Generation of oceanic internal gravity waves by a cyclonic surface stress disturbance

Atmospheric cyclones with strong winds significantly impact ocean circulation, regional sea surface temperature, and deep water formation across the global oceans. Thus they are expected to play a key role in a variety of energy transport mechanisms. Even though wind-generated internal gravity waves are thought to contribute significantly to the energy balance of the deep ocean, their excitation mechanisms are only partly understood.The present study investigates the generation of internal gravity waves during a geostrophic adjustment process in a Boussinesq model with axisymmetric geometry. The atmospheric disturbance is set by an idealized pulse of cyclonic wind stress with a Rankine vortex structure. Strength, radius and duration of the forcing are varied. The effect upon wave generation of stratification with variable mixed-layer depth is also examined.Results indicate that internal gravity waves are generated after approximately one inertial period. The outward radial energy flux is dominated by waves having structure close to vertical mode-1 and with frequency close to the inertial frequency. Less energetic higher mode waves are observed to be generated close to the sea floor underneath the storm. The total radiated energy corresponds to approximately 0.02% of the wind input. Deeper mixed-layer conditions as well as weaker stratification reduce this fraction.The low energy transfer rates suggest that other processes that drive vertical motion like surface heat fluxes, turbulent motion, mixed region collapse and storm translation are essential for significant energy extraction by internal gravity waves to occur.     

Fishing safety policy and research

Fishing has been and is still one of the most dangerous of all human activities. In the field of fishing safety policy, it is acknowledged that the development of a working legal framework of reference is a vital prior condition for the implementation of measures aimed at its improving safety. However, the research work on fishing safety does not have at disposal records of a sufficient number of accidents and in most cases is not comparable from one country to another. Moreover, there is no work that focuses on a global view of fishing safety. The aim of the present work is to outline the state-of-the-art in fishing safety. To this end, aspects of fishing safety which are a major concern of institutions, organizations and researchers alike are analysed. Thus, several questions are addressed, such as: what institutional policy is given to the activity of the fishing sector to improve safety; what aspects and/or parameters are normally used to analyse fishing accidents; what is the usual spatial domain of this analysis; and what are the topics of the research carried out in fishing safety? The results of this analysis, among other aspects, identify eight specific lines of research followed in fishing safety and five which deal with aspects of safety at sea related to the fishing sector.     

DZJ2激光垂准仪使用方法及指标的校正

介绍了DZJ2激光垂准仪的性能及基本指标的校正方法,为用户在使用DZJ2激光垂准仪过程中几种基本指标参数的校正提供参考.     

导线网坐标差观测值相关平差方法研究

提出了利用普通间接平差和相关间接平差两种平差方法相结合,进行以坐标差作为观测值进行导线网相关平差的方法.在该平差方法中,利用普通的简介平差原理推求出坐标差观测值的相关协因数阵,并以此作为已知数据进行以坐标差观测值作为观测值的导线网的相关平差.     

MATLAB软件在测量平差中的应用

阐述了如何利用 MATLAB软件处理观测数据。 MATLAB是目前在大学和研究机构广泛应用的一种数值计算及图形工具软件 ,它的特点是语法结构简明 ,数值计算高效 ,图形功能完备 ,特别适合非专业编程人员完成数值计算、科学试验数据处理等任务。给出了一个水准网无约束平差算例及其源程序     

Responding to Global Warming: Mitigation Policies and Actions of Stakeholders in China’s Tourism Industry

China’s tourism industry has witnessed rapid progress in recent years, and is now an important part of global tourism in dealing with climate change. Within a framework of Pressure-State-Response (PSR), this paper focuses on the emission reduction pressure, carbon emission status, and responses of stakeholders in China’s tourism industry. Findings include: 1) The central government’s strategy and rapid growth of the industry scale exert rising pressure on China’s tourism to reduce carbon emissions. 2) Carbon emissions of China's tourism account for 13%-14.6% of global tourism, and about 3% of China’s emissions overall. Chinese tourists’ per capita carbon emission is lower than half of the global level. 3) The Chinese government attaches great importance to energy-saving and carbon emission reduction. In the tourism industry, documents, standards and other regulative measures have been issued to ensure that business practitioners set up green operational and managerial systems. In the field of tourism transportation, China's high-speed rail, new energy vehicles, and urban shared bicycles, have developed very rapidly in recent years, and they have effectively reduced the carbon emissions in traveling. Furthermore, this paper finds that Chinese tourists already have awareness and willingness for low-carbon tourism.     

基于椭球不确定性的平差模型与算法

测量平差模型中的参数通常存在一些不确定的附加信息或先验信息,充分利用它们可以对部分参数进行约束,从而保证参数解的唯一性和稳定性。本文利用椭球集合描述不确定性,建立了一个新的带有椭球不确定性的平差模型。以两个椭球交集的外接椭球的特征矩阵的迹最小平差准则,分析了不确定度的传播规律,给出了带有椭球不确定性的平差方法。最后,通过算例验证了算法的有效性,说明了平差解与带权混合估计的关系。     

粒子加速器中高精度丝线绝对位置测量技术研究

粒子加速器中采用振动线技术进行共架单元上多块磁铁的高精度预准直,需要将振动线代表的磁中心引出进行共架单元之间的相对准直。为了获取以振动线为代表的丝线高精度空间绝对位置,本文对采用近景摄影测量技术进行点、线位置求解的方法进行了研究。利用单相机多站位的方法进行拍摄,通过标定板提供的高精度控制点坐标,采用自标定光束法平差对相机进行标定,并提出将空间直线离散成空间2点进行直线整体精确求解。对标定板上由2点组成的模拟直线进行测量验证,并与标定板提供的理论值进行对比,结果显示空间直线位置获取精度优于5 μm。这表明了本文理论和方法的正确性,为进一步研究丝线高精度空间绝对位置测量打下了基础。     

基于仿射变换的数字影像内定向的误差控制分析

数字化摄影测量生产中的误差来源众多,尤其是系统误差常常很突出。针对这个问题,首先深入分析了附有未知数的仿射变换控制模型参数的误差估计,然后利用误差传播定律和误差综合原理,推导出了任意非检控点经仿射变换后输出数据精度的计算公式,并通过数值分析从理论上验证了用四个角框标进行数字影像内定向是最佳误差控制方案。     

Adjustment time of the first baroclinic Rossby wave in the global oceans

1Introduction Planetary waves involve the main processes bywhich perturbation signal in one part of the ocean istransferred to another part.In the1970s,mostof theprevious theoretical studies focus on the local Ekmanpumping and the nondispersive long baroc…