Stormy Waves Research Articles

Biomonitoring of metal contamination in estuarine ecosystem using seagrass.

Metals concentrations (As, Cd, Cu, Hg and Pb) in seawater, sediment and the seagrass (Enhalus acoroides) were analysed at Pulai River estuary, Johor Straits, Malaysia. In this research, Enhalus acoroides was used in order to find it’s efficiency in up taking metals with a role in phytoremediation. Seawater, sediment and Enhalus acoroides samples were collected, and data of Pearson’s correlation coefficients were analysed using SPSS 16 software. Results show that lead levels were the highest metal content in Enhalus acoroides (202 ± 102 μg/gDW), seawater (268 ± 190 μg/L) and sediment (248 ± 218 μg/gDW), compared to other metals. There was a positive correlation for metal concentrations between Enhalus acoroides and sediment, but no correlation was found between Enhalus acoroides with seawater at estuarine area may be caused by inconsistent metal concentrations in seawater due to the influences of tidal changes and stormy waves. This indicates that Enhalus acoroides is a species possessing the capabilities to uptake metals from sediment, and suitable to act as both a phytoremediator and biomonitor in estuarine ecosystems due to sharp sensitivity to variation in the environment.

MORPHOLOGY OF THE BLACK SEA COAST BETWEEN LAGERNAYA SPIT AND THE OCHAKOVSKIY CAPE

The studied sea coast settle down between Berezansky strait and Ochakovskiy Cape with long is 16 km. The coast represented the abrasion site (active clayey cliff) and the accumulative site (the sandy Lagernaya spit). In nature the cliff height is about 25 m, and average rate of abrasion cliff retreat 2.5 m/year. The Lagernaya spit has length about 6 km, height to 2 m and width to 150-200 m. It is linked with active cliff and displaced towards liman. Nowadays Lagernaya spit is in a degradation stage by impact of anthropogenous factor. Beaches are disappear gradually. The coast is built strongly up. The submarine slope is shallow up to 0.001-0.005. As a result, the wave factor is low, and at the same time impact of storm-surges is heightened. Artificial relief forms wide distributed as a hydrotechnical constructions that are sea-walls, jetties, moorings, and bearms, groins, sea-port dippers, navigate canals too located. All of them are blocking abrasive sources of shore sediments in coastal zone, and its are aggravating the sediment deficit and increase destructive tendencies of nature evolution. Around of Kinburn Strait typical is relative the sea level rise. During past 15 years the average rise value is up to 9,8 mm/year, and as a result this process lead to submerging of Lagernaya Spit, Ochakovskiy Cape terrace and Kinburn Peninsula. Also, rising of underground water, activization of landslides, salting waters in Dnepr and Southern Bug mouths, reinforcement of stormy waves development take place in investigated coastal region.

Maritime disputes in East Asia and the Pacific region – the stormy waves of international relations

1. Opinions expressed by the author are his own views and they do not re do not reflect in any way the ect in any way the official policy or position of the Baltic Defence College, or the governments of Estonia, Latvia or Lithuania. Google Scholar

Numerical simulation and inversion of offshore area depth based on x-band microwave radar

A detection method of offshore area depth utilizing the x-band microwave radar is proposed. The method is based on the sea clutter imaging mechanism of microwave radar, and combined with dispersion equation of the liner wave theorem and least square method (LSM), consequently get the inversion results of water depth in the detected region. The wave monitoring system OSMAR-X exploited by the Ocean State Laboratory, Wuhan University, based on a microwave radar has proven to be a powerful tool to monitor ocean waves in time and space. Numerical simulation and inversion of offshore area depth are carried out here; since JONSWAP model can give description of stormy waves in different growth phase, it is suitable for simulation. Besides, some results from measured data detected by OSMAR-X x-band radar located at Longhai of Fujian Province, China, validates this method. The tendency of the average water depths inferred from the radar images is in good agreement with the tide level detected by Xiamen tide station. These promising results suggest the possibility of using OSMAR-X to monitor operationally morphodynamics in coastal zones. This method can be applied to both shore-based and shipborne x-band microwave radar.

Impact of Dynamic Morphology Change on Storm Surge Disaster Risks along the Meghna Estuary

This study focuses on the impact of morphological changes on storm surge disaster risks in coastal areas around the Meghna estuary of Bangladesh. Long term meso scale features of bathymetry change in the target area are first investigated through analysis of shoreline profiles extracted from satellite images. More than 40 shoreline profiles within the past 40 years are extracted from satellite images. Difference of the tidal phaseduring the period when satellite image was acquired is taken into consideration. Based on Cyclone Sidr of 2007, several model cyclones are selected for numerical computations of storm surges around the Meghna estuary. Besides shoreline profiles, ground elevations of the newly accreted lands arealtered in the computation to compare the inundation area, inundation depth and hydrodynamic forces in each case. Results show that(i) 10 to 20 years of morphology change could alter local inundation height of the order of meters; (ii) elevation of newly created land affectsthe inundation time of surrounded area and 3m higher accreted land tends to shorten the inundation time up to 100minutes; (iii) newly created land reduces the damage levels behind itself while it increases the inundation area and height in the area located seaside of itself and (iv) newly created land significantly reduces the stormy waves and hydrodynamic forces especially in the area behind itself.

Observation of Stormy Wave Fields by X-band Radar

Observation of Stormy Wave Fields by X-band Radar

台風Haiyanに伴うレイテ島およびサマール島における高潮・高波特性の分析

台風Haiyanに伴うレイテ島およびサマール島における高潮・高波特性の分析

The Quest for Identity in Sayed Kashua's <em>Let It Be Morning</em>

Like a school of dolphins, most Israeli Arabs have lost their way deep in a stormy sea. One wave throws them up; another pushes them down to the bottom of the sea. They struggle day and night for their identity. They keep swimming in that stormy sea wishing for the sunny day to come, thus enjoying the glory of the sea; but the sea refuses to accept them, and the stormy waves insist to throw them out to the shore, where they get suffocated and find their death.1

The Material Mechanism Analysis of Airliner Forced Landing onto Water

The paper concentrates on the material mechanism analysis of airliner landing onto water in slide decelerating stage. According to the solid material, the difference equation is constructed to find the posture of airliner with different angles Our numerical results show that the impact of stormy wave may make airliner out of balance, impact acceleration is inversely proportional to the sliding distance, .

Assessment of fish spatial distribution and biomass in Lake Taihu using hydroacoustic method

利用BioSonics DT-X科学回声探测仪(208 kHz)在太湖2011年开捕前的8月对东部和北部湖区的鱼类进行了走航式水声学调查,并结合地理信息系统(GIS)模型对调查湖区的鱼类大小组成、空间分布和资源量进行了评估.结果表明,调查湖区的鱼类平均目标强度(目标鱼类对声波的反射能力)为-51.85±0.02 dB,平均体长在6 cm左右,体长范围为2.35~89.33 cm,不同区域间的鱼类目标强度差异性显著,表明不同区域间鱼类大小存在差异,其中鱼类的最小平均目标强度(-53.94±0.10 dB)出现在洞庭东西山之间,最大平均目标强度(-50.27±0.14 dB)出现在光福湾.调查湖区的鱼类密度在0.43~3.90 ind./m³之间,采用地理信息系统(GIS)对调查湖区进行建模得到鱼类密度均值为2.27±0.57 ind./m³,不同区域间鱼类密度差异性显著,鱼类密度在敞水区较高.基于建模的栅格化数据评估调查湖区鱼类资源量约为5.3×10⁹ind.,其中目标强度在-45 dB(体长约13 cm)以下的鱼类占98.49%.本文对水声学方法在大型浅水湖泊中的应用进行了初步探索,水声学方法可在一定程度上突破传统鱼类资源调查方法在较大空间尺度上的局限性,但在调查时易受风浪、水生植物、船速的影响.;Before the fishing of Lake Taihu,a mobile hydroacoustic survey was performed in eastern and northern of Lake Taihu in August of 2011,with using BioSonics DT-X scientific echo-sounder (208 kHz).Combining Geographic Information System (GIS) model,then fish size component,spatial distribution and biomass are assessed.The results show that the mean target strength (acoustic reflectivity of target fish) in the surveying lake areas is-51.85 ± 0.02 dB and the mean length is about 6 cm,ranging from 2.35 to 89.33 cm.The fish target strength in different areas is significantly different,which means there is significant difference of fish size,with the minimum mean target strength (-53.94 ± 0.10 dB) in the middle of Dongshan Island and Xishan Island and the maximum mean target strength (-50.27 ± 0.14 dB) in Guangfu Bay.The mean fish density is 2.27 ± 0.57 ind./m³, ranging from 0.43 to 3.90 ind./m³ in all survey areas,where a high fish density occurred in open water zone.Based on the raster data gained from fish distribution GIS model,the total amount of fish mantissa biomass are estimated to be 5.3×10⁹ ind.,in which the fish with target strength lower than-45 dB (length about 13 cm) is 98.49%.The present study provided a preliminary application of the hydroacoustic method and performed in big shallow lake for fish resources investigation.This can break through the limitations of the traditional investigation methods for fish resource assessment on large spatial scales,to a certain extent.The application is still influenced by stormy waves,aquatic plants and speed.

Cotton Mather and Boston's “Seafaring Tribe”

This essay tells the compelling story of Cotton Mather's struggle to ride the stormy waves of colonial Boston's rise as an Atlantic port by focusing his ministerial and intellectual energies on a growing and volatile seafaring population. Seafarers' reactions to his efforts produced a complex, at times paradoxical, relationship.

The Posture of Airliner Forced Landing onto Water in Slide Decelerating Stage

The paper concentrates on the posture of airliner landing onto water in slide decelerating stage. For different angles, the difference equation is constructed to find the posture of airliner by using solid-fluid coupling, momentum conservation, motion equation and pressure drag. The results show that impact acceleration is inversely proportional to the sliding distance, the impact of stormy wave can make airliner out of balance, and course angle is 80 can minimize the chance of rollover.

WAVE BREAKING AND WAVE SETUP OF ARTIFICIAL REEF WITH INCLINED CROWN

INTRODUCION
 The beach protection facilities are required in some situations to harmonize with coastal environments and utilizations(National Association of Sea Coast,2004). This study investigates some hydraulic functions of proposed multipurpose artificial reef which has an inclined reef crown. The reef is expected to protect beaches against storm waves, and also facilitates the surfing activities under mild wave conditions. The forced wave breaking on the reef sometimes causes a mass transport and wave setup. This study focuses on the following hydraulic characters to clear the efficiencies of proposed artificial reef with inclined crown. 1) Wave energy dissipation by the reef, 2) Generation of suitable wave breakers for surfing, 3) Wave setup behind the reef.
 
 HYDRAULIC EXPERIMENT SETUP
 A series of hydraulic experiments were carried out with using a two-dimensional wave flume. The model scale was assumed 1/30. Three kinds of cross sections were employed as the model of artificial reef (Fig.-1). Both Case-A and Case-B have the inclined crown. The cross section of Case-C, which has a flat crown, is set as a typical cross section of conventional artificial reef. The reef length of Case-A is the same as that of Case-C, and Case-B is double the length of Case-A. Two different submerged depths of crown, hc=2cm and 5cm, were set in the experiments. In Case-A and Case-B, their submerged depth of crown, hc, were defined as the minimum depth at the onshore edge of the crown. The incident wave heights were changed at 1cm intervals from 4cm to 9cm, and the periods were also chanced at 1 sec. intervals from 1 sec. to 2.4 sec. for each wave height. 
 
 SUMMARY OF RESULTS
 The energy flux ratio of transmitted waves in Case-B shows similar values in Case-C under the stormy wave conditions in the case of hc=2cm. The longer reef shows favorable characters in dissipating wave energy as well as in maintaining a wider breaker zone on its crown. On the other hand, the transmitted energy flux in Case-A become slightly higher than that in Case-C. The inclined shape of the reef crown closely relates to both the type of wave breakers and the generation of higher order waves.
 Wave breakers observed in Case-A and Case-B are almost Plunging breaker or Collapsing breaker, and these breakers are suitable for surfing(Walker, et.al.,1972). In Case-C, on the other hand, most incident waves break at the offshore edge of the crown with backwash(Fig.-2). This means that the slope on the reef crown play an important roll in generating suitable breakers for surfing. Type of wave breakers on the inclined reef were summarized by surf similarity parameter(Battjes,1974).
 Fig.-3 shows the normalized wave setup behind each reef. The wave setup differs depending the reef sections. Case-A and Case-B check the wave setup effectively in comparison with Case-C. This excellent checking effect can be observed in the wide range of incident wave height and wave period. Through a series of hydraulic experiments, it is cleared that the difference of wave setup observed behind the reefs relates to the wave breaker type and wave breaker point on the reefs.

Morfodinâmica e a estabilidade da praia de Piratininga, Niterói (RJ)

The Piratininga beach, some 2,5 km long and one of the most popular in Niteroi, has undergone major destruction of its sidewalks and concrete wall because of stormy waves. Thirty topographic profiles and twenty four samples were collected over five years to help resolve this problem and were compared with data collected in the 1970’s and 1990’s. The present wave regime is as follows: today normal moderate to weak waves come from the southeast and stormy waves come from the southwest and south. This produces the greatest variability in the beach profile at its west end. Similarly, the sands are relatively poor sorted at the west end of the beach. Comparison with profiles from the 70’s and 90’s shows no significant change over the last 30 years. Thus, the conclusion is that the beach has been in equilibrium with its wave regime for at least 30 years. This tell us that the engineering structures should either be improved along the beach or preferentialy be removed and let the original profile return.

Sedimentation and the Role of Sediment Flush Discharge in the River Mouth of the Magome River Flowing through Coastal Sand Dune

This paper investigates the mechanisms of sediment movements under waves and currents in the river mouth of the Magome River. Special focus is paid on a function of “sediment-flush discharge” which was uniquely introduced to the Magome River to increase the river discharge and mitigate sedimentation problems around the river mouth. Analysis of various data showed that sudden and severe sedimentation is caused by overtopping of stormy waves while daily river discharge including sediment flush discharge flushes sediment in a more gradual manner. Numerical analysis was conducted to investigate quantitative effects of sediment flush discharge and showed that flexible control of sediment flush discharge adjusting to the sedimentation conditions should reduce the risk of inundation.

Example and Characteristic of Disaster induced by Accidental Wave Load

The performance design code has been proposed in the coastal and harbor structureconstruction. In the new designcode, the design wave with a return period employed in the former design method is defined as the variable wave load. Meanwhile the accidental wave load that occurs in a low probability but causes a serious damage is considered in thenew design code to secure the safety and reparability of the structures. The specification of accidental wave load, however, is not clearly indicated in the new code. This paper describes the characteristics of structure damages caused bythe recent stormy waves with long period swells and proposes the application of such waves as the accidental waveload. The long period swell becomes the critical load when the breakwaters are constructed in the surf zone.

Study on behaviors of wave-dissipating concrete blocks of submerged breakwater around the Fukui Port using GPS

Stabilization of the seawalls is required for protecting the important facilities along the coast of the Fukui Port. Since 2004, Ministry of Land, Infrastructure and Transport has commenced the projects for improvement of the existing seawalls for scouring and liquefaction protection, and for construction of new submerged breakwaters. Construction of “two-crested submerged breakwaters, ” which have two parallel crests along the coast, was newlycommenced in 2006. The ministry realized that stability of the submerged breakwater needs to be examined because the submerged breakwater experiences winter stormy waves while the construction of the breakwater is not yetcompleted, i. e., the total length of the breakwater is 45m compared to the designed total length of 200m. This paper presents a survey result of location of concrete armor blocks for the submerged breakwater on partial completion with using Real-Time-Kinematic GPS.

Observation of a Stormy Wave Field with X-Band Radar and its Linear Aspects

An X-band nautical radar system was employed to observe the wave field during a storm around the research pier HORS in Hasaki, Japan. The radar system provides instantaneous distributions of wave crests in the near-shore region, with image sequences comprising a clear spatial and temporal variation of the wave pattern. The spectra of radar echo signals and water surface elevations from wave gauge records were compared, and a relatively high coherence for a particular bandwidth was observed. A sequence of radar images was filtered at the dominant frequency, which was used to estimate the wavenumber distribution of the refraction field. The Fast Fourier Transform (FFT) and Maximum Entropy Method (MEM) were used to estimate the wavenumbers. The estimated wave angles were then compared with linear refraction analyses. The water depths along the pier were also estimated using the linear dispersion relationship and compared with the surveyed depths. The linear estimates of hydrodynamic parameters during the passage of the storm are presented in this paper to demonstrate the potential of radar measurements in capturing essential characteristics of coastal dynamics.

Advance in the study on phosphorus speciation, transformation and its potential ecological effects in Chinese lakes

天然水域,尤其是富营养的浅水湖泊,沉积物中磷的释放是蓝藻水华发生、形成和持续生长的重要因素.分析沉积物中磷的赋存形态转化及其潜在生态效应,有助于理解沉积物中磷的迁移转化过程及其与湖泊富营养化之间的关系.本文综述国内湖泊水域中磷的主要形态、来源和转化过程以及其生物有效性的研究进展.重点讨论了近5年来中国东部浅水湖泊沉积物磷的形态分析、转化和生物有效性评估的现状,以及沉积物中磷形态与浅水湖泊富营养化之间的潜在联系.;Release of phosphorus from sediment of natural waters, especially from those shallow lakes, are essential process in the growth and development of algae bloom. Studies on species transformation and changes in bioavailability will be helpful in understanding geochemical cycling of phosphorus in lakes and its relation to lake eutrophication. This paper summarized the recent research progresses on phosphorus speciation, transformation, phosphorus cycling in Chinese lakes, and the relevant changes in bioavailability. Recently, special attention was given to issues such as different species in sediments in eastern China shallow lakes because there were only a few works on the lakes in the west, south and north of China. Relevant research was also less found on the brackish lakes in the plateaus or lagoons in the estuarine and coastal zones. In addition, it is a pity that no work could make a breakthrough on the methods of phosphorus fractionation. There was a little advance in the study on the transformation of phosphorus species, the assessment of phosphorus release risk and its bioavailability. For example, the pattern of phosphorus release from different types of sediments in response to pH changes was unveiled; the approaches for laboratory and in situ measurements of bioavailable forms of phosphorus were developed, as well as the relationship between acid soluble organic phosphorus species and eutrophication were proposed. In a eutrophic shallow lake, there is an interaction relationship between algal blooms and internal phosphorus release. However, this interaction is well related to human disturbance and influenced by some natural factors, e. g. hydrodynamic processes and stormy waves. Much beneficial exploration was done on the phosphorus speciation, mobilization and transformation between sediment and water interface in many lakes in China, and a lot of hypothesises as well as new methods were also proposed in recent studies, but it still need more experimental data to testify.

Dinâmica sazonal e os efeitos das ressacas nas praias de Niterói/RJ

Beaches are important for the protection of the coastal region against stormy waves. Therefore, beach conservation is fundamental but, contrary to that, beaches and related environments in the sandy barrier are frequently modified by human activity. The aim of this work is to present observations carried on from 1991 to 2002, on the beach dynamics of Niteroi (RJ), as a response to seasonal stormy waves. Topographic profiles obtained on the beach and shoreface, pointed out that some parts of the beaches are more vulnerable to stormy waves activity and thus need special attention since problems with urban constructions already exist. These areas are the northwest extreme of Icarai, both extremes of Piratininga and the northwest and center of Camboinhas beach.