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1.
Establishment of numerical beach-litter hindcast/forecast models: an application to Goto Islands, Japan 总被引：1，自引：0，他引：1
This study attempts to establish a system for hindcasting/forecasting the quantity of litter reaching a beach using an ocean circulation model, a two-way particle tracking model (PTM) to find litter sources, and an inverse method to compute litter outflows at each source. Twelve actual beach survey results, and satellite and forecasted wind data were also used. The quantity of beach litter was hindcasted/forecasted using a forward in-time PTM with the surface currents computed in the ocean circulation model driven by satellite-derived/forecasted wind data. Outflows obtained using the inverse method was given for each source in the model. The time series of the hindcasted/forecasted quantity of beach litter were found consistent with the quantity of beach litter determined from sequential webcam images of the actual beach. The accuracy of the model, however, is reduced drastically by intense winds such as typhoons which disturb drifting litter motion. 相似文献
2.
Characteristics of drift and beaching of floating marine litter in the Japan Sea are examined numerically using the reanalysis data of the Japan Sea Forecasting System of Kyushu University. The residence time of model marine litter deployed uniformly over the surface of the Japan Sea strongly depends on the buoyancy ratio. However, almost all litter beaches or flows out through straits within 3 years. Experiments with inputs of litter imposed at large cities and the Tsushima Straits as well as river basins of the Japan Sea exhibit a good agreement with beach surveys with regard to country ratios of beached litter along the Japanese coast in cases of lighters. In a case of lighter, almost all lighters originating from Japan beach along the Japanese coast, while almost all lighters originating from a country surrounding the Japan Sea except Japan beach along the coast of that country and the Japanese coast. 相似文献
3.
This study has demonstrated a reliable method of quantifying the total mass of litter on a beach. It was conducted on Ookushi beach, Goto-Islands, Japan, and uses a combination of balloon-assisted aerial photography and in situ mass measurements. The total mass of litter over the beach was calculated to be 716 ± 259 kg. This figure was derived by multiplying the litter-covered area (calculated using balloon-assisted aerial photography) by the mass of litter per unit area. Light plastics such as polyethylene made up 55% of all plastic litter on the beach, although more work is needed to determine whether lighter plastics are transported to beaches more readily by winds and ocean currents compared with heavier plastics, or whether lighter plastics comprise a greater percentage of marine litter. Finally, the above estimates were used to calculate the total mass of metals released into coastal ecosystems via plastic litter on beaches. 相似文献
4.
In this study, an intertidal bar and trough system on the beach of Noordwijk, The Netherlands was monitored over a 15‐month period in order to examine the daily to seasonal sequential cross‐shore behaviour and to establish which conditions force or interrupt this cyclic bar behaviour. The beach morphology (bars and troughs) was classified from low‐tide Argus video images based on surface composition. From the classified images, time series of the landward boundary of the bar and of the trough were extracted. The time series of the alongshore‐averaged boundary positions described sawtooth motion with a period between 1 and 4 months, comprising gradual landward migration followed by abrupt seaward shifts. The abrupt seaward shift appeared to be a morphological reset induced by storm events, which lasted at least 30 h with a large average root‐mean‐square wave height (≥2 m) and offshore surge level (≥0·5 m), and a small trough (<20 m wide) in the pre‐storm beach morphology. The time series of the boundary positions exhibited very little longer (seasonal) scale variability, but somewhat larger smaller (daily) scale variability. The bar boundary was found to be more dynamic than the trough boundary. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
5.
A cobble beach (-6 diameter to -8 diameter) located on the South Wales coastline, UK, was studied over a three-month winter period to assess litter input levels. After total beach litter clearance, six surveys were conducted at consecutive spring tides which involved marking of previously unrecorded litter. The beach was soon inundated with debris, predominantly plastic beverage containers. Some marked litter was found to disappear from the beach surface, re-emerging weeks later which suggests that the potential for litter burial has been underestimated in litter research. Higher wave energies between surveys coincided with higher levels of previously unseen litter. These new inputs consisted of sea borne and exhumed litter. Items larger than the surrounding cobbles were found to work their way back to the surface of the beach after burial, smaller items remained buried. Pits dug into the cobble ridge confirmed the burial of mainly small items. 相似文献
6.
The Anxious Bay beach litter clearance is the longest running annual survey of ocean-based litter in Australia. It's remoteness from centres of human population and location (with respect to prevailing winds and currents) make it an ideal place for monitoring ocean or ship-based litter in Australia's southern oceans and particularly, the Great Australian Bight. Over the 1991-1999 period, a large but gradual decline in the amount of beach washed litter was recorded (with minor peaks recorded during the 1992 and 1994 surveys). Beach washed litter decreased by approximately 86%, from 344 kg recorded in 1991 (13.2 kg/km) to 49 kg in 1999 (i.e. 1.9 kg/km), reaching a maximum of 390 kg in 1992 (or 15 kg/km of beach). However, a sharp increase in litter was recorded in 2000 (i.e. 252 kg or 9.7 kg/km). This increase in litter yield in 2000 is probably due to stronger than average onshore surface flow (or Ekman Transport) in the western Eyre Peninsula and Bight region. Prior to the survey in 2000, the results appeared to indicate that ocean litter on Anxious Bay beach was beginning to level out at around 50-70 kg/year (i.e. 2-3 kg/km). As the beach surveys involve the assumption that the beach is completely cleared of litter, this may represent a baseline level for ocean-based litter in the region. The yields and type of litter collected from the annual survey indicates that the majority of litter washed ashore originates from commercial fishing activities within the Great Australian Bight. Most of the fishing-related litter was directly sourced to the Southern Rock Lobster Fishery (i.e. bait buckets, baskets, pots), the Great Australian Bight Trawl Fishery (i.e. codends, trawl nets) and the Southern Shark Fishery (i.e. monofilament gillnets and longlines). Between 1994 and 1999, large reductions were observed in the amount of bait straps (77% reduction), lobster bait baskets/buckets (86% reduction), nets/ropes (62% reduction) and floats/buoys (83% reduction). Significantly, fishing-related litter in the Bight has reduced at a slower rate than domestic litter. While the level of glass and soft plastics on the beach have both reduced by almost 93% (i.e. 103-7 kg and 119-8 kg, respectively), the level of hard plastics, has diminished at a slower rate, with reductions of only 75% (i.e. 122-30 kg). Some fisheries (i.e. rock lobster, Southern Shark Fishery) have shown marked reductions in fishing-related litter. This is probably due, to some extent, to significant reductions in fishing effort in the region, although this requires further investigation. The information from the Anxious Bay beach litter survey is crucial in monitoring trends in ocean litter in Australia's southern oceans and compliance with international litter regulations. While fishing-related litter remains the major source of ship-based or ocean litter in Australia's southern oceans, the continued reduction in ship-based litter since 1991 supports increasing compliance to MARPOL (Annex V) by commercial fisheries and shipping in the Great Australian Bight. While Australia participates in marine debris monitoring programs in the Antarctic (under CCAMLR), there is currently no national program or management framework to assess, manage and monitor ocean-based litter along Australia's coasts, and monitor compliance with MARPOL. Apart from the commitments under CCAMLR for Antarctic (and sub-Antarctic) marine environments, there are no other regional programs, guidelines or monitoring protocols or to assess and manage ocean litter in the Southern Ocean. 相似文献
7.
Low altitude remote-sensing method to monitor marine and beach litter of various colors using a balloon equipped with a digital camera 总被引：1，自引：0，他引：1
This study aims to establish a low-altitude remote sensing system for surveying litter on a beach or the ocean using a remote-controlled digital camera suspended from a balloon filled with helium gas. The resultant images are processed to identify the litter using projective transformation method and color difference in the CIELUV color space. Low-altitude remote sensing experimental observations were conducted on two locations in Japan. Although the sizes of the litter and the areas covered are distorted in the original photographs taken at various angles and heights, the proposed image process system is capable of identifying object positions with a high degree of accuracy (1-3 m). Furthermore, the color difference approach in the CIELUV color space used in this study is well capable of extracting pixels of litter objects of various colors allowing us to estimate the number of objects from the photographs. 相似文献
8.
Evaluating proxies for estimating subaerial beach volume change across increasing time scales and various morphologies 
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下载免费PDF全文 Proxies, such as changes in beach profiles and shoreline positions, are commonly used in management and research for estimating changes in subaerial beach volume; however, the accuracy of these proxies across increasing time scales and complex morphologies is unclear. Volume changes associated with along‐beach morphologic variability may not be captured well by changes in profiles, while volume changes associated with across‐beach morphologic variability may not be captured well by measuring shoreline change. This study assesses the impacts of morphologic variations, associated with beach cusps and nourishment material, on volume change estimates from profiles and shoreline change at 0.5 to 3.5 year time periods. Results indicate that profiles spaced ≥ 150 m apart and the shoreline‐change proxy will likely estimate volume change inaccurately over periods ≤ 1 year at beaches that are consistently eroding or accreting and contain cusps. However, over longer time periods (1–3.5 years), estimates of volume change from both proxies improved at those types of beaches. Volume changes at the edges of nourishment areas are not captured well by profiles. When the nourishment material is graded to a ramped morphology, which minimizes across‐beach morphologic variability, the shoreline‐change proxy does accurately estimate volume changes. Both proxies estimate volume changes inaccurately at beaches where volume changes oscillate between erosion and accretion on both short and long time scales because the magnitude of small‐scale changes in volume from the formation and erosion of morphologic features, such as cusps and berms, will always be similar to the longer‐term net volume change. This study suggests that decadal records of shoreline change, which are commonly developed using aerial photography, can be used to help identify the best proxy for estimating volume change; however, recent anthropogenic modifications that impact patterns of beach sedimentation, including nourishment, terminal groins, and inlet‐channel dredging, makes decadal records less useful. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
9.
Theodore R. Merrell 《Marine pollution bulletin》1984,15(10):378-384
Ten 1 km beaches on Amchitka Island, Alaska, were surveyed once annually in 1972–1974 and in 1982 to determine weights and numbers of fish-net fragments and other plastic litter items. Most litter was from Japanese and Soviet fishing vessels. Litter rapidly increased during 1972–74 (from 122 to 345 kg km?1 of beach) but decreased 26% by 1982 to 255 kg km?1. There was a 37% reduction in weight of trawl web on Amchitka beaches, and the number of gill-net floats declined 47%. The decrease in litter between 1974 and 1982, attributed to fewer trawlers and gill-netters fishing off Alaska, shows that marine litter could be rapidly reduced if disposal of litter at sea were restricted. 相似文献
10.
Marine litter prediction by artificial intelligence 总被引：1，自引：0，他引：1
Artificial intelligence techniques of neural network and fuzzy systems were applied as alternative methods to determine beach litter grading, based on litter surveys of the Antalya coastline (the Turkish Riviera). Litter measurements were categorized and assessed by artificial intelligence techniques, which lead to a new litter categorization system. The constructed neural network satisfactorily predicted the grading of the Antalya beaches and litter categories based on the number of litter items in the general litter category. It has been concluded that, neural networks could be used for high-speed predictions of litter items and beach grading, when the characteristics of the main litter category was determined by field studies. This can save on field effort when fast and reliable estimations of litter categories are required for management or research studies of beaches--especially those concerned with health and safety, and it has economic implications. The main advantages in using fuzzy systems are that they consider linguistic adjectival definitions, e.g. many/few, etc. As a result, additional information inherent in linguistic comments/refinements and judgments made during field studies can be incorporated in grading systems. 相似文献
11.
The aesthetic quality of fourteen beaches in the Firth of Forth, Scotland was surveyed between May and July 2002 using a protocol designed by the UK's National Aquatic Litter Group (NALG). Local authority beach cleaning regimes influence the amount of litter found on beaches. Frequent and thorough beach cleaning is necessary to maintain high aesthetic standards. Bathing and amenity beaches achieved higher aesthetic quality than non-bathing and non-amenity beaches. The aesthetic quality of rural and urban beaches was very similar. The NALG protocol appears more complicated to use than other beach litter surveys. However, the classification system generates results that are easily interpreted by the general public. Furthermore, the NALG protocol could be combined with coastal zone management plans as a useful environmental performance indicator. 相似文献
12.
Ten methods for sampling beach litter were tested on 16 beaches located around the Firth of Forth, Scotland in order to ascertain the effectiveness of the various methods. Both fresh and/or accumulated litter were sampled. Some methods were more effective for recording gross amounts of litter. Maximum litter counts could be obtained by surveying the top boundary of the beach (e.g. vegetation line, retaining wall, rocks). Lowest amounts were obtained by surveying one five metre wide belt transect from the vegetation line to the shore. Some bias towards highlighting particular litter types was shown by specific methods. It was concluded that there were advantages and disadvantages for each method and that the aims of the study would in the end determine the method. 相似文献
13.
Recent work at three contrasting sites in England and Wales has shown characteristics atypical of those frequently reported elsewhere. These differences are:
- (a) Taking each entire beach system there is no uniform trend of erosion or accretion, nor a progressive variation in beach elevation or volume alongshore, from one survey to the next. However, for Swansea Bay the ‘long-term’ (i. e. 18 months) range in profile height along that stretch of coast where the alignment of the beach is normal to the direction of wave approach, correlates well with computed wave energy derived from relevant offshore wave directions.
- (b) While beach variability is greatest during the ‘winter’ (i. e. storm) period there is no overall tendency for a drawdown of sediment from the intertidal zone at that time. Response times are relatively short. Thus high beach levels need not necessarily be associated with ‘summer’ conditions.
- (c) Although in Swansea Bay there is a tendency for the beach height to fluctuate least at mid-tide level this is not true of the other two sites. In no area does sediment eroded from the upper exposed part of the beach regularly appear to be deposited on the lower exposed part, or vice versa.
14.
Cristina Celia Martins Michel Michaelovitch de Mahiques João Manuel Alveirinho Dias 《地球表面变化过程与地形》2010,35(4):487-495
This paper examines the daily morphological responses of Sununga Beach, an embayed beach located on the south‐eastern Brazilian coast, to storms in the South Atlantic Ocean. The main mechanisms and timing of beach erosion and accretion, the relationship between wave height and direction, and beach volume changes are considered, to establish a qualitative model for short‐term embayed beach morphological changes. The methodology consisted of daily topographic surveys during the month of May in 2001, 2002, and 2003, using an RTK‐GPS (real‐time kinematics – global positioning system). Weather and wave model results were used to correlate hydrodynamics and beach morphology. The results indicate that the morphodynamics of Sununga Beach are characterized by a process of beach rotation, which occurred more or less clearly during all three surveys. Unlike what has been commonly described in the literature for longer time intervals and alternations of fair and stormy weather, the beach rotation processes on Sununga Beach occurred under conditions of moderate‐to‐high wave energy change (wave heights greater than 2 m). An integrated evaluation of the behaviour of the meteorological aspects, together with beach morphology, enabled us to recognize that extra‐tropical cyclones were the most important agent in remobilizing the beach planform, whether in beach rotation or in cross‐shore erosion. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
15.
Small‐scale variations in surface moisture content were measured on a fine‐grained beach using a Delta‐T Theta probe. The resulting data set was used to examine the implications of small‐scale variability for estimating aeolian transport potential. Surface moisture measurements were collected on a 40 cm × 40 cm grid at 10 cm intervals, providing a total of 25 measurements for each grid data set. A total of 44 grid data sets were obtained from a representative set of beach sub‐environments. Measured moisture contents ranged from about 0% (dry) to 25% (saturated), by weight. The moisture content range within a grid data set was found to vary from less than 1% to almost 15%. The magnitude of within‐grid variability varied consistently with the mean moisture content of the grid sets, following an approximately normal distribution. Both very wet and very dry grid data sets exhibited little internal variability in moisture content, while intermediate moisture contents were associated with higher levels of variability. Thus, at intermediate moisture contents it was apparent that some portions of the beach surface could be dry enough to allow aeolian transport (i.e. moisture content is below the critical threshold), while adjacent portions are too wet for transport to occur. To examine the implications of this finding, cumulative distribution functions were calculated to model the relative proportions of beach surface area expected to be above or below specified threshold moisture levels (4%, 7%, and 14%). It was found that the implicit inclusion of small‐scale variability in surface moisture levels typically resulted in changes of less than 1% in the beach area available for transport, suggesting that this parameter can be ignored at larger spatial scales. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
16.
Beach profile data, collected twice per year at 19 stations over a 25 km length of coastline in Tremadoc Bay, have been analysed to quantify the inter-annual variability in beach levels over a 7 year period and the results compared against the output of a numerical model. Using hourly wind data as forcing, the morphological development of northern Tremadoc Bay was simulated by wave, tidal, longshore transport, total transport and bed level change models. The modelling methodology was efficient and innovative, allowing realistic simulations of long duration with a time step of 1 h, hence capturing the high frequency nature of wind events. The model was run for each of the 7 autumn/winter periods (generally November–April) and the modelled net change in beach levels compared with the data from all 19 stations. The model results had reasonable agreement with the beach profile surveys. However, the observed magnitude of bed level change in the bay lagged the model output by 1 year, indicating that sediment processes acting over a larger area are important in a relatively localised study of inter-annual variability. 相似文献
17.
Determinants of sediment properties and organic matter in beach and dune environments based on boosted regression trees 下载免费PDF全文
下载免费PDF全文 Grain size properties and the variation of organic matter in coastal beach and dune environments are assumed to be controlled by the intensity of aeolian processes, time and the sediment source. However, assumptions are based on relatively limited empirical studies. In this study, we examined which environmental variables are the main predictors of multiple topsoil properties. To achieve this, we analysed an extensive dataset systematically collected across all beach zones and a large geographical area at the Finnish Baltic Sea coast characterized by post‐glacial land uplift. We included a comprehensive set of predictors in the analysis and applied boosted regression trees, a modern modelling technique particularly suited for analysis without prior assumptions of the data model. The results suggest that mean grain size and sorting are mainly determined by northing and fetch. Northing, disturbance and fetch predicted the variation of soil organic matter while litter cover was strongly related to disturbance. Based on the analyses, we were able to identify the main drivers of multiple topsoil properties on land uplift beaches. Parent material is suggested to determine sediment textural properties, which largely masks the effects of transient processes. Mean grain size and sorting are highly interdependent: grains become finer and sorting improves with increasing shore exposure. The intensity of momentary geomorphic processes controls the accumulation of litter whereas the slower accumulation of organic matter in the soil is influenced also by the static exposure setting. Skewness and kurtosis of the grain size distribution are mainly influenced by unmeasured processes, potentially relating to the geomorphological origin of the sediment. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
18.
The drivers (social) and pressures (physical) of marine debris have typically been examined separately. We redress this by using social and beach surveys at nine Tasmanian beaches, across three coastlines and within three categories of urbanisation, to examine whether people acknowledge that their actions contribute to the issue of marine debris, and whether these social drivers are reflected in the amount of marine debris detected on beaches. A large proportion (75%) of survey participants do not litter at beaches; with age, gender, income and residency influencing littering behaviour. Thus, participants recognise that littering at beaches is a problem. This social trend was reflected in the small amounts of debris that were detected. Furthermore, the amount of debris was not statistically influenced by the degree of beach urbanisation, the coastline sampled, or the proximity to beach access points. By linking social and physical aspects of this issue, management outcomes can be improved. 相似文献
19.
Shannon Gore J. Andrew G. Cooper Derek W.T. Jackson Lianna Jarecki 《地球表面变化过程与地形》2019,44(9):1860-1875
Beaches of tropical island coasts exhibit high levels of diversity in composition and form in comparison with their continental counterparts. To investigate the nature and origin of this diversity, individual beach morphology and sedimentology was investigated in the British Virgin Islands (BVI), a Caribbean archipelago of > 60 high volcanic and low reef islands. The islands exhibit a diversity of orientations (some facing the Atlantic and some the Caribbean), elevation and gradient, rock type and wave energy. An examination of 100 beaches in the archipelago revealed a first-order division into sand (70 beaches) and coral rubble (30 beaches). These beaches occur in seven planform types (determined by the antecedent geological framework) and are further subdivided according to shoreface type (seagrass, sandy shoreface, or reef). Mainland-attached headland-embayment beaches are the most common form of sand beach while coral rubble beaches usually occur as barriers that enclose salt ponds and wetlands. Among sand beaches, carbonate content is greatest on Atlantic-facing beaches, and coral rubble beaches are more common on Caribbean-facing beaches. Grain size characteristics on sandy beaches are highly variable and range from fine to very coarse sands while coral rubble beaches range up to boulder-sized clasts. The local source material is a primary determinant of sediment composition. The local factors such as the underlying geology, source and availability of sediments are the primary determinants of beach form, composition and texture in the BVI. Oceanographic and climatic conditions such as the prevailing easterly trade winds and waves which seasonally range in direction from east-northeast to southeast as well as beach orientation to Atlantic- or Caribbean-facing waves also contribute to the variability, but in a secondary role. © 2019 John Wiley & Sons, Ltd. 相似文献
20.
Optically stimulated luminescence dating of a Holocene beach ridge plain in Northern Jutland, Denmark 总被引：1，自引：0，他引：1
Asger Nielsen Andrew S. Murray Morten Pejrup Bo Elberling 《Quaternary Geochronology》2006,1(4):305-312
This study presents results from 20 optically stimulated luminescence (OSL) ages from one of the world's largest beach ridge plains, the Jerup beach ridge plain at the base of the Skagen Spit in the northernmost part of Jutland, Denmark. The OSL ages were obtained using quartz and a SAR protocol, and used to establish a chronology for the beach ridge plain and for the underlying coastal plain. The accuracy of the chronology is tested both by laboratory tests (recuperation, recycling ratio and dose recovery) and by comparison with independent age controls, e.g. previously reported radiocarbon dates, map sources, anecdotal evidence and settlement names. It is concluded that the OSL signals are internally consistent, and that the derived OSL ages are in good agreement with a large range of independent age controls. The ridge plain is shown to cover a time span from 1000 to 2700 years ago; this chronology is more detailed and precise than those previously available, and gives an average beach ridge formation rate of 15 yr/ridge and an average lateral migration rate of 2.0 m/yr. This study adds to the growing knowledge that OSL dating has a large potential for establishing detailed and precise chronologies in coastal marine sediments, including beach ridges. 相似文献