静态精密单点定位中对流层延迟估计     

李凯锋  欧阳永忠  陆秀平  吴太旗  任来平 《海洋测绘》2011,31(6):12-15

首先介绍了三种对流层误差改正模型,然后把模型改正值作为先验值,将天顶延迟的剩余误差作为待定参数,分别用卡尔曼滤波和最小二乘两种估计方法计算对流层的残余量;实验证明Saastamoinen模型优于后两种模型,并利用实测气象参数计算对流层延迟,结果表明标准模型与实测气象参数对静态精密单点定位中对流层延迟量的计算结果影响不大...  相似文献   

Stream-coordinate structure of oceanic jets based on merged altimeter data     

孙澈  张林林  闫晓梅 《中国海洋湖沼学报》2011,29(1):1-9

The jet structure of the Southern Ocean front south of Australia is studied in stream-coordinate with a new altimeter product—Absolute Dynamic Topography (ADT) from AVISO. The accuracy of the ADT data is validated with the mooring data from a two-year subantarctic-front experiment. It is demonstrated that the ADT is consistent with in-situ measurements and captures the meso-scale activity of the Antarctic Circumpolar Current (ACC). Stream-coordinate analysis of ADT surface geostrophic flows finds that ACC jets exhibit large spatio-temporal variability and do not correspond to particular streamfunction values. In the circumpolar scope ACC jets display a transient fragmented pattern controlled by topographic features. The poleward shift of jet in streamfunction space, as revealed by a streamwise correlation method, indicates the presence of meridional fluxes of zonal momentum. Such cross-stream eddy fluxes concentrate the broad ACC baroclinic flow into narrow jets. Combined with a recent discovery of gravest empirical mode (GEM) in the thermohaline fields, the study clarifies the interrelationship among front, jet and streamfunction in the Southern Ocean.  相似文献   

SHADOWS合成孔径声纳系统及性能测试     

牟健  贺惠忠  姜峰 《中国海洋大学学报(自然科学版)》2011,(Z2):159-163

与传统的侧扫声纳相比,合成孔径声纳系统具有全覆盖无遗漏扫测,测量范围大、速度快,图像分辨率高等优点。本文介绍我国引进第一套SHADOWS合成孔径声纳系统的技术性能,分析SHADOWS合成孔径声纳系统性能测试情况及实际测量中的应用价值,提出了存在的问题及其对策。  相似文献   

Effect of reclamation time and land use on soil properties in Changjiang River Estuary,China   总被引：4，自引：1，他引：3  

ülo MANDER 《中国地理科学(英文版)》2011,21(4):403-416

The objective of this study is to analyze soil physical and chemical properties,soil comprehensive functions and impact factors after different years of reclamation.Based on the survey data taken from 216 soil sampling points in the Fengxian Reclamation Area of the Changjiang (Yangtze) River Estuary,China in April 2009 and remotely sensed TM data in 2006,while by virtue of multivariate analysis of variance (MANOVA),geo-statistical analysis (GA),prin-cipal component analysis (PCA) and canonical correspondence analysis (CCA),it was concluded that:1) With the in-crease in reclamation time,soil moisture,soil salinity,soil electric conductivity and soil particle size tended to decline,yet soil organic matter tended to increase.Soil available phosphorous tended to increase in the early reclamation period,yet it tended to decline after about 49 years of reclamation.Soil nitrate nitrogen,soil ammonia nitrogen and pH changed slightly in different reclamation years.Soil physical and chemical properties reached a steady state after about 30 years of reclamation.2) According to the results of PCA analysis,the weighted value (0.97 in total) that represents soil nutrient factors (soil nitrate nitrogen,soil organic matter,soil available phosphorous,soil ammonia nitrogen,pH and soil particle size) were higher than the weighted value (0.48 in total) of soil limiting factors (soil salinity,soil elec-tric conductivity and soil moisture).The higher the F value is,the better the soil quality is.3) Different land use types play different roles in the soil function maturity process,with farmlands providing the best contribution.4) Soil physi-cal and chemical properties in the reclamation area were mainly influenced by reclamation time,and then by land use types.The correlation (0.1905) of the composite index of soil function (F) with reclamation time was greater than that with land use types (-0.1161).  相似文献   

变值配置函数空间整体编码族的2维对称性     

郑智捷 《成都信息工程学院学报》2011,(6):579-589

研究0-1多元变量的逻辑函数及其整体配置函数空间变值编码表示特性。根据对称特性,系统地定义一批整体编码结构:邵雍-Leibniz码、广义码、文王码、伏羲码和共轭码。展示变值向量配置函数空间规模以及函数群集的状态空间组织结构。对各类编码系列的可区分数目,给出计算公式。2维变值展示框架展现在变值配置函数空间中不同编码族具有的内蕴对称特性。分层结构编码配置函数空间和2维展现描述体系,为基于东方逻辑传统的现代逻辑架构:变值逻辑体系,利用高维分析工具探讨0-1序列非线性超复杂逻辑变换开辟道路。  相似文献   

基于图像退化模型的天气现象识别     

宋晓建  杨玲 《成都信息工程学院学报》2011,(4):132-136

在不同的天气条件下,由于气溶胶对光波的散射作用,通过成像系统获得的图像都会有一定程度的退化。利用图像的退化模型可以获取与天气现象相关的参量,从而达到识别天气的目的。对不同天气条件下得到的同一场景图进行研究,运用多垂线检测法,检测出不同天气条件下直线模糊边缘上的灰度值,采用signloid函数拟合出刃边函数,进而求出线扩散函数。通过分析线扩散函数的变化规律,总结出其与天气现象之间的紧密联系。测试结果表明,应用该方法对于晴天、薄雾、雨、霾、沙尘暴等天气现象具有一定的判别效果。  相似文献   

常见小波的尺度进制求解算法与程序     

黄苹  袁晓 《成都信息工程学院学报》2011,(4):144-148

基于小波变换的稳定性函数来研究尺度进制的算法。用母波的频谱函数来构造出尺度进制为任意进制时的稳定性函数,根据稳定性函数计算小波框架的边界、紧致度和收敛因子,最后由框架参数值进一步计算得到尺度进制范围。结果表明,此范围有效地缓解了小波变换的稳定性和冗余性之间的矛盾。  相似文献   

Perceptions of Climate Change and Adaptation Responses in a Local Community: the Barwon Estuary Complex,Victoria     

Jaclyne Scally 《The Australian geographer》2011,42(4):387-401

The climate change focus in Australia has shifted from mitigation to adaptation with an emphasis on place-specific case studies. The Barwon Estuary Complex (BEC) on the Bellarine Peninsula, central Victoria, was the focus of this place-specific study in which 37 local stakeholders were consulted through a series of semi-structured interviews on the impacts of climate change on their coastal community. Overall there was uniformity in stakeholder perceptions of the climate change impacts and vulnerabilities pertaining to the BEC. In contrast, discussion on adaptation drew a diversity of responses. While 53 per cent of stakeholders indicated a need to limit the use of hard structures, and rather plan around a changing estuarine environment, opinion amongst the community group was divided. Some believed ‘retreat is the only option’ whilst others felt ‘there won't be much leaving’. The present level of confusion around adaptation highlights the imperative of commencing discussions now to allow sufficient time to develop strategies which are both environmentally and socially responsible. This is important as ultimately it will be the community that will determine whether adaptation strategies are adopted or met with resistance.  相似文献   

东江流域枯水期最长连续无降水日数的变化特征   总被引：3，自引：0，他引：3  

王兆礼  覃杰香  陈晓宏 《地理研究》2011,30(9):1693-1701

利用1956-2008年东江流域各降雨站点逐日降雨资料,建立枯水期最长连续无降水日数时间序列（LCDD）,采用经验模态分解（EMD）方法分析该序列的多尺度振荡变化及趋势变化,应用Mann-Kendall法识别突变点,采用R／S分析方法探讨变化趋势的持续性特征,并初步分析LCDD变化的可能原因。结果表明：近53年来,最长...  相似文献   

用于可重构机床控制系统的电力线通信技术     

杨东升  郇极  Stefan Schmitz 《地理研究》2011,37(9)

介绍了可重构机床对通信系统的要求,提出了一种基于宽带电力线通信（PLC,PowerLine Communication）技术的新型通信系统．通过对机床电力线的信道特性和噪声频谱的分析与测量,选定了通信系统的载波频率和带宽等参数．为了对抗电力线信道的多径效应,提高频谱利用率,实现可靠高效的数据传输,采用正交频分复用技术（OFDM,Orthogonal Frequency Division Multiplex）作为调制解调方式．开发了PLC调制解调器,定义了物理层帧结构．最后以机床主轴伺服系统为例对该通信系统进行了实验验证．实验结果表明,该系统实现了有效数据传输率10Mbit／s,误比特率（BER,Bit Error Rate）小于10^-8的高效数据传输．  相似文献