共查询到20条相似文献，搜索用时 359 毫秒
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为探讨港口投资的最大效益，利用遗传算法来解决港区堤防布置的优化问题。针对问题的特性设计了目标函数、编码方式和适应度计算，选用了适当的选择、交叉和变异操作，数据结果显示该方法具有良好的搜索性能。 相似文献
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由于来自江河的淡水在多数情况下携带大量的营养盐入海，河口海区成为适合于特殊门类的有机物生长的有利海洋环境。与此同时，大量的人类与工业废弃物也随着江河径流入海，从而严重地影响到河口海区的生态环境。鉴于上述原因，淡水入流的生态学 意义现正被广泛地研究。 相似文献
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中国水环境腐蚀试验站网工作回顾与展望 总被引：6，自引：0，他引：6
材料在天然水环境(海洋、江河、湖泊)中的腐蚀造成了巨大的经济损失。一般来说，发达国家因材料腐蚀造成的损失占其GDP的2％-4％，而材料在水环境中的腐蚀损失大于总腐蚀损失的1／3。因此，材料在水环境的腐蚀数据积累及试验研究一直受到各国的重视。由于材料的自然水环境腐蚀十分复杂，影响因素很多，难以在实验室进行模拟，必须通过野外试验站点现场暴露试验和观测，才能获得符合实际的腐蚀数据和规律。自上世纪初开始，工业发达国家就通过建立水环境腐蚀试验暴露装置和站点， 相似文献
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1992年，联合国自然与环境组织对世界各地的江河入海口进行了一次考察。当他们来到我国海南万泉河口时，顿时被它的美丽姿容惊呆了，那清而又清的河水，绿而又绿的河岸，竟然没有一丝污染，一丝人工之力，一切都保持着原始、自然的美。经全面考察评定，万泉河口的自然景观和天然生念环境之佳位于世界榜首。于是联合国公布中国万泉河口为世界最佳的江河入海口。 相似文献
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Argos系统在我国海洋水文气象自动观测中的应用(一) 总被引：2，自引：1，他引：2
前言 Argos是法国和美国联合建立的一个数据收集和定位系统。它面向全世界,供测量和研究陆地、水域(江河、湖泊和海洋)以及大气圈的物理、化学及生物特性之用。它利用两颗极轨卫星传送各种环境监测数据,并对测量仪器的运载体进行定位。我国从1985年11月起开始使用Argos系统传送海洋水文气象观测数据和定位,至今已有5个项目使用了或者购置了设备准备使用Argos系统。要使Atgos系统这样的外国先进技术手段真正为我 相似文献
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黄河入海流路自1976年5月改道至清水沟流路以来,其地貌形态一直处于剧烈的变化当中,以往的研究虽然关注了典型断面主槽的形态特征及过流能力的变化,但对于清水沟流路范围界限内河道断面整体形态及其沿程变化等地貌特征还缺乏系统研究.本文以2019年10月黄河口现行清水沟流路范围渔洼以下河段加测横断面为研究对象,辨识现状地貌分布特点和横断面沿程形态特征,并分析其成因.结果表明:黄河口地貌形成受自然演变和人类活动的影响,既具有主槽、滩地、堤防等河流地貌要素,又具有滩涂、潮沟、拦门沙等海洋地貌要素.在有堤防河段,主槽形态窄深,过流能力较强;在无堤防河段,主槽形态宽浅,过流能力较差;从滩槽高差、唇滩高差、滩地横比降三个指标来看,无堤防河段的"自然悬河"程度大于有堤防河段的"二级悬河"程度.黄河口悬河程度小于黄河下游大部分河段,但黄河口尾闾河道的滩地横比降依然远大于河道纵比降,若发生漫滩洪水将极易引起顺堤行洪,会对黄河口堤防安全造成极大威胁. 相似文献
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The analysis of the structure of the cryolithozone, facies, and thicknesses of the Quaternary sediments and the results of the physicochemical mathematical modeling of the modern shelf of the western part of the Laptev Sea support the influence of the Late Pleistocene glaciations on the heat conditions and the distribution of the permafrost in the area. A ～200-m thick glacier formed under aerial conditions from atmospheric precipitation represented the metamorphosed snow cover. According to the modeling, the long-living (from 60?50 to 10?4 ky) glacier reduced the thickness of the permafrost rocks in the reviewed shelf area for 280–360 m. The Holocene marine transgression additionally decreased the thickness from 50–140 m on the inner shelf to 220–350 m on the outer shelf. The modern submarine cryolithozone 450-0 m thick is wide-spread in the studied region from the coast to the shelf boundary (isobaths of 130–140 m), where it pinches out at a distance of ～380 km from the coast at a depth of ～250 m above the sea level. 相似文献
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We analyze the components of the carbon system of the Sevastopol bay waters and the balance of main sediment-forming substances
using the data of field investigations in 1998–2008. The interannual variations of total inorganic carbon and the equilibrium
partial pressure of carbon dioxide in the bay water are noted. An increase in the flux of carbon dioxide into the bay and
in the content of organic carbon in bottom sediments is revealed, and an explanation of this phenomenon is given. The priority
accumulation of organic carbon in the sediments of the bay is established. We assess the interannual variation in the relative
abundances of organic and inorganic carbon as an index of the carbon cycle stability. 相似文献
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We generalize and analyze the state of investigations of the influence of river waters on the hydrologic structure of the
Black Sea. Specific features of the water, regime and hydrography of rivers flowing into the sea, data on the discharge of
rivers, and intrayear and interyear variability of the discharge are presented. We discuss and analyze works studying the
transformation of river waters, routes of desalinized sea waters, and their influence on the thermohaline structure and dynamic
regime of the sea.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
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V. A. Ivanov S. P. Lyubartseva N. Mikhailova N. B. Shapiro 《Physical Oceanography》2001,11(6):509-524
We analyze the results of numerical calculations performed according to the three-dimensional interdisciplinary model of an
ecological system of the Black-Sea shelf zone near the estuary of the Danube. The complete system of equations of hydrothermodynamics
is solved together with transport equations of the advection-diffusion-reaction type used to describe the transformation of
a substance (nitrogen) between the components of the characteristic vectors of the ecosystem: plankton, detritus, and biogenic
elements (nitrates). We describe the distinctive features of the circumcontinental distribution of components obtained as
a result of numerical experiments and present arguments for the conclusion that the ecosystem of the Danube estuary water
area plays the role of a buffer zone between the press of the Danubian biogenic pollutions and the neighbouring areas of the
shelf zone and open sea.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
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Ten years of semistationary studies of the interaction of the ice cover and the coastal relief of the Kandalakhsa Gulf in the White Sea allowed us to reveal the peculiarities of these processes in the warm and cold years and the mechanisms of the origination of ice forms, including ice tents, which govern the character of the tidal flats. Three dynamic fast ice zones are distinguished by their geomorphological location, morphology, and ice dynamics. The dependence of the mechanisms and volumes of the enrichment of the fast ice in the sediments on the coastal zone??s relief was established. At the coast of the Kindo Peninsula (Velikaya Salma Strait), the ice mostly contains fine-sandy sediments. Coarser sediments, including boulders, are occasional and frozen into the ice at the contact of the fast ice and the bottom. At the expense of the ice??s spreading by 4?C6 times in the warm years and 2?C4 times in the cold years, several thousand tons of sediments mostly from the tidal flat??s surface (100?C700 m3 from 1 km of coast in the wide tidal flats and <50 m3 on the steep coasts) are delivered to the water area. 相似文献
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Relationship between the path of the Kuroshio in the south of Japan and the path of the Kuroshio Extension in the east 总被引：2，自引：0，他引：2
A relationship between paths of the Kuroshio and Kuroshio Extension (KE) is investigated, using the satellite-derived altimetry
dataset of 1993–2008. When the Kuroshio takes the nearshore nonlarge meander path or typical large meander path and resultantly
goes through the deeper channel (about 2500 m) of the Izu-Ogasawara Ridge, the KE path adopts a relatively stable state with
the two quasi-stationary meanders. On the other hand, when the Kuroshio takes the offshore nonlarge meander path and then
passes over the shallower part of the Ridge (about 1000 m), the KE path tends to be convoluted, i.e., an unstable state. 相似文献
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Izvestiya, Atmospheric and Oceanic Physics - Analysis of the temporal variations of the virtual heights of the sporadic E layer (h?ES) determined from ionograms with increased accuracy (1... 相似文献
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I. E. Timchenko A. A. Primalenny V. D. Yarin E. F. Vasechkina E. M. Igumnova 《Physical Oceanography》2001,11(4):367-378
We use many-year archival observations of hydrologic and hydrobiologic state of the Sea of Azov for the identification of
the structure of a model of its ecosystem. The ecosystem model, supplemented with expert estimates of bioresource consumption
(fish reserve), contamination level, and possible ecologic fines for violation of the sea natural state, is formalized by
the method of system dynamics. Hereat, the major part of influence functions is found in terms of observational data with
application of self-organization algorithms. We also present the results of simulated experiments with the model of the ecosystem,
which enable us to analyse scenarios of its behaviour under the influence of various external factors (wind, river discharge,
water exchange with the Black Sea, etc.).
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
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The methodology and the first results of the computations of the volumes, masses, and growth rates of the sedimentary body of the buried Black Sea basin are presented. Their temporal evolution reflects the regional paleogeodynamics, in particular, the reorientation of the vector of the relative movement of the Arabian and Eurasian lithospheric plates and the related intensification of their collision in the late Miocene-Pliocene. 相似文献
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E. L. Vinogradova 《Oceanology》2008,48(4):483-492
The spatiotemporal variability of the hydrochemical composition of the riverine runoff in nearmouth areas is presented using the example of selected rivers of the Arctic Basin. The temporal dynamics of the riverine nutrient runoff are mainly determined by the seasonal and interseasonal variations in the drainage basins. The spatial variations in the chemical composition of riverine waters in the near-mouth areas are mainly caused by the dynamics of the water flow and the river bed relief and, to a lesser degree, by biochemical processes. It is shown that the variations in the nutrient composition of the waters in near-mouth areas are comparable in magnitude to those at the river-sea geochemical barriers. 相似文献