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Information systems developed for different applications within the environmental domain have common characteristics, which can potentially be abstracted for sharing and reuse of design and software modules. This article presents an approach to designing for reuse by abstracting commonalities in the design of a Marine Information System (MIS), facilitating data management in a prototype operational monitoring, forecasting, and management system for the North Atlantic and the Nordic Seas. A detailed study of the requirements and data analysis was carried out, and Object-Oriented Technology (OOT) is employed to encapsulate abstractions and to promote reuse of code and design. This article identifies the Object-Oriented Frameworks (OOFW) required to build the MIS. It also provides guidelines to environmental scientists for restructuring legacy software and employing modern programming techniques. 相似文献
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This paper is part of a comprehensive review of the oceanography of the eastern tropical Pacific, the oceanic region centered on the eastern Pacific warm pool, but also including the equatorial cold tongue and equatorial current system, and summarizes what is known about oceanographic influences on seabirds and cetaceans there. The eastern tropical Pacific supports on the order of 50 species of seabirds and 30 species of cetaceans as regular residents; these include four endemic species, the world’s largest populations for several others, three endemic sub-species, and a multi-species community that is relatively unique to this ecosystem. Three of the meso-scale physical features of the region are particularly significant to seabirds and cetaceans: the Costa Rica Dome for blue whales and short-beaked common dolphins, the Equatorial Front for planktivorous seabirds, and the countercurrent thermocline ridge for flocking seabirds that associate with mixed-species schools of spotted and spinner dolphins and yellowfin tuna. A few qualitative studies of meso- to macro-scale distribution patterns have indicated that some seabirds and cetaceans have species-specific preferences for surface currents. More common are associations with distinct water masses; these relationships have been quantified for a number of species using several different analytical methods. The mechanisms underlying tropical species–habitat relationships are not well understood, in contrast to a number of higher-latitude systems. This may be due to the fact that physical variables have been used as proxies for prey abundance and distribution in species–habitat research in the eastern tropical Pacific.Though seasonal and interannual patterns tend to be complex, species–habitat relationships appear to remain relatively stable over time, and distribution patterns co-vary with patterns of preferred habitat for a number of species. The interactions between seasonal and interannual variation in oceanographic conditions with seasonal patterns in the biology of seabirds and cetaceans may account for some of the complexity in species–habitat relationship patterns.Little work has been done to investigate effects of El Niño-Southern Oscillation cycles on cetaceans, and results of the few studies focusing on oceanic seabirds are complex and not easy to interpret. Although much has been made of the detrimental effects of El Niño events on apex predators, more research is needed to understand the magnitude, and even direction, of these effects on seabirds and cetaceans in space and time. 相似文献
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针对白沙河地下水含水层的内部结构和本区开采特点以及已出现的环境问题,建立了地下水资源管理模型,确定了优化开采方案。该管理模型针对本区每年2个管理时段的长度及其开采量均不同的特点,导出了新的响应矩阵的公式。管理模型的建立有助于对该区地下水的合理开采。 相似文献
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The influence of cyclic loading on the strength and deformation behavior of cemented marine clay has been studied. This marine clay is of recent Pleistocene origin and deposited in a shallow water marine environment. Open pits were dug in sheeted enclosures and from these pits, undisturbed samples were taken for strength testing. A series of standard triaxial shear tests and stress controlled one-way cyclic load tests were conducted at consolidation stress ranges below and above the preconsolidation pressure. For the stress levels below the preconsolidation pressure, the cyclic loading has brought about the collapse of the cementation bond through an increase in strains, and at higher pressure ranges, the soil behaves like typical soft clay. This experiment studied the rate of development of strain and pore water pressure and shows that rate is a function of number of cycles, applied stress, and stress history. In addition, soil degradation during cyclic loading is studied in terms of Degradation Index. Attempt has been made to predict stain, pore water pressure, and degradation index through an empirical model. 相似文献
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菊花岛周围海域38个站表层沉积物的铁、锰、铝、钛、磷、有机质、氮、铜、锌、铅、镉、镍和汞等化学要素含量的Q型因子分析计算表明,本区可划分为三个化学元素沉积区:1.海流悬浮沉积区;2.近岸波浪作用区;3.波浪海流作用区。柱状沉积物中铁等化学元素的迁移、富集受氧化——还原界面的控制。 相似文献
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在室内水池中观察了黑鲷(Sparusmacrocephalus)和青石斑鱼(Epinephelusawoara)对孔径0.5mm、孔距5.0cm,空气压力0.25kg/cm2固定气泡幕的反应。结果表明,气泡幕对两种海水鱼都有显著的阻拦作用,平均阻拦率分别为黑鲷75.1%、青石斑鱼82.4%。分析显示,气泡幕对两种鱼的阻拦率间无显著差异。在本实验中,该两种鱼对气泡幕均无明显的适应现象 相似文献