共查询到20条相似文献，搜索用时 31 毫秒
1.
D. M. Ermakov E. A. Sharkov A. P. Chernushich 《Izvestiya Atmospheric and Oceanic Physics》2017,53(9):973-978
This paper is focused on the development of a methodological basis for the authors’ approach to the processing of large volumes of satellite radiothermal data, which is known as satellite radiothermovision. A closed scheme for calculating the latent heat flux (and other integral characteristics of the dynamics of geophysical fields) through arbitrary contours (boundaries) has been constructed and mathematically described. The opportunity for working with static, as well as movable and deformable boundaries of arbitrary shape, has been provided. The computational scheme was tested using the example of calculations of the atmospheric advection of the latent heat from the North Atlantics to the Arctic in 2014. Preliminary analysis of the results showed a high potential of the approach when applying it to the study of a wide range of synoptic and climatically significant atmospheric processes of the Earth. Some areas for the further development of the satellite radiothermovision approach are briefly discussed. It is noted that expanding the analysis of the available satellite data to as much data as possible is of considerable importance. Among the immediate prospects is the analysis of large arrays of data already accumulated and processed in terms of the satellite radiothermovision ideology, which are partially presented and continuously updated on a specialized geoportal. 相似文献
2.
The article presents the results of biogeographic zoning of the epi- and mesopelagic region based on nekton areas using a new modification of the Shorygin method. It is shown that the position and boundaries of biogeographic areas are related to real relatively stable elements of the biotope (water masses, currents, frontal zones, eddies, and rings). A pronounced latitudinal pattern of the areas of natural zones is not always seen. Zoning becomes less detailed from the top layer of the epipelagic to mesopelagic region, and the zonalities of mesopelagic and epipelagic areas are not similar. We propose a new zoning approach to solve dynamic biogeography problems. 相似文献
3.
《Marine Policy》2014
During 2010 a set of 22 voluntary closed areas, distributed around Shetland, were proposed by local industry in order to help protect and conserve threatened habitats from potential physical disturbance from scallop dredging. Initially, closed areas were implemented on a precautionary basis over predicted beds of maerl and horse mussel (Modiolus modiolus) derived from historical data. Horse mussel and maerl beds are classed as priority habitats which have been identified as being threatened and requiring conservation under the UK Biodiversity Action Plan (UK BAP). Legalisation of the voluntarily adopted closed areas occurred in 2011. Detailed surveys were conducted to map each closed area with specific reference to the defining features located within. Closed areas were surveyed using a hull mounted multibeam system and ground-truthed with an underwater camera system. Information was imported to a Geographic Information System (GIS) in order to create georeferenced habitat maps of the two species of interest. The appropriateness of each closed area was assessed and a proposed methodology and procedure outlined for any future closed areas. The primary aim was to provide information on which to test the validity of initial closed area boundaries and subsequently allow managers to refine and add to them in the future. The survey illustrated the need to have good quality acoustic and visual survey work undertaken whenever areas have been closed based on historical data and/or predicted habitats. Predicted beds were not found to be representative of the survey findings. The survey highlighted the lack of good quality, robust, accurate, and up to date species information for the waters around Shetland, especially with regard to priority marine features. Although some were neither fully protecting the UK BAP habitats they were designed to protect nor were protecting any UK BAP habitats, a degree of protection had been conferred to some priority features in the first iteration of implementation of closed areas. Survey data were subsequently used to legally alter the closed area boundaries to more appropriately reflect the distribution of priority features. Recommendations were made on appropriate procedures for defining a species bed and on the wider implications of the study’s findings for other fisheries areas developing spatial management plans. 相似文献
4.
Pau Balaguer Rafael Sard Maurici Ruiz Amy Diedrich Guillermo Vizoso Joaquin Tintor 《Ocean & Coastal Management》2008,51(12):806-814
ICZM relies heavily on the definition of major multidisciplinary characteristics/elements of the coastal area of interest. Usually, only terrestrial boundaries are considered, which tend to respond to a specific sectoral problem and can be determined by administrative limits. In this study, we propose a method for establishing a decision-making tool to inform boundary delimitation for ICZM initiatives that is proactive and widely applicable as opposed to reactive and problem specific. This method integrates environmental, economic and societal characteristics of the marine and terrestrial boundaries of the coastal zone, starting at the boundary of the jurisdictional zone of influence (shoreline units), increasing in detail through the definition of their influential areas from jurisdictional, environmental or socio-economic perspectives (functional areas) and, within them, specifying the finest scale at which relevant indicator data may be obtained (analysis units). 相似文献
5.
《Marine Policy》2017
Spatial boundaries have become an indispensable part of regimes and tools for regulating fisheries, with examples including marine protected areas, regional fisheries management organizations and Exclusive Economic Zones. Yet, it is also widely acknowledged that boundaries are a social construct, which may be resisted by both fishers and fish ecology. The ensuing spatial and institutional mismatches have been shown to frustrate management efforts, exacerbating issues of non-compliance and ultimately leading to conflicts and overfishing. Interestingly, the often static and rigid nature of these boundaries has also led to a concomitant research interest in ‘transboundary’. This paradoxical situation of more boundary-setting entailing more transboundary thinking warrants a deeper understanding about boundaries and the role of transboundary research in fisheries. The aims of this review article are twofold: (1) a theoretical clarification on the meanings and uses of spatial boundaries drawing on geographical “boundary studies” literature; and (2) a construction of a typology that outlines how transboundary research is being articulated and envisioned. Together, the study reveals that transboundary scholarship in fisheries are mostly related to resources, fleets, trade and governance aspects and that dealing with the “boundary paradox” encompasses re-incorporating, re-scaling and re-imagining of boundaries. This article provides a conceptual basis for reflecting upon boundaries in world's fisheries and opens up discussions for a more nuanced boundary application that can better cope with multi-level interactions and dynamicity. 相似文献
6.
鉴于SWAN模型不能有效地模拟侧边界附近的风浪场,详细研究了在不同水深和风速情况下模型侧边界附近波要素,包括波高、周期、波向和波长的变化特征和失真范围。计算结果表明水深和风速的变化对于侧边界附近不同波要素的影响是不同的。在风速一定的情况下,失真范围随着水深的增大而增大。在水深一定的情况下,根据波高、周期和波长的相对误差所计算的失真范围与根据他们的绝对误差所计算的失真范围不同。随着风速的增大,根据相对误差所计算的失真范围减小;而根据绝对误差所计算的失真范围变化不大。随着风速的增大,波向的失真范围减小。研究了在水深变化的水域,包括太湖和淀山湖在内的侧边界附近的风浪场,结果表明如果计算范围不适当扩大确实会导致侧边界附近的风浪场失真。因此在利用SWAN模型模拟计算近岸或内陆湖泊风浪场时,需采取适当的措施以减小计算误差。 相似文献
7.
Forcada A Bayle-Sempere JT Valle C Sánchez-Jerez P 《Marine environmental research》2008,66(5):536-547
Marine protected areas (MPAs) could be useful as fisheries management tools for the exportation of pelagic eggs, larvae and adult fish. A decreasing gradient of fish biomass across MPAs boundary may indicate export. We determine whether gradients of decreasing biomass of fish assemblage occurred in Tabarca Marine Reserve over two habitats with different continuity across the boundaries, to test if the patchy nature of the marine environment might act as a barrier for the fish export. In general, significant decreasing gradients in total fish biomass and biomass of some species were observed on P. oceanica and rocky substrates, independently of their different continuity through the reserve boundaries. Changes in the multivariate structure of the fish assemblage were correlated with the distance from integral reserve. All of these results support the hypothesis that the exportation of adult fish from Tabarca Marine Reserve occurs, and this process may influence the surrounding fished areas. 相似文献
8.
太平洋东边界波浪输运 总被引：4，自引：0，他引：4
通过计算2000年涌浪指标(swell index)的全球分布,发现太平洋东边界赤道附近区域存在涌浪池.利用ECMWF再分析波浪资料,计算出2000年全球月平均波浪体积输运.比较2000年全球月平均波浪体积输运和2000年QUICKSCAT月平均风场,发现在赤道太平洋东边界涌浪池区域内的波浪输运方向和风向存在很大的差别,两者方向相差大约90°.这进一步验证了该地区涌浪池存在的真实性.研究发现,赤道太平洋东边界涌浪主要来源于北太平洋和南太平洋的西风带对应的海区.在涌浪池区域内分别在2.5°S和2.5°N取两条边界(边界起点为125°W,终点为美洲大陆西边界),计算通过这两条边界进入赤道区域涌浪的Stokes体积净输运量.结果表明,不同月份通过南、北两条边界波浪的净输运量与当月南、北太平洋西风带的风浪强度密切相关.同时指出了,涌浪的体积输运将会对大洋环流系统产生潜在的重要影响. 相似文献
9.
A. S. Vasilyev 《Physical Oceanography》1996,7(6):445-454
The paper considers the statement of the problem on quasi-stationary diagnosis of currents, temperature, salinity, and density
fields for multiply connected areas with fluid boundaries. The principles of self-similar parameterization over the vertical
axis are applied by introducing models for the vertical substance distribution, which have two regularly varying functions.
The problem is reduced to handling a set of Poisson equations, enabling the boundary conditions to be automatically determined
at the island shores. A scheme is presented for calculating current velocity components at an arbitrarily oriented transect.
Several examples of current velocity computation for the topographically complex oceanic areas are given which support the
data collectedin situ.
Translated by Vladimir A. Puchkin. 相似文献
10.
《Marine environmental research》2009,67(5):536-547
Marine protected areas (MPAs) could be useful as fisheries management tools for the exportation of pelagic eggs, larvae and adult fish. A decreasing gradient of fish biomass across MPAs boundary may indicate export. We determine whether gradients of decreasing biomass of fish assemblage occurred in Tabarca Marine Reserve over two habitats with different continuity across the boundaries, to test if the patchy nature of the marine environment might act as a barrier for the fish export. In general, significant decreasing gradients in total fish biomass and biomass of some species were observed on P. oceanica and rocky substrates, independently of their different continuity through the reserve boundaries. Changes in the multivariate structure of the fish assemblage were correlated with the distance from integral reserve. All of these results support the hypothesis that the exportation of adult fish from Tabarca Marine Reserve occurs, and this process may influence the surrounding fished areas. 相似文献
11.
《Deep Sea Research Part II: Topical Studies in Oceanography》2009,56(25):2720-2730
Seamount-associated communities and ecosystems have proven to be highly vulnerable to the impact of human activities. Globally, seamount and cold-water coral habitats and species, which often go along with each other, are considered a priority for developing conservation and sustainable management measures within and beyond national jurisdiction. Seamounts may be good candidates for site-based management such as by means of marine protected areas (MPAs), due to their singularity and isolation. In the north-east Atlantic, so far, there are only two seamounts managed as marine protected areas, both in the waters of the Azores, and several others as closed areas to fisheries by Northeast Atlantic Fisheries Commission (NEAFC).This paper describes, using the example of Sedlo Seamount, the development of a framework for the management of activities and interests of a potential offshore marine protected area. The work is based on the scientific results of the OASIS project and on input from various stakeholders, including fishery organizations, government and scientists. It reviews the current state of the site in terms of natural setting, existing uses and potential threats and proposes boundaries and regulations with the overall goal to manage human activities around Sedlo in a way that protects its ecosystem function and biodiversity, and its significance as a rather unexploited example of a seamount within a network of marine protected areas in the NE Atlantic. The resulting proposed management plan is a fundamental prerequisite to the establishment of the Sedlo Seamount as an offshore MPA, contributing to the OSPAR network of MPAs in the north-east Atlantic. 相似文献
12.
1 Introduction A vertical wall is one of the typical maritime sheltering structures in the coastal region, which is mainly subjected to wave forces. It has been a com- mon engineering assumption adopted for design pur- poses that normally incident wave fo… 相似文献
13.
A. I. Shavlyugin 《Izvestiya Atmospheric and Oceanic Physics》2011,47(5):619-627
A quasi-geostrophic contour dynamics model permitting one to study flows induced by a system of vortex patches in a two-layer ocean with round shore boundaries in the presence of specified background flows caused by the bottom relief, the β effect, and sources and sinks at the boundaries is proposed. The principal relations of the model are presented and the algorithm of its numerical realization is described. Some experimental results of the study of the evolution of unstable two-layer vortices are demonstrated. 相似文献
14.
准确计算珊瑚礁的面积是评估其资源、环境效应的基础,但我国迄今对南海珊瑚礁的面积估算仍缺乏共识,缺少可靠的估算方法是导致这一现象的重要原因。针对这一问题,本文以西沙群岛羚羊礁为例,提出了一种利用多时相多光谱遥感影像低成本半自动化估算珊瑚礁面积的方法。首先快速目视确定地貌带分界线的粗略位置,然后利用基于梯度向量场的主动轮廓线模型（Gradient Vector Flow-Snake, GVF-Snake）实现这些分界线位置的自动精化,最后将不同时相的瞬时分界线转换为面要素进行多时相的融合,从而得到珊瑚礁的面积。基于53景Sentinel-2 多光谱成像仪（MSI）影像的实验表明,羚羊礁的总面积为17.22 km2（Landsat 8 陆地成像仪（OLI）用于方法稳定性的验证,得到的羚羊礁面积为17.29 km2）,其中礁前斜坡、礁坪?潟湖坡、潟湖的面积分别为1.76 km2、10.29 km2、5.17 km2。该数值与实测数据具有较好的一致性。具体地,该方法获得的地貌带分界点与实测水深所指示分界点的位置偏差能控制在0.2～4.9 m的范围内（不超过0.5个像素）,珊瑚礁最外轮廓线与30 m等深线的位置偏差亦在1个像素大小内（5.7～9.5 m）,而估算面积与高分辨率WorldView-2影像解译得到的面积差异为0.02%。同时,该方法获得的珊瑚礁边界线的完整度、正确度、提取质量精度能够由单时相平均的60%、64%和54%分别提高至84%、83%和72%。此外,该方法能够减小基于不同遥感数据源的珊瑚礁面积估算结果的差异,即6景以上的多时相Sentinel-2 MSI和Landsat 8 OLI影像提取的珊瑚礁面积标准差分别不超过0.01 km2和0.05 km2,仅相当于珊瑚礁总面积的0.2%和0.5%。总而言之,该方法能够用低成本的10 m分辨率Sentinel-2 MSI和30 m分辨率Landsat 8 OLI影像获得接近1.8 m分辨率WorldView-2影像的面积估算精度,且具有良好的稳定性和可靠性。 相似文献
15.
Graham J.M. Copeland 《Coastal Engineering》1985,9(2):125-149
The “mild-slope” equation which describes wave propagation in shoaling water is normally expressed in an elliptic form. The resulting computational effort involved in the solution of the boundary value problem renders the method suitable only for small sea areas. The parabolic approximation to this equation considerably reduces the computation involved but must omit the reflected wave. Hence this method is not suited to the modelling of harbour systems or areas near to sea walls where reflections are considerable. This paper expresses the “mild-slope” equation in the form of a pair of first-order equations, which constitute a hyperbolic system, without the loss of the reflected wave. A finite-difference numerical scheme is described for the efficient solution of the equations which includes boundaries of arbitrary reflecting power. 相似文献
16.
Abstract The use of marine high‐resolution geophysical profiling data, seafloor soil samples, and accepted land‐based methods of analysis have provided a means of assessing the regional geotechnical conditions and relative slope stability of the portion of the Gulf of Alaska Continental Margin known as the Kodiak Shelf. Eight distinct types of soils were recognized in the study; the seafloor distribution of these indicates a complex geotechnical setting. Each soil unit was interpreted as having a distinct suite of geotechnical properties and potential foundation engineering problems. Seven categories of relative slope stability were defined and mapped. These categories range from “highest stability”; to “lowest stability,”; and are based on the degree of slope of the seafloor, type of soil underlying the slope, and evidence of mass movement. The results of the analysis indicate that the highest potential for soil failure exists on (1) the slopes forming boundaries between the submarine banks and the broad sea valleys, and (2) the upper portion of the continental slope, where evidence of past slope failure is common. Also of concern are gently sloping areas near the edges of submarine banks where evidence of possible tension cracks and slow downhill creep was found. 相似文献
17.
The fundamental principle for differentiating water masses is a strict consideration of their relative "interior homogeneity" and obvious "exterior differences" with others in characteristics. The conceptions of water type, water mass and water system are dealt with on the basis of the theory of fuzzy sets. A proposal to apply the theory of fuzzy sets to define the water mass and its core, independent area, boundary and mixing area is put forward.As an example, the membership function of the surface water masses in the Yellow Sea and East China Sea in August, 1979, are considered. Their cores, independent areas, boundaries, mixing areas and the approximation degrees between different water masses are calculated respectively. The water masses are ranged according to their fuzzy degrees. 相似文献
18.
《Marine Policy》2013
Proponents of catch share-based fisheries have claimed ecological stewardship can result from the assignment of individual catch quotas. This claim is examined by analyzing the distribution of benthic habitat protection measures adopted by quota-owning industry sectors within the exclusive economic zones (EEZs) of the U.S. (Alaska), New Zealand, and high seas seamounts within the Southern Indian Ocean Deepsea Fishers Association (SIODFA) competence area. Results suggest the protection of both benthic ecosystems and essential fish habitat (EFH) are marginal at best when quota owners have primacy in determining the boundaries of bottom trawl closures. The majority of the areas in these three regions that are closed to trawling are too deep to fish, may not contain vulnerable marine ecosystems, and do not have high abundances of commercially important species. “Freezing the footprint” of bottom trawling is not the best method for benthic habitat protection in areas where the fishing industry is actively fishing vulnerable habitats. Analytical methods should be applied to help determine boundaries of future bottom trawl closures rather than allowing the fishing industry to place benthic protection areas (BPAs) in areas where they are not interested in fishing. 相似文献
19.
《Marine Policy》2014
In any given region, there are multiple options for terrestrial protected area networks that achieve goals for conservation of terrestrial biodiversity and ecosystem values. When deciding on the location of terrestrial protected areas, planners typically focus only on terrestrial conservation goals, ignoring potential linked benefits to marine ecosystems. These benefits include maintenance of downstream water quality, as forest protection can prevent changes in amount and composition of river runoff that negatively impacts coral reefs. This study aims to determine the benefit of different terrestrial reserve networks to the condition of coral reefs adjacent to the main islands of Fiji to support the work of Fiji's Protected Area Committee in expanding the national protected area estate through integrated land–sea planning. Options for terrestrial protected area networks were designed using six approaches, where the primary objective of each approach was to either achieve terrestrial conservation goals (e.g., represent 40% of each vegetation type) or maximize benefits to coral reefs by minimizing potential for land-based runoff. When achieving terrestrial conservation goals was the primary objective, the potential benefits to coral reef condition were 7.7–10.4% greater than benefits from the existing network of protected areas. When benefiting reefs was the primary objective, benefits to coral reefs were 1.1–2.8 times greater per unit area than networks designed to only achieve terrestrial conservation goals, but 31–44% of the terrestrial conservation goals were not achieved. These results are already being used by Fiji's Protected Area Committee to modify the boundaries of existing priority places to deliver outcomes that better meet terrestrial conservation goals while offering greater benefits to coral reef condition through prevention of run-off. 相似文献
20.
用模糊集合观点讨论水团的有关概念 总被引：1，自引：0，他引：1
本文将划分水团的基本原则,概括为水团内部特征的相对均一性及其与外部海水的明显差异性。用模糊集合讨论了水型、水团和水系等有关概念。提出了用模糊集合观点定义水团及其核心、本体、边界与混合区的建议,并以1979年8月黄海和东海表层为例,给出了各水团的隶属函数。计算了其核心、本体、边界、混合区及贴近度,按其模糊性排出了顺序。 相似文献