Marine Upper Triassic Fossils from Kochiu, Yunnan

INTRODUCTION The material which forms the present study is collected by Messrs.H. M. Meng, K. Chern and T. Ho from the village of Hopachung, near Kochiu,Yunnan province. According to them, the fossils are recorded from seven localities.     

Bragg Reflection of Waves by Different Shapes of Artificial Bars

Experiments are performed in a wave flume to demonstrate the Bragg reflection of linear gravity waves by artificial bars. Three different artificial bars with rectangular, triangular and rectified cosinoidal shapes are placed discretely on the seabed for measurement of the Bragg reflection. A series of experimental conditions including the number of bars, the pe-riodic bar spacing, the water depth and various wave conditions are tested. Key parameters influencing the Bragg resonances are investigated. The experimental data are compared with the values from both theoretical and numerical models. Some key parameters have proved to be effective in describing the primary resonances. Predictive equations of the charac-teristics for the Bragg reflection are proposed in this paper.     

Oceanic pycnocline depth retrieval from SAR imagery in the existence of solitary internal waves

Oceanic pycnocline depth is usually inferred from in situ measurements. It is attempted to estimate the depth remotely. As solitary internal waves occur on oceanic pycnocline and propagate along it, it is possible to retrieve the depth indirectly in virtue of the solitary internal waves. A numerical model is presented for retrieving the pycnocline depth from synthetic aperture radar （SAR） images where the solitary internal waves are visible and when ocean waters are fully stratified. This numerical model is constructed by combining the solitary internal wave model and a two-layer ocean model. It is also assumed that the observed groups of solitary internal wave packets on the SAR imagery are generated by local semidiurnal tides. A case study in the East China Sea shows a good agreement with in situ CTD （conductivity-temperature-depth） data.     

Using an integrated model to track the fate and transport of suspended solids and heavy metals in the tidal wetlands

An integrated two-dimensional depth-average numerical model was developed to simulate hydrodynamics and to track the fate and transport of contaminants in the Erh-Chung Flood Way wetland in northem Tai...     

卫星重力梯度恢复地球重力场的频谱分析

根据仪器功率谱密度和重力位系数阶方差的定义,本文建立了卫星重力梯度测量噪声功率谱密度与重力场模型的误差阶方差的直接对应关系,并基于此讨论了重力梯度测量精度、卫星轨道高度以及运行时间对地球重力场恢复精度的影响.相比于传统的基于最小二乘法评估卫星载荷噪声对地球重力场恢复精度的影响而言,本文提出的方法简单、直接,有助于快速设计和确定卫星重力测量计划的有关参数.     

Erosion control for mudstone soil with ventilation and watertight resin

To accelerate the re-vegetation of exposed landslide areas, hydroseeding for soil and water conservation has been widely applied as one of the economically feasible ways. However, effect durations of different hydroseeding materials are different, the formulation density has a certain effect on plant growth and the addictives may exude. This paper presents laboratory experiments of soil erosion, exuding water quality and soil hardness by using a rainfall simulator with different conditions of slope, rainfall intensity and medication density. The results showed that soil erosion decreased significantly, suggesting a good erosion-resisting effect by the ventilation and watertight resin. No significant variation of the exuded water was observed during testing, which indicates that after gelling, the ventilation and watertight resin are unlikely to release chemical substances. It was found that high resin density will result in poor workability as well as high costs; adverse will cause the mudstone to fracture due to raindrops since cracks are common to soil surface. The weatherability after spraying and its effect on plant vegetation still need further investigation.     

起伏条件下重力碰并造成的暖性薄云降水

本文中考虑了云中垂直气流的湍流起伏,来計算云滴的碰并增长.发現在这种上升气流有起伏的环境下,同样大小的云滴在云中可以长成不同大小的較大云滴,包括降水胚滴和降水微元(雨滴),从而对暖性薄云如何形成降水給出一个此較合理的解释。     

夏季东亚热带和副热带地区经向和纬向环流型的特征

根据1958年7月8—18日和1957年7月21—30日东亚低纬度的两个悬殊的环流型,分析了在这两个时期内东亚低纬度环流的各种特征。结果得出,在经向和纬向环流期间,无论北半球纬向风带的位置,长波系统的配置,副热带高压活动的情况以及赤道辐合区的分布都有着很大的不同。此外,台风活动的次数也表现有很大悬殊。其所以有如此悬殊,可以从该两时期低纬度流场的特点来说明原因。在中国大陆上,在这两个时期的天气过程也很不同,在经向环流期间,大陆上的主要雨带成东北—西南向的,而在纬向环流期间,雨带便成东西向分布,并集中在江淮流域之间。 另外,我们又研究了在这两个时期内南北半球间环流关系,从手头所掌握的资料分析结果看,两者关系相当密切。在东亚低纬度经向环流期间,南半球(特别在澳洲)也盛行经向环流,并且在澳洲附近从南半球向北半球的质量输送也最强烈;而在东亚低纬度纬向环流期间,南半球也盛行纬向环流,澳洲附近的冷空气活动不显著,越过赤道向北的质量输送也比较弱。     

Energetic processes regulating the strength of MJO circulation over the Maritime Continent during two types of El Ni?o

不同类型的El Ni?o事件对海洋性大陆区域的MJO强度有显著的影响。其中,中太平洋型(CP)El Ni?o期间的秋冬季MJO环流在海洋性大陆区域变得更强。本文推导了新的MJO动能诊断方程,并以此来定量诊断两类El Ni?o期间调控海洋性大陆区域的MJO环流强度的物理过程。与EP El Ni?o相比,CP El Ni?o期间平均动能与MJO动能之间的正压能量转换增强。在CP El Ni?o期间,沃克环流在海洋性大陆区域出现上升异常、低层辐合和气旋异常,透过正压能量转换,MJO得以从平均气流场中获得较多的动能;并进一步透过斜压能量转换,来维持MJO自身的强度增长。CP El Ni?o期间,增强的MJO将其动能转给高频扰动,有利海洋性大陆区域的高频扰动发展。     

Seasonal evolution of the intraseasonal variability of China summer precipitation

Climate Dynamics - Seasonal cycle of China summer precipitation has significant impacts on its subseasonal predictability; yet current understanding of seasonal evolution of the intraseasonal...