南渡江河口洪、枯季节水文泥沙变化特征及台风“海鸥”对入海水沙的影响   总被引：1，自引：0，他引：1  

陈斌  高飞  印萍  刘金庆 《海洋与湖沼》2015,46(6):1279-1291

基于2014年最新的洪、枯季节实测资料,分析了南渡江河口海域水文泥沙的季节性变化特征,借助台风"海鸥"过境期间的河道监测数据,研究了台风天气造成的洪水事件对河流入海水沙通量的影响。研究结果表明:(1)洪、枯季节河口海域的水体层化作用不强,洪季的水温高于枯季,但盐度低于枯季。水温呈现向海递减的趋势,而盐度整体分布较为均匀;(2)河口水体含沙量近岸大于远岸,枯季河口三角洲泥沙向西输运。洪季含沙量明显高于枯季,大量泥沙在台风季节被冲刷入海,而后向海或向西输运扩散;(3)河口海域为不规则全日潮,呈现东西向往复流特征。温度、盐度和浊度均呈现较强的潮汐性变化特征;(4)枯季河道内存在明显的盐水楔,锋面处的垂向梯度很大,在口门向陆大约12—15 km以远的河道水体不再受潮汐影响;(5)台风"海鸥"影响下,南渡江洪峰期间的径流量和含沙量均远远超过多年平均值,反映了南渡江河口地区"台风季节"的特点。  相似文献   

南海北部陆架区两个台风过境时近惯性运动的若干特征   总被引：2，自引：1，他引：1  

CHEN Shengli  HU Jianyu  POLTON Jeff A. 《海洋学报(英文版)》2015,34(1):38-43

Features of near-inertial motions on the shelf(60 m deep) of the northern South China Sea were observed under the passage of two typhoons during the summer of 2009. There are two peaks in spectra at both sub-inertial and super-inertial frequencies. The super-inertial energy maximizes near the surface, while the sub-inertial energy maximizes at a deeper layer of 15 m. The sub-inertial shift of frequency is induced by the negative background vorticity. The super-inertial shift is probably attributed to the near-inertial wave propagating from higher latitudes. The near-inertial currents exhibit a two-layer pattern being separated at mid-depth(25–30 m), with the phase in the upper layer being nearly opposite to that in the lower layer. The vertical propagation of phase implies that the near-inertial energy is not dominantly downward. The upward flux of the near-inertial energy is more evident at the surface layer(17 m). There exist two boundaries at 17 and 40 m, where the near-inertial energy is reflected upward and downward. The near-inertial motion is intermittent and can reach a peak of as much as 30 cm/s. The passage of Typhoon Nangka generates an intensive near-inertial event, but Typhoon Linfa does not. This difference is attributed to the relative mooring locations, which is on the right hand side of Nangka's path(leading to a wind pattern rotating clockwise with time) and is on the left hand side of Linfa's path(leading to a wind pattern rotating anti-clockwise with time).  相似文献   

Simulation of the extreme waves generated by typhoon Bolaven (1215) in the East China Sea and Yellow Sea     

JUN Ki Cheon  JEONG Weon Mu  CHOI Jin Yong  PARK Kwang Soon  JUNG Kyung Tae  KIM Mee Kyung  CHAE Jang Won  QIAO Fangli 《海洋学报(英文版)》2015,34(12):19-28

Record-breaking high waves occurred during the passage of the typhoon Bolaven (1215) (TYB) in the East China Sea (ECS) and Yellow Sea (YS) although its intensity did not reach the level of a super typhoon. Winds and directional wave measurements were made using a range of in-situ instruments mounted on an ocean tower and buoys. In order to understand how such high waves with long duration occurred, analyses have been made through measurement and numerical simulations. TYB winds were generated using the TC96 typhoon wind model with the best track data calibrated with the measurements. And then the wind fields were blended with the reanalyzed synoptic-scale wind fields for a wave model. Wave fields were simulated using WAM4.5 with adjustment of C_d for gust of winds and bottom friction for the study area. Thus the accuracy of simulations is considerably enhanced, and the computed results are also in better agreement with measured data than before. It is found that the extremely high waves evolved as a result of the superposition of distant large swells and high wind seas generated by strong winds from the front/right quadrant of the typhoon track. As the typhoon moved at a speed a little slower than the dominant wave group velocity in a consistent direction for two days, the wave growth was significantly enhanced by strong wind input in an extended fetch and non-linear interaction.  相似文献   

“菲特”台风路径和强度预报难点分析   总被引：1，自引：0，他引：1  

娄小芬  楼茂园  罗玲  范爱芬 《海洋预报》2015,32(1)

利用1°×1°NCEP再分析资料、NOAA海温资料对其进行分析,结果表明:(1)副高突然加强西进,中低层高压带加强,在台风北侧形成高压坝和强盛偏东气流,是台风路径突然西折的主要原因;(2)"丹娜丝"的活动在一定程度上阻止了副热带高压的南落,有利于副高南侧偏东急流的维持和加强,对"菲特"路径的突然西折起一定作用。敏感性数值试验结果表明"双台风"效应对"菲特"登陆前进一步西折具有决定作用;(3)高低空急流的配置,产生了动力场的耦合作用,加强了台风的对流活动,所释放的潜热可以补偿海温降低的影响,对"菲特"在近海强度维持起到了重要作用;(4)"菲特"的强度和环境风垂直切变的演变规律基本一致,较低的环境风垂直切变是"菲特"在近海强度维持的重要原因。  相似文献   

强台风下导管架平台倒塌全过程数值仿真     

朱本瑞  陈国明  林红  刘红兵  黄超 《海洋工程》2015,33(2):97-104

针对强台风引起的平台倒塌问题,综合隐式有限元与显式动力有限元算法,建立导管架平台结构倒塌全过程仿真流程;提出基于重现期的Pushover分析方法,充分考虑平台侧向环境载荷分布的变化以及可能的甲板上浪载荷因素,使得确定的倒塌环境载荷更加真实;采用APDL编制平台隐式与显式有限元模型转化程序,有效解决波浪载荷计算与精确施加的难题;在此基础上,应用LS-DYNA实现导管架平台在强台风载荷下的倒塌全过程仿真,动态再现平台结构倒塌过程中的构件破坏失效及内力分布,深入揭示平台结构的倒塌机理。研究成果可为导管架平台结构抗台风设计及理论研究提供参考。  相似文献   

热带季节内振荡对西北太平洋台风生成的大尺度环境的影响   总被引：1，自引：1，他引：0       下载免费PDF全文

周伟灿  沈海波  赵海坤 《大气科学学报》2015,38(6):731-741

基于澳大利亚气象局发布的RMM(Real-time Multivariate Madden-Julian oscillation)指数,将热带大气季节内振荡划分为8个位相,统计分析了各位相西北太平洋台风生成频数和位置的变化特征,并进一步利用BDI(Box Difference Index)指数分析了台风生成的活跃和不活跃位相之间环境要素的差别。结果表明,相比于台风生成的不活跃位相(1、2、3位相),在利于台风生成的活跃位相(5、6、7位相)期间,环境场具有更强的低层辐合和高层辐散外流、更高的对流层中层相对湿度和更广的垂直切变较小区域。进一步研究表明,在台风生成的活跃和不活跃位相之间,大尺度环境场的差别主要体现在动力因子方面,尤其是低层辐合场。  相似文献   

地形对台风“海葵”降水增幅影响的研究     

朱红芳  王东勇  娄珊珊  邱学兴 《湖北气象》2015,(2):160-167

使用NCEP GFS资料和WRF V3.4模式对2012年第11号台风"海葵"(1211)引发的安徽强降水过程进行数值模拟,通过改变模式中安徽省大别山区和皖南山区的地形高度,设计一组敏感性试验,对"海葵"降水的地形增幅效应进行研究。结果表明:(1)WRF模式对台风"海葵"降水过程有较好的模拟能力。(2)大别山区和皖南山区地形对"海葵"移动路径、强度以及降水分布、强度均有不同程度的影响;不同地形高度下模拟的台风路径及降水分布差异较大,且降水中心强度与地形高度相关性较好,地形对暴雨增幅作用明显。(3)山区地形有利于中尺度辐合线和低涡生成、发展,并有强水汽辐合中心与之相对应;有地形时对流层低层上升运动比无地形时明显加强,对安徽中南部强降水增幅作用显著。  相似文献   

Impact of Assimilating Radiances with the WRFDA ETKF/3DVAR Hybrid System on Prediction of Two Typhoons in 2012          下载免费PDF全文

XU Dongmei  HUANG Xiang-Yu  WANG Hongli  Arthur P. MIZZI  MIN Jinzhong 《Acta Meteorologica Sinica》2015,29(1):28-40

The impacts of AMSU-A and IASI (Infrared Atmospheric Sounding Interferometer) radiances assimila-tion on the prediction of typhoons Vicente and Saola (2012) are studied by using the ensemble transform ...  相似文献   

A diagnostic study of the asymmetric distribution of rainfall during the landfall of typhoon Haitang (2005)   总被引：1，自引：0，他引：1  

Caijun Yue  Shouting Gao  Lu Liu  Xiaofan Li 《大气科学进展》2015,32(10):1419-1430

The precipitation during landfall of typhoon Haitang (2005) showed asymmetric structures (left side/right side of the track). Analysis of Weather Research and Forecasting model simulation data showed that rainfall on the right side was more than 15 times stronger than on the left side. The causes were analyzed by focusing on comparing the water vapor flux, stability and upward motion between the two sides. The major results were as follows: (2) Relative humidity on both sides was over 80%, whereas the convergence of water vapor flux in the lower troposphere was about 10 times larger on the right side than on the left side. (5) Both sides featured conditional symmetric instability [MPV (moist potential vorticity) <0], but the right side was more unstable than the left side. (6) Strong (weak) upward motion occurred throughout the troposphere on the right (left) side. The Q vector diagnosis suggested that large-scale and mesoscale forcing accounted for the difference in vertical velocity. Orographic lift and surface friction forced the development of the asymmetric precipitation pattern. On the right side, strong upward motion from the forcing of different scale weather systems and topography caused a substantial release of unstable energy and the transportation of water vapor from the lower to the upper troposphere, which produced torrential rainfall. However, the above conditions on the left side were all much weaker, which led to weaker rainfall. This may have been the cause of the asymmetric distribution of rainfall during the landfall of typhoon Haitang.  相似文献   

登陆台风边界层风廓线特征的地基雷达观测   总被引：2，自引：0，他引：2  

赵坤  王明筠  朱科锋  明杰  马秀梅  王元 《气象学报》2015,73(5):837-852

为了分析登陆台风边界层风廓线特征,利用2004—2013年中国东南沿海新一代多普勒天气雷达收集的17个登陆台风资料,采用飓风速度体积分析方法,反演登陆台风的边界层风场结构特征。与探空观测对比表明,利用雷达径向风场可以准确地反演登陆台风的边界层风场结构,其风速误差小于2 m/s,风向误差小于5°。所有登陆台风合成的边界层风廓线显示,在近地层(100 m)以上,边界层风廓线存在类似急流的最大切向风,其高度均在1 km以上,显著高于大西洋观测到的飓风边界层急流高度(低于1 km)。陆地边界层内低层入流强度也明显大于过去海上观测,这主要是由陆地上摩擦增大引起。越靠近台风中心,边界层风廓线离散度越大,其中,径向风廓线比全风速以及切向风廓线离散度更大。将风廓线相对台风移动方向分为4个象限,分析边界层风廓线非对称特征显示,台风移动前侧入流层明显高于移动后侧。最大切向风位于台风移动左后侧,而台风右后侧没有显著的急流特征,与过去理想模拟的海陆差异导致的台风非对称分布特征一致。  相似文献