排序方式： 共有6条查询结果，搜索用时 15 毫秒
1
1.
基于挪威南森环境遥感中心改进的NERSC-HYCOM 模式, 利用单向嵌套技术与欧洲中心提供的2008 年ERA-I 高分辨率强迫场针对东中国海及其邻近海区进行了不同垂向坐标配置的四个敏感性试验。通过分析东中国海区域的温度、盐度, 流速的分布和变化, 探讨了HYCOM 模式中不同垂向坐标设置对东中国海近岸区域的影响以及黑潮流速及路径对不同坐标设置的响应, 期望对HYCOM 模式更深入的研究提供参考。结果表明: (1)在东中国海区上层并不适于采用等密度坐标方案, 也就是说应该采用z坐标或σ坐标用以表征此处混合层的季节性变化特征; (2)针对东海大陆架区给出了10 个位置上的模式与浮标观测资料的温、盐平均误差(ME)、均方根差(RMS)及相关系数(R)指标, 发现对于不同区域, 每种试验的适用性都不同; (3)使用高频资料时, 模拟的流速普遍偏高, 东海黑潮冬夏路径的异同指出了σ-z-iso 与z-iso 试验模拟效果较好, 但模拟的日本岛南岸的弯曲流场位置偏南; 而z-only 试验模拟的日本岛以南的黑潮路径是有所改观的, z坐标的分辨率对表层的黑潮路径影响很大; σ-only 试验模拟的整个黑潮路径的效果最差。 相似文献
2.
The Eulerian?Lagrangian method (ELM) has been used by many ocean models as the solution of the advection equation, but the numerical error caused by interpolation imposes restriction on its accuracy. In the present study, hybrid N-order Lagrangian interpolation ELM (LiELM) is put forward in which the N-order Lagrangian interpolation is used at first, then the lower order Lagrangian interpolation is applied in the points where the interpolation results are abnormally higher or lower. The calculation results of a step-shaped salinity advection model are analyzed, which show that higher order (N=3?8) LiELM can reduce the mean numerical error of salinity calculation, but the numerical oscillation error is still significant. Even number order LiELM makes larger numerical oscillation error than its adjacent odd number order LiELM. Hybrid N-order LiELM can remove numerical oscillation, and it significantly reduces the mean numerical error when N is even and the current is in fixed direction, while it makes less effect on mean numerical error when N is odd or the current direction changes periodically. Hybrid odd number order LiELM makes less mean numerical error than its adjacent even number order LiELM when the current is in the fixed direction, while the mean numerical error decreases as N increases when the current direction changes periodically, so odd number of N may be better for application. Among various types of Hybrid N-order LiELM, the scheme reducing N-order directly to 1st-order may be the optimal for synthetic selection of accuracy and computational efficiency. 相似文献
3.
基于2002—2011年共10 a的AMDAR资料,用于中国周边海域(0~35°N,110~150°E)越洋飞行飞机颠簸的时空分布和变化规律分析。研究指出:南海比西北太平洋海域更容易发生重度以上的飞机颠簸;全年中6月最容易发生颠簸,而9月至次年2月发生重度和严重颠簸的百分率明显减小;5 km以下,发生轻度和重度颠簸的百分率随高度增大而减小,8 km以上重度颠簸的发生百分率稳定在0.2%左右,边界层顶和对流层顶附近容易发生严重颠簸,发生的百分率分别为0.27%和0.18%;随着风速增大发生颠簸的概率一般也增大,在对流层上层风速大于40 m/s时,发生重度和严重颠簸的百分率都明显增大,达到0.2%左右。冷半年风向为NNE以及暖半年风向为SSW时,发生重度颠簸的百分率达4%左右;严重颠簸发生在暖半年的概率较大,暖半年吹SSE至ESE风时,发生百分率为0.25%~0.3%,但暖半年吹正北风或冷半年吹正南风时,也易发生严重颠簸。 相似文献
4.
结合AVISO(Archiving Validation and Interpolation of Satellite Oceanographic Data)高度计资料,利用改进的NERSCHYCOM(Nansen Environmental and Remote Sensing Center-Hybrid Coordinate Ocean Model)大洋环流模式,对南海中尺度涡进行数值模拟研究,主要包括中尺度涡的三维结构、南海EKE(Eddy Kinetic Energy,涡动动能)的垂向变化、黑潮中尺度涡的脱落以及涡旋近岸时的结构变化等。模式再现了2007年2月-3月菲律宾西侧海域的一次暖涡过程,探究了其生命期中各阶段的特征物理量的变化,对其成熟时期的涡旋结构研究表明,中尺度涡的结构呈现不对称性,涡旋两侧的流场空间范围和流场强度均不相同,涡旋的半径和中心位置随深度不断变化,并且由涡旋作用产生的升降流的中心与涡旋自身中心并不重合,二者之间有一定距离。初步探索EKE的垂向分布情况,认为南海年平均EKE在垂向变化上呈现三段式,主要部分分布在300m以浅深度,但同时垂向又能达到海洋深层。分析了一次黑潮中尺度涡脱落的模式模拟个例,推测黑潮中尺度涡脱落原因:黑潮流径西移、外海中尺度涡对黑潮的强迫、地形作用,并且结果表明从黑潮脱落的中尺度涡可以携带大量高温高盐水体进入南海,对南海的温盐性质产生很大的影响。初步探索涡旋近岸时的结构变化,涡旋靠近岸界时,受岸界挤压,流速在一段时间内会增大,继续靠近岸界,由于岸界的摩擦、海底的拖曳,导致能量耗散,流速减小,最终涡旋消亡。 相似文献
5.
采用WRF v3模式, 利用AMDAR资料与NCEP再分析资料, 对2007年发生于南海周边海域的高空越洋航线上, 110个中度以上晴空颠簸事例与196个无颠簸事例进行数值模拟。选取布朗指数、水平风切变指数等6个晴空颠簸诊断指数, 通过计算各指数的有颠簸诊断准确率、无颠簸诊断准确率、TS评分、ETS评分等指标, 研究指数及其阈值的适用性。研究表明:(1)布朗指数是诊断南海周边海域越洋航线上的晴空颠簸的最佳指数, 并在取"3.2×10-5"为阈值时诊断效果最佳。(2)南海周边海域的越洋航线上的晴空颠簸对于诊断指数阈值的选取十分敏感, 在晴空颠簸的数值预报中, 在合理选择指数的基础之上, 应当认真研究设定指数的阈值。 相似文献
6.
The Eulerian-Lagrangian method (ELM) has been used by many ocean models as the solution of the advection equation, but the numerical error caused by interpolation imposes restriction on its accuracy. In the present study, hybrid N-order Lagrangian interpolation ELM (LiELM) is put forward in which the N-order Lagrangian interpolation is used at first, then the lower order Lagrangian interpolation is applied in the points where the interpolation results are abnormally higher or lower. The calculation results of a step-shaped salinity advection model are analyzed, which show that higher order (N=3-8) LiELM can reduce the mean numerical error of salinity calculation, but the numerical oscillation error is still significant. Even number order LiELM makes larger numerical oscillation error than its adjacent odd number order LiELM. Hybrid N-order LiELM can remove numerical oscillation, and it significantly reduces the mean numerical error when N is even and the current is in fixed direction, while it makes less effect on mean numerical error when N is odd or the current direction changes periodically. Hybrid odd number order LiELM makes less mean numerical error than its adjacent even number order LiELM when the current is in the fixed direction, while the mean numerical error decreases as N increases when the current direction changes periodically, so odd number of N may be better for application. Among various types of Hybrid N-order LiELM, the scheme reducing N-order directly to 1st-order may be the optimal for synthetic selection of accuracy and computational efficiency. 相似文献
1