Variability of surface circulation in the South China Sea from satellite altimeter data

11-year satellite altimeter sea surface height （SSH） anomaly data from January 1993 to December 2003 are used to present the dominant spatial patterns and temporal variations of the South China Sea （SCS） surface circulation through Empirical Orthogonal Function （EOF） analysis. The first three EOF modes show the obvious seasonal variations of SSH in the SCS. EOF mode one is generally characterized by a basin-wide circulation. Mode two describes the double-cell basin scale circulation structure. The two cells were located off west of the Luzon Island and southeast of Vietnam, respectively. EOF mode three presents the mesoscale eddy structure in the western SCS, which develops into a strong cyclonic eddy rapidly from July to September. EOF mode one and mode three are also embedded with interannual signals, indicating that the SCS surface circulation variation is influenced by El Nino events prominently. The strong El Nino of 1997/98 obviously changed the SCS circulation structure. This study also shows that there existed a series of mesoscale eddies in the western SCS, and their temporal variation indicates intra-seasonal and interannual signals.     

河北平原旱涝时北太平洋海温演变特征分析

本文对河北平原旱涝与北太平洋海温距平之间关系进行了研究,发现东太平洋赤道区和黑潮区海温异常分布对河北旱涝影响最为显著。基于统计分析结果,本文提出了北太平洋海温异常对河北平原旱涝影响的可能途径。     

山地GPS高程测量方法探索

在分析GPS测高理论的基础上，提出了用建立基础高程面和加入山区重力异常改正的方法，实现山地区域GPS精确测高，并用实例进行了栓核，达到了四等水准测高精度要求。该方法还可减少GPS测高中所需的水准联测工作量。     

基于数学曲面法的GPS水准拟合的研究与实现

GPS在测量领域的应用给传统测量带来了历史性变革,但GPS三维坐标中的Z坐标,即大地高未能在生产实际中发挥应有的作用,使得GPS测量在确定平面坐标之后还要在测站上进行几何水准测量。如何能有效利GPS的高程信息,把大地高转换成正常高,直接为测绘生产服务,实观GPS观测时能同时获得实用的三维坐标,值得研究。针对目前GPS水准高程研究的现状,本文引入数学曲面拟合法,并结合实例分析,总结了该拟合模型的优缺点,并给出了一些合理建议。     

关于液体遇竖直坚固器壁平面时表面高度的奇摄动问题

先从理论上研究了超二次奇摄动Robin问题εy“=h(t,y)f(y’),t∈[0,L],y(0,ε)-py'(0,ε)=A(ε),y(L,ε) qy'(L,ε)=B(ε),然后给出了这一问题解的估计,并证明了解的渐近性．最后,将这一理论用于解决液体遇竖直固器壁平面时,表面高度的问题．     

热带印度洋海面温度与高度的相关性分析

基于海面温度与海面高度异常的月均数据,采用EOF、SVD和功率谱分析等方法,对热带印度洋海面温度与海面高度进行特征分析,研究两者在时空结构上的相关性。利用EOF方法分析出海面温度第二模态与海面高度第一模态的空间结构类似,呈现偶极型。相关分析与功率谱表明,两模态的时间序列存在滞后相关和类似的周期结构。SVD结果显示,第一耦合模态的相关系数达0.7左右,且左右场的空间形态呈现东西反相。这表明,海面高度偶极型与海面温度的单极型和偶极型存在着相关。同时,海面高度指数也表现与偶极子指数类似的结构特征。针对上述诊断分析事实特征,对海面温度和海面高度偶极子形成的物理机制进行了初步分析,总结了前人所做的一些工作,指出其中可能的影响因素。     

Coastal seafloor observatory at Xiaoqushan in the East China Sea

The seafloor observation system is becoming an important infrastructure for marine research because it is transforming oceanic research from temporal investigation to long term observation.The East China Sea coastal seafloor observatory,located between 30°31′44″N,122°15′12″E and 30°31′34″N,122°14′40″E,is constructed near the Xiaoqushan Island outside the Hangzhou Bay on the inner continental shelf of the East China Sea.The observatory is connected by a submarine optical fiber composite power cable that is more than one kilometer long and consists of a special junction box that transmits power and communication signals to different instruments.The special junction box has a variety of waterproof plugs and connects to three different instruments installed in a trawl preventer.The submarine optical fiber composite power cable is landed on the platform by The East China Sea Branch,State Oceanic Administration and the power is continuously supplied by the solar panels and solar battery on the top of the platform.The real time data are directly sent through the cable to the platform and are transmitted by CDMA wireless to the receiver at the State Key Laboratory of Marine Geology of Tongji University.Measurements at the observatory have been taken since April 20,2009 after installation and the results have been interpreted.The characteristics of the near bottom boundary are constrained by a sediment suspension model using portion of the observed data.In particular,discussion is provided on the sea surface height anomaly at Xiaoqushan Island influenced by the tsunami driven by the 2010 Earthquake in Chile.The successful establishment of the coastal seafloor observatory is the first step toward future development of seafloor observation systems in China.It not only accumulates experiences in technology and engineering,but also paves the way for performing important oceanic research using the long term continuous observation platform.     

基于阴影恢复形状的织物表面形态研究

分析了一种新的由阴影恢复形状算法,并提出了实现算法的具体步骤和计算方法.对合成图像进行迭代计算,获得了较为准确的表面高度,并对实际织物图像验证了该算法的可行性.     

平面加工中导向定位面支撑高度对平面加工定位误差大小的影响

针对平面加工中的情况,讨论了平面定位中导向定位面支撑高度对定位误差影响的不同情况,得出了其定位误差大小不仅与导向定位面的支撑高度有关,还与被加工面的大小有关的结论.     

黄渤海风、浪、流等海洋水文要素特征分析

随着我国海洋建设的快速发展,深入了解海洋水文环境特征,为海洋工程等提供保障已迫在眉睫。本文根据日常保障经验,结合相关理论,利用QN（QuikSCAT/NCEP）混合风场、模拟海浪数据等资料,对黄渤海海域的海洋水文特征进行分析,主要分析了该海域的海表风场、海浪场、潮汐潮流、海雾、盐度、SST（海表温度——Sea Surface Temperature）的特征,可为防灾减灾、航海、海洋水文保障、海洋工程、海洋能资源开发利用提供科学依据。     

基于频谱分析的织物粗糙感

传统研究一般通过测试织物表面的几何粗糙度和摩擦性能来预测粗糙感,而认知科学家发现,栅栏粗糙性的辨别取决于表面纹理波动曲线的谐波成分及纹理间距.为深入揭示织物粗糙感的形成机制,基于织物的表面形貌曲线,计算平均粗糙度,统计不同波动高度下的纹理间距,并采用傅里叶方法提取频域内谐波特征,比较分析这些特征值与粗糙感之间的关系.研究表明,织物的粗糙感差异取决于表面波动曲线频域内谐波的最高峰高度,而粗糙感不仅与平均粗糙度有关,也与表面纹理间距有关.     

规则表面形貌的表征

量子点与超晶格等有序结构呈现规则的表面形貌,它们的特性与表征表面粗糙度的参数密切相关.本文说明了如何利用单值周期函数对这些规则表面形貌进行模拟,并分析了其高度分布函数,以及给出了高度分布函数与单值函数导数变化的关系.     

车载GPS检测路面标高

采用水准仪测量对通车后的高速道路路面标高检测不仅相当困难且影响交通,还存在着危险性.为此提出利用装载GPS的车辆,沿车道行驶来检测路面标高,进行路面沉降分析或竣工质量评定.介绍了车载GPS动态检测路面标高的应用实验,并进行了线路数据的计算与分析,探讨了该方法的应用可行性.     

曲面拟合原理在GPS高程测量中的应用

介绍了曲面拟合原理,阐述了用曲面拟合原理进行GPS高程测量的布设原则,提出了提高其测量精度的方法。     

Higher sea surface temperature in the northern South China Sea during the natural warm periods of late Holocene than recent decades

The large-scale syntheses of global mean temperatures in IPCC fourth report suggested that the Northern Hemisphere temperature in the second half of the 20th century was likely the highest in at least the past 1,300 years and the 1990s was likely the warmest decade. However, this remains debated and the controversy is centered on whether temperatures during the recent half century were higher than those during the Medieval Cli- mate Anomaly （MCA, AD 800-1300） and the Roman Warm Period （RWP, BC 200-AD 400）, the most recent two natural warm periods of the late Holocene. Here the high resolution sea surface temperatures （SSTs） of two time windows around AD 990 （±40） and AD 50 （±40）, which located in the MCA and RWP respectively, were reconstructed by the Sr/Ca ratio and 6180 of Tradacna gigas shells from the northern South China Sea. The resultssuggested that the mean SSTs around AD 990 （±40） and AD 50 （＋40） were 28.1 ℃ and 28.7 ℃, 0.8 ℃ and 1.4 ℃ higher than that during AD 199±2005, respectively. These records, together with the tree ring, lake sediment and literature records from the eastern China and northwest China, imply that the temperatures in recent decades do not seem to exceed the natural changes in MCA, at least in eastern Asia from northwest China to northern SCS.