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以运动坐标系中的海浪谱为靶谱应用静止坐标系中随机波面的模拟方法─—线性叠加法和线性过滤法模拟匀速运动坐标系中的随机波面,给出了两种方法的原理及模拟手续。通过模拟实验发现,在高速运动的坐标系中线性叠加法优于线性过滤法,在低速情形,线性过滤法好于线性叠加法,并在模拟技术上给出了各参数的选取方法。 相似文献
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利用1951—2012年日本气象厅(JMA)热带气旋(TC)最佳路径资料,分析了影响南海的土台风和非局地台风62 a间的时空分布特征,比较了二者在时空分布上的差异性,得到以下主要结果:土台风源地位置与热带季风性气候有关,夏季风时主要在15°N以北,冬季风时向15°N以南移动;土台风与非局地台风相比,活动范围更广,但强度比后者弱;土台风在南海的强度发展过程呈对称曲线形式,非局地台风则是一条递减曲线;土台风和非局地台风的登陆位置都具有季风期规律,夏季风时登陆的TC比冬季风时登陆的多得多,同纬度的非局地台风比土台风移动速度大。 相似文献
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在南海北部,与中尺度涡相关的季节内变异特征十分显著,通过比较不同时期流场的季节内变异特征,有助于揭示不同动力不稳定中尺度涡对季节内活动的影响。本文以南海北部2009年春季和2020年春季为例,分析了两个时期中尺度涡的动力不稳定性,从而探究季节内变异特征。基于潜标实测流速数据,本文进行了动能谱分析,结果显示这两个时期的流场季节内变异具有相似特征,显著周期分别为10~60 d和30~90 d。季节内信号主要出现在200 m以上的上表层水域,其中30~90 d的季节内流是对应观测期间的主要季节内成分。滞后回归分析和动力不稳定性的计算表明,2009年春季的季节内变异受移动快但强度弱的表层中尺度涡影响,动力不稳定性由斜压不稳定和正压不稳定共同调制;而2020年春季的季节内变异是受强斜压性的中尺度涡影响,通过流速垂向切变增强,从而较快地触发流场季节内变异的发生。本文研究结果有助于深入了解中尺度涡对南海北部季节内活动的影响机制,为海洋动力学和气候研究提供了重要的参考和理论基础。 相似文献
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Effects of surface waves and sea spray on air–sea fluxes during the passage of Typhoon Hagupit 总被引:2,自引:1,他引:2
Air–sea exchange plays a vital role in the development and maintenance of tropical cyclones(TCs). Although studies have suggested the dependence of air–sea fluxes on surface waves and sea spray, how these processes modify those fluxes under TC conditions have not been sufficiently investigated based on in-situ observations.Using continuous meteorological and surface wave data from a moored buoy in the northern South China Sea,this study examines the effects of surface waves and sea spray on air–sea fluxes during the passage of Typhoon Hagupit. The mooring was within about 40 km of the center of Hagupit. Surface waves could increase momentum flux to the ocean by about 15%, and sea spray enhanced both sensible and latent heat fluxes to the atmosphere,causing Hagupit to absorb 500 W/m~2 more heat flux from the ocean. These results have powerful implications for understanding TC–ocean interaction and improving TC intensity forecasting. 相似文献
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The quasi-biweekly oscillation (QBWO) is the second most dominant intraseasonal mode for circulation over
the Northwestern Pacific (WNP) during boreal summer. In this study, we investigated how the QBWO modulates
tropical cyclone (TC) activities over the WNP from dynamic and thermodynamic perspectives. The propagation of the
QBWO can be divided into four phases through empirical orthogonal function analysis of the vorticity at 850 hPa, which
was proven to be effective in extracting the QBWO signal. TC generation and landings are significantly enhanced during
the active period (phases 1 and 2) relative to the inactive period (phases 3 and 4). Composite analyses show the QBWO
could significantly modulate TC activity as it propagates northwestward by changing the atmospheric circulation at both
high and low levels. Cumulus convection provides an important link between TCs and the QBWO. The major
component of the atmosphere heat source is found to be the latent heat release of convection. The condensation latent
heat centers, vertical circulation, and water vapor flux divergence cooperate well during different phases of the QBWO.
The vertical profile of the condensation latent heat indicates upper-level heating (cooling) during the active (inactive)
phases of the QBWO. Thus, the northwestward propagation of the QBWO can modulate TC activity by affecting the
configuration of atmospheric heating over the WNP. 相似文献
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基于Galieo变换,导出了运动坐标系与静止坐标系中海浪谱间的关系。由于海浪是频散的,两者间的关系是频率相关的。运动坐标系中的海浪频谱是与静止坐标系中的海浪方向谱相联系的。以文氏谱作为静止坐标系中的海浪频谱,给出了不同速度下运动坐标系中的海浪频谱。 相似文献
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中国多金属结核开辟区的深海环境 总被引:7,自引:0,他引:7
阐述了中国多金属结核开辟区深海环境的水文、生物和化学特征。开辟区海域水柱由表层混合层、温跃层、海底温跃层和海底边界层等不同水层构成,整个海域水动力条件总体上较为缓慢,但也存在着周期性的水流速度大于15cm/s的海底风暴;区内海底生态系统的显著特点是极低的生产力和生物过程速率,但生物多样性极高;整个区域内表层沉积物分布较均一,以低有机含量的硅质粘土、深海软泥为主,其化学组成上受沉积环境和早期成岩作用的影响和控制。 相似文献