The Origin of the Water-Gaps on the Yangtze and Chialing Rivers     

S.TING 《地质学报》1944,(Z2):256-270

正 INTRODUCTION Ⅰ.General Principles Theoretically speaking, under the normal cycle of erosion rivers tend to adjust themselves to structure as the cycle advances and complete adjustment should  相似文献   

杭州湾大型底栖动物季节分布及环境相关性分析   总被引：2，自引：1，他引：1  

寿鹿  曾江宁  廖一波  高爱根  徐颋  杨家新  陈全震 《海洋学报》2012,34(6):151-159

对杭州湾大型底栖动物进行了夏(2006年7-8月)、冬(2006年12月-2007年1月)、春(2007年4月)、秋(2007年10-11月)季调查,分析了大型底栖动物的季节分布及其与环境的关系。结果表明:本海域四季共鉴定出113种大型底栖动物,多毛类、软体动物和甲壳类是该海域大型底栖动物的主要类群;主要优势种为双鳃内卷齿蚕、西方似蛰虫和多鳃卷吻沙蚕等多毛类。方差分析表明,除甲壳类丰度外,杭州湾大型底栖动物群落参数无显著季节差异,群落分析表明,杭州湾群落特点比较单一,未分辨出显著差异的群落;丰度/生物量比较法分析表明,秋季杭州湾海域受到了污染的扰动;典范对应分析表明,多毛类主要受物理因子(如温度、盐度、水深等)影响,而软体动物、甲壳类和其他类动物主要受生物化学因子(如叶绿素、总有机碳、浮游生物等)影响。从典范对应分析的结果,可以推断出杭州湾大型底栖动物受自然环境特征的影响较人类活动的影响大。  相似文献   

Impulsive force of debris flow on a curved dam   总被引：8，自引：0，他引：8  

Chjeng-Lun SHIEH  Chia-Hsien TING  Hung-Wen PAN 《国际泥沙研究》2008,23(2):149-158

Although Sabo dams are an efficient method for river and basin management, traditional Sabo dams have a great impact on ecology and landscape. Moreover, such dams are hit and often damaged by great impulsive force when they block the debris flow. Therefore, alternative shapes for Sabo dam deserve thorough investigation. In this investigation, a curved dam was designed by changing the upstream-dam-surface geometric shape to reduce the impulsive force of the debris flow, with enhanced stability and reduced concrete mass being the anticipated outcomes. In this study, the flume and laboratory facilities simulated the impulsive force of the debris flow to the Sabo dams. Three geometric forms, including vertical, slanted and curved Sabo dams, were used to determine the impulsive force. Impulsive force theories of the debris flow were derived from the momentum equation and the Bernoulli equation. In these, the impulsive force was balanced by the friction force of the Sabo dam and the opposite force of the load cell behind the dam as it was hit by the debris flow. Positive correlations were found when comparing the experimental data with the theoretical results. These findings suggest that our impulsive force theory has predictive validity with regard to the experimental data. The results from both theory and experimental data clearly show that curved darns were sustained less force than the other darns under the same debris flow. This comparison demonstrates the importance of curved geometry for a well-designed Sabo dam.  相似文献   

大气能量传播及不同纬度间大气相互作用的研究进展   总被引：1，自引：0，他引：1       下载免费PDF全文

杨崧  邓开强  TING Mingfang  胡春迪 《Acta Meteorologica Sinica》2015,73(6):999-1018

早期的理论分析认为大气中临界纬度的存在使得热带-热带外的大气活动互不影响。然而,大量的观测事实表明中低纬度大气运动存在着明显的动力联系。为了帮助人们更好地理解大气中的遥相关现象,在大量文献的基础上,综述了几种波能量传播理论:(1) 大圆理论指出了罗斯贝波在球形大气中的传播特征;(2) 西风通道理论发现了中纬度瞬变扰动越赤道传播的“走廊”;(3) 能量堆积-波列发射理论揭示了热带扰动影响到更高纬度大气活动的可能过程;(4) 赤道波侧向膨胀理论则利用转折纬度的概念更进一步解释了这种中低纬度大气相互作用的物理机制;(5) 经向基本流理论则认为在一定的条件下定常波可以穿过热带东风带传播到另一半球。此外,文中还回顾了在波-流相互作用诊断方面的研究进展,尤其是关于罗斯贝波、惯性重力波和赤道开尔文波。大气能量的经向传播具有显著的年变化和年际变化,这与ENSO、西风急流、大洋中部槽等的变化密切相关。  相似文献   

Advances in research on atmospheric energy propagation and the interactions between different latitudes     

杨崧  邓开强  丁敏芳  胡春迪 《Acta Meteorologica Sinica》2015,29(6):859-883

Early theoretical analyses indicated that the tropics and extratropics are relatively independent due to the existence of critical latitudes. However, considerable observational evidence has shown that a clear dynamical link exists between the tropics and midlatitudes. To better understand such atmospheric teleconnection, several theories of wave energy propagation are reviewed in this paper: (1) great circle theory, which reveals the characteristics of Rossby waves propagating in the spherical atmosphere; (2) westerly duct theory, which suggests a “corridor” through which the midlatitude disturbances in one hemisphere can propagate into the other hemisphere; (3) energy accumulation-wave emanation theory, which proposes processes through which tropical disturbances can affect the atmospheric motion in higher latitudes; (4) equatorial wave expansion theory, which further explains the physical mechanisms involved in the interaction between the tropics and extratropics; and (5) meridional basic flow theory, which argues that stationary waves can propagate across the tropical easterlies under certain conditions. In addition, the progress made in diagnosing wave-flow interaction, particularly for Rossby waves, inertial-gravity waves, and Kelvin waves, is also reviewed. The meridional propagation of atmospheric energy exhibits significant annual and interannual variations, closely related to ENSO and variation in the westerly jets and tropical upper-tropospheric troughs, amongst others.  相似文献   

通用气象业务电子化考试系统的设计技术     

李宇中  甘一忠  董良淼  徐明芳 《气象科技》2012,40(3):388-393

针对传统纸质考试和常规无纸化考试系统在气象业务应用中存在的一些不足,提出了一种基于Excel电子表格系统的通用气象业务电子化考试平台方案。系统采用嵌入式VBA语言进行模块化程序设计,具备标准无纸化考试系统的绝大部分功能,实际应用表明具有低成本、易维护、适用性强等优点,有较好的推广应用前景。文章详细介绍了该平台的概念模型设计及其主要功能模块的实现,并分析了模块研发过程中需要注意的问题和系统进一步扩展完善的思路。  相似文献   

Silver and lead in high-altitude lake sediments: Proxies for climate changes and human activities     

Marion Garçon  Catherine Chauvel  Emmanuel Chapron  Xavier Faïn  Mingfang Lin  Sylvain Campillo  Sarah Bureau  Marc Desmet  Marie-Christine Bailly-Maître  Laurent Charlet 《Applied Geochemistry》2012

High-altitude lake sediments are often used as archives for environmental changes and their chemical and isotopic compositions provide significant constraints on natural and anthropogenic long-term changes that have occurred in their catchment area. Here, trace-element concentrations and Pb isotopes are presented for two sedimentary cores from Lake Blanc Huez in the French Alps, to trace the impact of climate changes and human activities over the Holocene. Lead and Ag contents are very high and clearly dominated by input from a Pb–Ag vein located a few meters from the lakeshore, a vein that also buffers the Pb isotopes. Mining of this vein in medieval times is recorded in the corresponding lake sediments with high Ag content coupled with high Pb/U ratio. These chemical characteristics can be used to constrain the major Holocene climate changes. Significant advances of glaciers next to the lake produced sediments with Ag and Pb concentration peaks and high Pb/U ratios due to accelerated erosion of the Pb–Ag vein, similar to the effects of the medieval mining. In contrast, reduced glacier activity led to the formation of organic-rich sediments with high U and As contents and low Pb/U ratios. More generally, the observed combination of chemical changes could be used elsewhere to decipher environmental changes over long periods of time.  相似文献   

Capacitive sensing technique for silt suspended sediment concentration monitoring     

Yin-Sung HSU Chi-ma WEI Yuan-Chi TING Shih-Yi YUAN Chia-Ling CHANG Kao-Chung CHANG 《国际泥沙研究》2010,25(2):175-184

Automated, real-time, and continuous techniques for monitoring suspended sediment concentration in rivers and reservoirs can play an important role in the improvement of the quantity and quality of sediment data, and are valuable to the management of water environment, water conservancy, hazard prevention, and water resources. Research in the monitoring techniques has examined the possibility of using the characteristics of dielectric constants for detecting soil moisture and concentration of air-water two-phase flow, based on the fact that dielectric constants of sediment, air and water are different. A capacitance sensor was developed to monitor the silt suspended sediment concentration (SSSC) in a recent study, following the principle that as SSSC increases in the sediment-water mixture, the apparent dielectric constant of the water sample also increases and therefore the capacitance detected by the sensing system also increases. It is demonstrated that the variations in the concentration of silt sediment correlates positively with the variations in observed capacitance in a linear fashion, and correlates negatively with voltage outputs but also in a linear fashion. The correlation coefficients reached above 0.98. The overall errors in estimated concentrations range between 0.26% and 2.91%. Elements in the capacitance sensor system such as the frequencies of the signal generating system, areas of the electrode plates, and effects of sample temperature have also been evaluated. The results illustrated that the capacitance sensor techniques can be applied to monitoring SSSC automatically and continuously. Also, the range of SSSC in the experiment reached 200 kg/m³; therefore, the application of this technique in practical SSSC monitoring is worthy of further research.  相似文献   

On the Causes of Climatic Change and the Last Quaternary Glaciation in Asia     

TING YING H.MA 《地质学报》1940,(Z1)

The geological events happened since the beginning of the building of theraised coral reefs may be summarized as follows: 1. The period of the formation of raised coral reefs seems to coincidewith the last interglacial stage, at least in Asia. This will be termed the"Tateyama Reef Stage." In this period it was not the climate of the wholeworld, but the location of latitude that was different from that of present.Latitudes of places in Asia were about 5 degrees nearer to the equator than theyare now. The...  相似文献   

On the Water Temperature of the Western Pacific During Early and Late Plestocene as Deduced from the Growth Rate of Fossil Corals     

TING YING H.MA 《地质学报》1938,(Z1)

Some years have elapsed since I began my studies on both fossil andrecent reef-building corals.Intensive as well as extensive investigations  相似文献