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以QSCAT/NCEP混合风资料和Myers经验模型风场构造台风风场,并以之作为驱动风场,建立一个基于第三代海浪模式SWAN的两重嵌套台风浪数值模拟模型。以0601号台风珍珠为例,对南中国海至广东的台风浪进行数值模拟研究。将数值模拟结果与台风期间Jason-1卫星高度计观测资料和近岸浮标实测资料(波高、波向和波周期)作了较为详细地比较,并分析台风浪要素的时空分布。结果显示台风浪要素的数值模拟值与实测值吻合良好,表明SWAN模型能够较好地再现大洋和近岸台风浪的时间发展过程和空间分布特征。 相似文献
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根据24年CCMP风场资料和江苏沿海4个方向(N、NE、E和SE)百年一遇风速,构建西北太平洋、东中国海和江苏沿海上述4个方向的百年一遇风场。首次建立一个基于第三代海浪模型SWAN的自西北太平洋、东中国海至江苏沿海的三重嵌套数值模型,以AVISO卫星观测数据和江苏沿海定点实测数据进行验证。以三个计算域4个方向百年一遇风场为驱动风场,驱动该多重嵌套模型,高精度数值模拟江苏沿海4个方向百年一遇有效波高分布并进行分析。结果表明,江苏沿海辐射沙洲地形对有效波高分布影响显著;E向百年一遇风场作用下海域有效波高最大,NE向次之,N向和SE较小。 相似文献
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应用广义Pareto分布(GPD)分析超阈值波高序列的设计值。以位于美国北卡罗来纳州的FRF历时32年连续测量的逐日波高序列为例,检验了不同波高阈值样本的泊松分布,采用多种方法综合确定最佳阈值的拟合优度指标。对最优广义Pareto分布和GEV分布及P-Ⅲ分布推算的波高重现水平做了对比分析。得到以下结论:(1)波高的GPD属于短尾型分布;(2)拟合优度指标表明构建的波高GPD模型普遍优于GEV和P-Ⅲ型;(3)GPD的参数估计方法对设计波高的计算结果有较大影响。 相似文献
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台风浪模拟预报中的风场比较研究 总被引：1，自引：0，他引：1
在对模拟台风浪时海浪模式常用的经验模型风场和多重嵌套中尺度气象数值模式风场的结构和时间演变特征进行对比分析的基础上,分别采用这两种风场资料,应用最新版本的第三代海浪模式SWAN对Winnie(1997)引起的台风浪进行了模拟,将模拟的有效波高与TOPEX/POSEIDON和ERS-2卫星高度计资料作了详细的对比分析。结果表明,经验模型风场对实际台风风场的刻画存在诸多缺陷,这些缺陷对于台风浪的准确模拟产生了不可忽视的影响,采用模式风场试验的模拟效果优于采用模型风场的试验。论文提出了在运用海浪模式模拟台风浪时用数值模式模拟风场替代经验模型风场的必要性。 相似文献
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简要论述了当前广泛使用的极值理论和极值分布理论3个概率分布模型——标准耿贝尔(SG)分布、广义极值(GEV)分布和广义帕累托分布(GPD).应用模型推算广东沿海9个站点的极值风速,对比分析结果表明:(1)3个模型都是推算极值风速的合适模型,但GPD模型可更充分地利用实际观测站点数据,风速拟合的PPCC和RMSE指标确定GPD是更优的概率模型; (2)选取的超阚值风速样本服从GPD-Ⅱ型分布,偏向于给出比SG模型和GEV模型更大的极值风速估计值; (3)从工程安全考虑,尤其在观测数据较少情况下推算工程设计风速可优先选用GPD模型. 相似文献
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基于加密的非结构三角网格,以Holland模型风场叠加美国国家环境预报中心(NCEP)海面风场构造的合成风场驱动第三代浅水波浪数值模型(SWAN)对2017年影响闽东海域的"纳沙"和"泰利"台风过程进行数值模拟,并运用浮标站的实测数据对模拟结果进行验证.结果表明,模型计算的风速、有效波高与实测值符合较好,合成风场能较好地模拟台风期间的风速变化过程,SWAN模式能够合理地再现闽东沿海台风浪的时空分布特征.由模拟结果可见:台风"纳沙"中心越过台湾岛进入台湾海峡北部海面,受海峡地形的约束,其波浪场呈NE—SW向椭圆状分布,北部海域的浪高大于南部,闽东沿海遍布大范围的巨浪到狂浪;超强台风"泰利"未登陆闽东,当其台风中心与大陆的距离最近时,海面波浪场分布与台风风场结构一致,台风中心附近海域为14 m以上的怒涛区,巨浪遍布于闽东沿海.研究结果可为闽东沿海台风浪灾害预警和应急管理提供技术支撑和参考依据. 相似文献
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获取高分辨率的风场数据和气压场数据是精确模拟台风浪的基础,采用经验公式构建台风风场和气压场对海浪模式进行驱动,无法反映台风影响下海气动力过程,难以提供高精度的风场、气压场数据。本文基于中尺度大气模式WRF(Weather Research and Forecasting model)和第三代海浪模式SWAN(Simulating WAves Nearshore model),构建了南中国海地区大气—海浪实时双向耦合模式,针对超强台风"威马逊"进行数值模拟。将数值模拟结果与现场观测结果及卫星高度计观测结果进行对比验证,验证结果表明,本文建立的WRF-SWAN耦合模式在对台风"威马逊"影响下的南中国海台风浪的模拟中展现出较高的模拟精度,揭示了台风风场分布和台风浪分布在空间上的"右偏性"不对称分布特征及其形成机制。基于WRF和SWAN建立的大气-海浪实时双向耦合模式能够准确模拟台风动力过程以及台风浪的时空分布特征,可以推广用于南中国海地区台风浪的模拟分析。 相似文献
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2011年6月-8月渤海湾溢油事故长期后报数值模拟 总被引：1，自引：1，他引：0
三维业务化溢油应急预报系统不仅能提供逐时的海洋环境信息预报和溢油漂移扩散,还能对溢油事件进行后报数值模拟。2011年6月4日在渤海湾蓬莱19-3B采油平台发生溢油事件,同月17日19-3C平台也发生溢油事件。此次溢油事故造成了数千平方公里海水受污染。本文采用国家海洋环境预报中心自主研发的溢油模型对蓬莱19-3溢油事件进行长期后报数值模拟,在风流海洋环境场的驱动下,模拟了2016年6月到2016年8月,两个平台溢油的漂移扩散情况、影响范围,靠岸时间和影响岸段等。风场采用基于WRF模型模拟得到的再分析风场,并用实测风对再分析风场进行订正,流场采用基于POM模式在再分析风场驱动下得到的海流。后报结果显示,溢油主要向西北方向漂移,并最终靠岸,其扫过的海域也主要在平台的西北方向,这与观测结果一致,验证了后报的可靠性。 相似文献
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海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。 相似文献
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Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans 总被引：1，自引：0，他引：1
A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level. 相似文献
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Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges. 相似文献
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A vertically integrated model has been used to study the tidal circulation and currents in the Gulf of Kachchh along the west coast of India. The model is fully nonlinear and uses a semiexplicit finite difference scheme to solve the basic hydrodynamic equations on a staggered grid. The model is forced by prescribing the tides along the open boundary of the model domain. The flow is simulated both with and without the presence of the proposed tidal barrage across the Hansthal Creek in the Gulf of Kachchh. The results show a considerable change in the behavior of the tidal flow in the presence of the barrage. 相似文献
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利用中国GF-3卫星SAR和HY-2A卫星微波散射计的首次台风联合定量观测 总被引：4，自引：0，他引：4
<正>The typhoon,as a mature tropical cyclone that develops in the western part of the North Pacific Ocean with high wind speed and heavy rainfall,is one of the most lethal and costly of natural disasters for the densely populated countries of East Asia.It can be easily detected by space-borne sensors operated at microwave,visible or infrared bands(Liu et al.,2014).Synthetic Aperture Radar(SAR)is 相似文献
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Soil core samples fromRhizophora mangleL. andAvicennia schauerianaStapf & Leech forests from south-eastern Brazil were analysed for their total organic matter content and their sugars, amino acid and amino sugars composition. Organic carbon and nitrogen contents were higher inAvicenniathan inRhizophorasoils. The contribution of sugars and amino acids to the total organic carbon pool was constant with depth inRhizophorasoils whereas inAvicenniasoils it increased. Spectral distribution of sugars and amino acids showed a dominance of Ca-affine monomers, particularly acidic amino acids, and the sugar arabinose. Biogeochemical indicators derived from ratios of individual sugar and amino acid monomers confirm previous studies which showed that organic matter in both soils is mainly of mangrove origin. The results further suggest accumulation of organic matter inRhizophorasoils and a continuing degradation of organic matter inAvicenniasoils. The latter may thus release more nutrients to adjacent ecosystems thanRhizophorasoils. 相似文献
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《African Journal of Marine Science》2013,35(1):181-203
Orange roughy Hoplostethus atlanticus are unusual fish. They form dense aggregations that have fuelled lucrative fisheries at great depths (600–1 400 m), especially off Namibia, New Zealand and Australia. They are thought to be very long-lived (>100 years, maturity at 22 – 40 years), and to have exceptionally low natural mortality (M = 0.045–0.064 year?1) and slow growth rates (K = 0.055–0.070 year?1). In addition, they spawn large eggs and have low fecundity. These factors combine to make orange roughy highly susceptible to overfishing; most stocks are below 30% of pristine levels. Assessments are obtained from indices of catch rate and trawl, acoustic and egg surveys. Acoustic estimates are the most direct, but are confounded by the species' low target strength (?50 to ?53 dB)–attributable to the wax-filled swim bladder. Extracellular wax esters are stored in abundance and comprise mostly mono-unsaturated fatty acids, with low concentrations of the ω-3 fatty acid family. This unusual composition (resultant from the species' diet) ensures neutral buoyancy. Stock separation has been inferred mainly from biological studies, but genetic studies have also found differences among stocks within New Zealand and Australia. Deep-water habitat may be damaged by trawling operations and may take many years to recover, so in some quarters there is a call for a portion of suitable habitat to be set aside for preservation. Although Namibian orange roughy are shallower, smaller and younger than those in other stocks, the Namibian fishery sustained high catches for only a few years before quotas were reduced, from 12 000 to 1 875 tons. Three management lessons are suggested for developing orange roughy fisheries based on the Namibian experience: (1) imposition of catch limits during exploratory fishing; (2) starting the acoustic surveys earlier in the fishery, if possible; (3) greater reliance on trends in catch rate until a survey series has been established. 相似文献