modified pollution degree(MCD<1.5) and pollution load index(0 PLI<1) indicating only low pollution level in the marine sediments for all study sites. The objectives of this study are:(1) to determine the physico-chemical parameters of sediments,(2) interpret the heavy metal contents and(3) evaluate the sediment quality.

Coastline changes and tidal current responses due to the large-scale reclamations in the Bohai Bay

China’s Bohai Bay has experienced large-scale land reclamation since 2000.These reclamation projects create a nearshore ecological imbalance and shift sediment transport by changing the tidal current.However,these tidal current changes are not comprehensively understood.In this paper,the coastline changes in Bohai Bay due to reclamation are investigated and the responses of the tidal current are calculated through numerical methods.The results show that the coastline length of the bay increases by more than 500 km from 2000 to 2015 with the largest reclamation rate of 150.9 km^(2)/a.Consequently,the current velocity changes with an uneven distribution near the reclamation due to construction masking and dike protrusion.The tidal symmetry also changes in most nearshore areas,with opposite variations in the current velocity at peak flood and ebb tide.In addition,the tide direction deflects to bypass the reclamation and is usually consistent with the coastline.Harmonic analysis of the dominant M2 tidal constituent shows that the range of the reciprocating current is widely extended.The total influence of the reclamation can reach the-8-m isobaths in Bohai Bay.Changes in the tidal current are the main causes of water environment deterioration.Therefore,the arrangement and structural optimization of reclamation projects should be considered in the future.

Prediction of the flooding area of the northeastern Caspian Sea from satellite images

Studying the dynamic changes in the coastline of the northeastern Caspian Sea is significant since the level of the Caspian is unstable,and the coastline change can cause enormous damage to the ecology,economy,and population of the coastal part of Kazakhstan.In this work,we use remote sensing and Geographic Information System(GIS)technologies to study the changes in the coastline of the northeastern Caspian Sea and predict the extent of flooding with increasing water levels.The proposed methodology for creating dynamic maps can be used to monitor the coastline and forecast the extent of flooding in the area.As a result of this work,the main factors affecting changes in the coastline were identified.After analyzing the water level data from 1988 to 2019,it was revealed that the rise in water level was observed from 1980 to 1995.The maximum sea level rise was recorded at-26.04 m.After that,the sea level began to fall,and between 1996 and 2009,there were no significant changes;the water level fluctuated with an average of-27.18 m.Then,a map of the water level dynamics in the Caspian Sea from 1988 to 2019 was compiled.According to the dynamics map,water level rise and significant coastal retreat were revealed,especially in the northern part of the Caspian Sea and the northern and southern parts of Sora Kaydak.The method for predicting the estimated flooding area was described.As a result,based on a single map,the flooding area of the northeast coast was predicted.A comparative analysis of Landsat and SRTM data is presented.

Monitoring and Quantification of Carbon Dioxide Emissions and Impact of Sea Surface Temperature on Marine Ecosystems as Climate Change Indicators in the Niger Delta Using Geospatial Technology

The Niger Delta marine environment has experienced a series of environmental disasters since the inception of oil and gas exploration,which can be attributed to climate change.Carbon dioxide(CO_(2))emissions and sea surface temperature(T)ties associated with burning fossil fuels,such as gas flaring,vehicular traffic,and marine vessel movement along the sea,are increasing.Using data extracted from the NASA Giovanni satellite’s Atmospheric Infrared Sounder(AIRS)and Moderate Resolution Imaging Spectroradiometer(MODIS),this study mapped the carbon footprint and T along the coastline into the deep sea from 2003 to 2011,using ArcGIS software.The spatial distribution of CO_(2) and T concentrations determined by the inverse distance weighting(IDW)method reveals variations in the study area.The results show an increase in the quantity of the mean tropospheric CO_(2) from July 2003 to December 2011,from 374.5129 ppm to 390.7831 ppm annual CO_(2) emissions,which also reflects a continuous increase.The average Monthly sea surface temperature had a general increasing trend from 25.79℃ in July 2003 to 27.8°C in December,with the Pearson correlation coefficient between CO_(2) and T indicating 50%strongly positive,20%strongly negative,20%weakly positive,and 10%weakly negative.CO_(2) levels,like temperature,follow a seasonal cycle,with a decrease during the wet season due to precipitation dissolving and plant uptake during the growing season,and then a rise during the dry season.Carbon capture and storage technologies must be implemented to benefit the marine ecosystem and human well-being.

Tsunami Hazard Assessment on Qatar Coastline from Makran Earthquakes Considering Tidal Effect and Coastal Landslides Scenarios

To assist the analysis of tsunami hazards for Qatar coastal areas were using numerical model. By Tsunamis waves created from submarine earthquakes of magnitude of (Mw) 8.6 and 9.0 in Richard scale along the Makran Subduction Zone (MSZ) as well as coastal landslides with soil volume of 1.25 to 2.0 km3 along Iranian coast inside the Arabian Gulf is considered. TUNAMI-N2KISR model (Al-Salem) was applied in this study to predict the tsunami propagation and magnitude of Tsunami induced wave heights. The model adopts to solve shallow water equations describing nonlinear long-wave theory. The model also incorporate tidal effect inside the Arabian Gulf as a tsunami travel time from Makran Subduction to Qatar coastline takes more than 9 hours with the tidal range of about 1.6 m during Spring Tide event. For coastal landslides, tsunami generation was simulated using a two-layer numerical model, developed by solving nonlinear long-wave equations. Two-layer model was used to determine initial wave deformation generated by a landslide case. Then TUNAMI-N2KISR was use to simulate tsunami wave propagation. Tsunami waves from landslide scenario arrived after 2.5 - 3 hr with maximum tsunami amplitudes along coasts of Ras laffan-Qatar were 0.8 to 1.0 m. Incorporation of ocean tide is found to impose some small effect on tsunami amplitude at Qatar coastline and nearby areas for the Mw 9.0 earthquake due to small tidal range in this area. In addition, it is found that the tsunami arrival time has become shorter.

Island instantaneous coastline extraction based on the characteristics of regional statistics of multispectral remote sensing image

This study adopted IKONOS remote sensing images and selected spectral characteristic areas, through regional pixel statistics and calculating weight coefficients of each band, processed the images with the spectral normalized method, which made the features of islands, land and water features more obviously in the images. On this basis, the OTUS was used to determine the optimal segmentation threshold, and the normalization image binarization was made, thus the island coastline was extracted. This method used the characteristic curve method to separate the land and water, obtained the binarization images and maintained the original edge effectively. The coastline that was extracted by Binary Morphology was continuous, reliable and high signal-to-noise ratio. The results showed that this method could extract the coastline fast, simply and effectively, which had the practical value.

Research on the Model of Coastline Demarcation and Management

The coastline demarcation and announcement models in China are outlined in this paper. The issues related to the coastline revision system, coastline zoning, coastline usage and the coastline information management are put forward. The concreted research and discussion on these issues are made which are valuable for the coastline management in our country.

Evolution of Yellow River Delta Coastline Based on Remote Sensing from 1976 to 2014, China

Coastal regions are threatened by natural processes, such as erosion driven by storm surges and the effect of jetties, as well as by human behavior. The coastline of the Yellow River Delta(YRD) was monitored using the general high-tide line method, which combines Remote sensing(RS) and geographic information system(GIS) technology, using multi-spectral scanner(MSS), thematic mapper(TM), and enhanced thematic mapper plus(ETM+) images of the YRD from 1976 to 2014 as a data source. The results demonstrated that the shape and length of the YRD coastline has changed dramatically since 1976. The course of the Diaokouhe channel has resulted in mainly inland erosion in the north, and is primarily marine erosion; therefore, it was termed an erosion-type estuary. However, the coastline of the Qingshuigou course has moved seaward, demonstrating an accretion stage, and was therefore termed an accretion-type estuary. The coastline advanced forward before 1997 and shrank after 2003 in the southern part of the river mouth, which was due to the shift in the river mouth in 1996. It has continually extended outward in the northern part of the river mouth from 2003 onward. The coastline in the southern part of the river mouth has moved randomly, with the occurrence of both erosion and sedimentation caused by land reclamation and sea wave intrusion. In most cases, the coastline has extended offshore, especially in the northern part of the river mouth. The YRD coastline has changed frequently and rapidly from 1992 to 2014. The river mouth channel, river water and sediments, and precipitation were the major factors affecting the YRD. The YRD coastline was mainly in an accretion stage during flow periods. The erosion rate decreased and tended to be stable during a dry period. The coastline was basically stable when dry periods occurred over a long period. The location of Yellow River ports and sea erosion were the main factors driving coastline changes. The coastline was mainly influenced by the flow path of the Yellow River, with recent human activity also becoming a factor.

Effect of water-sediment regulation and its impact on coastline and suspended sediment concentration in Yellow River Estuary

Implementation of the water-sediment regulation(WSR) scheme, mainly focused on solving the sedimentation problems of reservoirs and the lower reaches of the Yellow River, has inevitably influenced the sediment distribution and coastal morphology of the Yellow River Estuary.Using coastline delineation and suspended sediment concentration(SSC) retrieval methods, this study investigated water and sediment changes,identified detailed inter-annual and intra-annual variations of the coastline and SSC in the normal period(NP: 1986-2001, before and after the flood season) and WSR period(WSRP: 2002-2013, before and after WSR). The results indicate that(1) the sedimentation in the low reaches of the Yellow River turned into erosion from 2002 onward;(2) the inter-annual coastline changes could be divided into an accretion stage(1986-1996), a slow erosion stage(1996-2002), and a slow accretion stage(2002-2013);(3) an intra-annual coastline extension occurred in the river mouth in most years of the WSRP; and(4) the mean intra-annual accretion area was 0.789 km^2 in the NP and 4.73 km2 in the WSRP,and the mean SSC increased from 238 mg/L to 293 mg/L in the NP and from 192 mg/L to 264 mg/L in the WSRP.

On Spatial Fractal Character of Coastline——A Case Study of Jiangsu Province,China

According to the fractal theory, the spatial fractal character of coastline is preliminarily discussed on the basis of GIS in this paper. Two aspects are considered: one is the length demarcation of coastline with different scales, and the other is the confirmation of existence of the fractal character on different boundaries of tidal flats. Finally, some significant conclusions are drawn: (1) The coastline of Jiangsu Province has the fractal character and its dimension is 1.0696. (2) It conforms to the exponential correlation between different lengths (L) of coastline and scales (k). I; conforms to the formula lgL(k) = -1.029 lgk+ 2.9544 in the continental coastline of Jiangsu province. (3) Different boundaries of a tidal flat have fractal characters, and different fractal dimensions indicate different comparative intensities of erosion and deposition on the tidal flat. (4) The reciprocity between land and sea may affect the value of fractal dimension of a coastline, just as the lithology, substantial constituent and geological structure do.

An intelligent coastline interpretation of several types of seacoasts from TM/ETM+ images based on rules

A coastline is defined as the average spring tide line. Different types of seacoast, such as sandy, silty, and bio- logical coast, have different indicators of interpretation. It is very difficult to develop a universal method for interpreting all shorelines. Therefore, the sandy, the silty, and the biological coast are regarded as research objects, and with data mining technolog,found the rules of interpretation of those three types of coastlines. Then, an intelligent coastline interpretation method based on rules was proposed. Firstly, the rules for ex- tracting the waterline in Landsat TM/ETM＋ （Thematic Mapper/Enhanced Thematic Mapper Plus） imagery were discovered. Then, through analyzing the features of sandy, silty and biological coast, the indicators of interpreting different types of shoreline were determined. According to the indicators, the waterline could be corrected to the real coastline. In order to verify the validity of the proposed algorithms, three Landsat TM/ETM＋ imageries were selected for case studies. The experimental results showed that the proposed methods could interpret the coastlines of sandy; silty, and biological coasts with high precision and without human intervention, which exceeded three pixels.