排序方式: 共有40条查询结果,搜索用时 15 毫秒
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非线性波浪时域计算的三维耦合模型 总被引:3,自引:1,他引:2
将计算区域Ω划分为内域Ω1和外域Ω2(Ω2=Ω-Ω1),外域控制方程采用改进线性频散特性的二维Boussinesq方程,用预报一校正法数值求解;结构物附近的内域控制方程为三维Navier-Stokes方程,由VOF方法数值求解。通过在外域和内域相匹配的交界面上设置合适的速度和波面边界条件,建立了三维非线性波浪时域计算的耦合模型。模拟试验表明:(1)耦合模型数值波浪水池可以产生稳定的、重复性较好的波动过程;(2)用耦合模型数值波浪水池求解较大浅水区域上的非线性波浪数值计算问题可以取得较高的计算效率,同时又能得出结构物附近的复杂流场。 相似文献
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东亚季风区风场异常主要经验模态及其与ENSO的联系 总被引:1,自引:0,他引:1
应用矢量经验正交函数方法、利用1958年1月至2001年12月850 hPa月平均风场(5°~40°N,100°~160°E)范围网格点资料对东亚季风区异常季风场进行分析.结果表明,异常季风典型流场第一模态(VEOF-1)属于ENSO相关模态,其时间模态与ENSO之间具有高的正相关关系,但以季风异常滞后ENSO进程7~8个月为最显著.这表明,东亚热带和副热带季风风场变异规律与ENSO活动有紧密联系.提出了一个VEOF-1与ENSO之间相互作用的概念模型. 相似文献
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Vertical structure and evolution of the Luzon Warm Eddy 总被引:4,自引:0,他引:4
Eddies are frequently observed in the northeastern South China Sea (SCS). However, there have been few studies on vertical
structure and temporal-spatial evolution of these eddies. We analyzed the seasonal Luzon Warm Eddy (LWE) based on Argo float
data and the merged data products of satellite altimeters of Topex/Poseidon, Jason-1 and European Research Satellites. The
analysis shows that the LWE extends vertically to more than 500 m water depth, with a higher temperature anomaly of 5°C and
lower salinity anomaly of 0.5 near the thermocline. The current speeds of the LWE are stronger in its uppermost 200 m, with
a maximum speed of 0.6 m/s. Sometimes the LWE incorporates mixed waters from the Kuroshio Current and the SCS, and thus has
higher thermohaline characteristics than local marine waters. Time series of eddy kinematic parameters show that the radii
and shape of the LWE vary during propagation, and its eddy kinetic energy follows a normal distribution. In addition, we used
the empirical orthogonal function (EOF) here to analyze seasonal characteristics of the LWE. The results suggest that the
LWE generally forms in July, intensifies in August and September, separates from the coast of Luzon in October and propagates
westward, and weakens in December and disappears in February. The LWE’s westward migration is approximately along 19°N latitude
from northwest of Luzon to southeast of Hainan, with a mean speed of 6.6 cm/s. 相似文献
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To discuss the intrusion of the Kuroshio into the SCS, we examined the mixing between the North Pacific and South China Sea (SCS) waters based on in-situ CTD data collected in August and September 2008 and the moored ADCP data taken from mid September 2008 to early July 2009. The CTD survey included four meridional sections from 119°E to 122°E around the Luzon Strait, during which pressure, temperature, and salinity were measured. The CTD data show that the isopycnal surface tilted from the SCS to the North Pacific; and it was steeper in the lower layers than in the upper ones. Meanwhile, we found strong vertical mixing taken place in the areas near 121°E. The Kuroshio in high temperature and salinity intruded westward through Luzon Strait. The frequency of buoyancy was one order of magnitude greater than that of the common ones in the ocean, suggesting stronger stratification in the northeastern SCS. On the other hand, the long-term ADCP data show that before late October 2008, the direction of water flow in the SCS was eastward, and from November 2008 to late February 2009, it turned northwestward in the layers shallower than 150 m, while remained unchanged in deep layers from 200 to 450 m. From March to June 2009, the direction shifted with increasing depth from northward to southward, akin to the Ekman spiral. EOF analysis of the current time series revealed dominant empirical modes: the first mode corresponded to the mean current and showed that the Kuroshio intrusion occurred in the upper layers only from late December to early March. The temporal coefficient of the first and the second mode indicated clearly a dominant signal in a quasi-seasonal cycle. 相似文献
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耦合湿地模块的流域水文模型是开展流域湿地变化的水文效应及其水文功能评估的有效工具,其模拟效率直接关系到模拟精度和应用价值。选取中国湿地主要分布区之一的嫩江流域,利用PHYSITEL/HYDROTEL模型平台,构建孤立湿地和河滨湿地模块并与流域水文模型耦合,并从拟合优度指数和模拟效率角度评价了耦合湿地模块的流域水文模型模拟效率。结果表明,耦合湿地模块的流域水文模型,拟合和验证期间模型的拟合度指数均有所提高,嫩江富拉尔基和大赉水文站控制流域的Nash-Sutcliffe系数和克林效率系数平均提高了3.08%和4.64%,均方根误差和相对偏差平均降低了12.72%和55.93%,且整个研究时段模拟结果的流量指数总体更接近于观测的径流数据。可见,耦合湿地模块的流域水文模型可提高水文过程模拟精度,更好地定量评估湿地水文功能,为流域水资源精准调控与湿地修复保护提供重要支撑。 相似文献
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通过网格定点法对我国东南沿海区域性台风危险性进行了分析。利用对各网格点有影响的历史台风数据,建立了各网格点的台风关键参数的最优概率模型。利用Monte-Carlo方法产生每个网格点1 000年间的虚拟台风事件。采用YanMeng(YM)风场模型模拟了100个历史台风的最大风速,通过使这些最大风速与观测的最大风速误差和最小,建立了一组新的计算最大风半径Rmax和Holland气压参数B的公式,结果表明新的台风参数计算方案效果良好。利用新的参数计算方案、YM风场模型、特定地点的台风衰减模型以及合适的极值分布模型,预测了各个网格点不同重现期的极值风速,进而绘制了台风多发区域的设计风速图。最后研究了不同B模型、Rmax模型和极值分布模型对预测的极值风速的影响。可以为结构抗风设计和台风防灾减灾提供新的参考。 相似文献
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