Generalised observations of wave characteristics on near‐horizontal shore platforms: Synthesis of six case studies from the North Island,New Zealand          下载免费PDF全文

Hiroki Ogawa  Mark E. Dickson  Paul S. Kench 《New Zealand geographer》2016,72(2):107-121

Most field studies of wave processes on shore platforms in front of eroding cliffs focus on a single site, revealing aspects of wave dynamics at that location. Here, we analyse data from six platforms around northeastern New Zealand and describe the fundamental control of shore platform width, gradient and elevation on wave processes, including greater attenuation of short‐period waves at lower tidal stages and increases in longer period wave energy towards the cliff toe. These data suggest that empirical formulae developed from coral‐reef environments provide better predictions of wave height on platforms than formulae currently used in shore platform models.  相似文献   

基于抗差估计的实时单站GPS同震速度获取方法     

鲁洋为  王振杰 《测绘工程》2016,(12):49-54

基于实时单站GPS载波相位历元差分测速模型,引入抗差最小二乘估计,并根据IGGⅢ方案选择合适的等价权因子来削弱小周跳和粗差对结果的影响,并采用一组静态数据和2011年日本"3.11"地震期间MIZU站的高频数据对算法进行测试。结果表明,在含有小周跳和粗差的情况下,抗差最小二乘估计能够明显改善解算速度,可以实时获取测站毫米级的同震速度。  相似文献   

随机误差对七参数转换模型的影响分析     

王建强  张飞 《测绘科学》2016,41(9):20-24

针对在七参数坐标转换过程中,控制点本身含有的各种误差会对坐标转换的结果产生影响的问题,该文探讨了随机误差对七参数转换模型的影响:以七参数坐标转换模型为研究对象,模拟不同尺度范围的空间直角坐标,给定七参数数值求解另一组空间直角坐标,然后加入不同幅度的随机误差,利用最小二乘准则求解参数,从数值角度分析随机误差对七参数数值以及坐标转换结果的影响。实验结果显示,大范围的七参数模型解算的稳定性优于小范围的模型解算,以及X、Y、Z方向某一方向上的误差对另两个方向的解算结果影响较小。  相似文献   

Accuracy of kinematic wave and diffusion wave approximations for space-independent flows on infiltrating surfaces with lateral inflow neglected in the momentum equation     

V. P. Singh 《水文研究》1995,9(7):783-796

Error equations for the kinematic wave and diffusion wave approximations with lateral inflow neglected in the momentum equation are derived under simplified conditions for space-independent flows. These equations specify error as a function of time in the flow hydrograph. The kinematic wave, diffusion wave and dynamic wave solutions are parameterized through a dimensionless parameter γ which is dependent on the initial conditions. This parameter reflects the effect of initial flow depth, channel-bed slope, lateral inflow, infiltration and channel roughness when the initial condition is non-vanishing; it reflects the effect of bed slope, channel roughness and acceleration due to gravity when the initial condition is vanishing. The error equations are found to be the Riccati equation. The structure of the error equations in the case when the momentum equation neglects lateral inflow is different from that when the lateral inflow is included.  相似文献   

低纬子午环仪器误差的测定及其处理方法     

胡玉平 《天文研究与技术》1997,(1)

仪器误差的精确测定和消除对于提高子午环的观测精度有着至关重要的意义。本文简单介绍了低纬子午环的观测原理和仪器结构，系统地探讨了它的各种仪器误差的来源、测定和处理方法。为了进一步完善采用组合固定角距法测定对径改正的方法，在第三章，研究了提高对径改正测量精度的方法，重新推导了对径改正的计算公式，并就某些具体的条件，对其进行了模拟验证，得到了较为满意的结果  相似文献   

COMPARISON OF MEASUREMENT METHODS BASED ON A MODEL FOR THE ERROR STRUCTURE     

GRAN NILSSON 《地理学报(英文版)》1991,(6)

Comparison of methods is a technique often used for investigation of systematic errors of measurementmethods.As concerns the design and analysis of such comparisons,much variety of opinion and practiceexists.In one approach a few specimens are measured several times by different operators in differentlaboratories(reproducibility conditions)and in another approach several specimens are measured on oneor a few occasions by one operator in the same laboratory(repeatability conditions).In this paper amodel for the error structure of measurements is formulated and it is emphasized that one has todistinguish between two types of systematic errors:the first type depends only on the level of themeasured quantity and the second type is specific for the separate specimens.On the basis of this modelthe information which can be obtained from the different designs of method comparisons is discussed.A new approach for the analysis of method comparisons with many specimens is also proposed.  相似文献   

用拟准检定法和补偿最小二乘估计解算污染半参数模型     

张俊  独知行  杜宁  张显云 《测绘科学》2014,39(10)

现代自动化测绘技术采集的测量数据中系统误差和粗差都在所难免,需要同时考虑系统误差和粗差共存的平差问题.针对污染半参数模型中含有系统误差和观测值受到污染而不严格服从正态分布的情形,文章探讨了用拟准检定法抵御粗差,用补偿最小二乘法分离系统误差.算例表明:用拟准检定法对粗差进行定位定值并对观测误差进行修正后,再利用补偿最小二乘法解算半参数模型,可以得到较好的结果.  相似文献   

稳健估计方法提高数据处理精度     

石越 《北京测绘》2014,(5):134-135

介绍了近代平差理论的稳健估计方法,编制稳健估计方法的程序,并通过实例验证,与最小二乘估计进行比较,表明稳健估计在水准网粗差探测和平差计算中优于最小二乘估计方法,并且能够定位粗差,从而进行消除或者减弱,得到较为干净的观测值。因此,稳健估计方法应用于测量平差具有一定的抵抗粗差的能力,从而可以提高数据处理的精度。  相似文献   

云南元阳大坪金矿矿床成因讨论     

刘玉昆 《云南地质》2013,(4):386-388

金矿位于哀牢山构造变质岩带、金（贵金属）成矿带南部西侧,含金石英脉分布于小新街断裂两侧的次级构造裂隙中,矿脉严格受次级压扭性断裂控制.  相似文献   

云南维西娃渣铁铅锌多金属矿床     

黄跃  王炳华  罗光明  胡清华 《云南地质》2013,(4):429-432,442

矿床属与中三叠统中酸性火山岩有关的喷流型（或火山沉积改造型）铁铅锌多金属矿,并受地层构造双重控制.  相似文献