Метод трех направлений     

Karel Kučera 《Studia Geophysica et Geodaetica》1966,10(4):411-421

Summary In [1] the author has put forward a three-direction method, a general way of adjustment of angular observations in incomplete sets by the method of extending into angular combinations, and the definition of mean weightP ^*. In this article the question is dealt with as a whole. In the three-direction methods>3 triangulation directions are measured in direction triplets 123, 234, 345,… …,s12, while in the method of measuring single angles at the station they are measured in angles 12, 23, 34, 45, …,s1. The advantage of transition from angles to direction triplets rests, besides in saving 31% of pointings, above all in certain possibility of elimination of the horizontal refraction, which follows from this. The treatise of the relation between the method of measurement and the refraction is not included into this article, as it would go beyond its scope. The fact that adjusted directions, with the exception of the stations having four directions, are not of equal weight, is proper not only to the three-direction method. The non-equality of weights is even more conspicuous in the method of measuring single angles at the station, and it appears already at the stations having four directions. In author's view the homogeneity of observation elements is more important than the homogeneity of weights from the point of view of adjustment at the station; therefore the direction triplets ought not to exist abreast with the angles in one programme, and especially the number of observations ought to be constant at one station with adjusted direction of homogeneous mean weight in the net. This transition from angles to direction triplets could also provoke a comment that simultaneous visibility of three adjoining directions occurs less often than of two such directions. The author adds to this that nowadays the causes of this phenomenon, following from unsuitable technique, must be eliminated. It is just air limpidity that ought to define the visibility, not unsufficient or everywhere equal intensity of light of reflectors, or too long sides of the triangulation net. Recent approach to this problem requires simultaneous visibility of all directions during most of the days of observation. In connection with the out-of=date technique, the methods of angular observation often have one unfavourable character: they are the cause of the accumulation of observations of “always visible” directions. The supposed merit of angles thus turns into their imperfection.

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Адрес: Politickych vězňů 12, Praha 1-Nové Město  相似文献   

A simple theoretical interpretation of the cloud system in a dying cyclone from the aspect of the boucher-newcomb model     

Pavla Hlachová  Vojtěch Vítek 《Studia Geophysica et Geodaetica》1966,10(4):481-483

Резюме С помощью принятия простых кинематических предположений и на основании ω—уравнения выла определена конфигурация полос облаков в полностью окклюдированном циклоне без фронтов. Облачная система определяется полем скрытой теплоты, выделяемой в процессах конденсации. Полосы облаков теоретически представляют собой в основном листы синусоидальной спирали.

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Address: Boční II, Praha 4-Spořilov.  相似文献   

The system water-glycerol-gelatine as a medium for three-dimensional seismic models     

Ludvík Waniek 《Studia Geophysica et Geodaetica》1966,10(3):273-279

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河口环流和盐水入侵Ⅱ--径流量和海平面上升的影响   总被引：1，自引：0，他引：1  

胡松  朱建荣  傅得健  吴辉 《中国海洋大学学报(自然科学版)》2003,33(3):337-342

本文利用本序列上篇论文建立的理想河口数值模式,研究径流量和海平面上升对河口环流和盐水入侵的影响.在径流量增大的情况下,口门内表层向海的流速增大,底层向陆的密度流减弱,滞流点下移.口门外侧向口门的密度流增大,上升流趋于增强.口门内盐水入侵减弱,口外盐度减小、冲淡水扩展范围增大.在口门上游北岸底层盐度下降明显,口门处南岸表层盐度下降明显.径流量变化对盐水入侵影响十分巨大.在海平面上升的情况下,拦门沙区域向陆的密度流增强,滞流点上移,表层向海的流动增大.口门内盐水入侵增强,口外盐度增大,冲淡水扩展范围减小.海平面上升对盐水入侵影响十分明显,北岸底层盐度增大尤为特出.  相似文献   

基于EOF分析对南海西北海域水体光谱特性的研究   总被引：1，自引：0，他引：1  

付东洋  黄宇业  刘大召  廖珊  余果  张小龙 《海洋学报(英文版)》2020,39(7):107-114

This study presents an analysis of the spectral characteristics of remote sensing reflectance(R_(rs)) in northwestern South China Sea based on the in situ optical and water quality data for August 2018.R_(rs)was initially divided into four classes,classes A to D,using the max-classification algorithm,and the spectral properties of whole R_(rs) were characterized using the empirical orthogonal function(EOF) analysis.Subsequently,the dominant factors in each EOF mode were determined.The results indicated that more than 95% of the variances of R_(rs) are partly driven by the back-scattering characteristics of the suspended matter.The initial two EOF modes were well correlated with the total suspended matter and back-scattering coefficient.Furthermore,the first EOF modes of the four classes of R_(rs)(A-D R_(rs)-EOF_1) significantly contributed to the total variances of each R_(rs) class.In addition,the correlation coefficients between the amplitude factors of class A-D R_(rs)-EOF_1 and the variances of the relevant water quality and optical parameters were better than those of the unclassified ones.The spectral shape of class AR_(rs)-EOF_1 was governed by the absorption characteristic of chlorophyll a and colored dissolved organic matter(CDOM).The spectral shape of class B R_(rs)-EOF_1 was governed by the absorption characteristic of CDOM since it exhibited a high correlation with the absorption coefficient of CDOM(a_g(λ)),whereas the spectral shape of class C R_(rs)-EOF_1 was governed by the back-scattering characteristics but not affected by the suspended matter.The spectral shape of class D R_(rs)-EOF_1 exhibited a relatively good correlation with all the water quality parameters,which played a significant role in deciding its spectral shape.  相似文献   

First results from the North Iceland experiment     

C. Riedel  A. Tryggvason  B. Brandsdottír  T. Dahm  R. Stéfansson  M. Hensch  R. Böðvarsson  K. S. Vogfjord  S. Jakobsdottír  T. Eken  R. Herber  J. Holmjarn  M. Schnese  M. Thölen  B. Hofmann  B. Sigurdsson  S. Winter 《Marine Geophysical Researches》2006,27(4):267-281

Between June 2004 and September 2004 a temporary seismic network was installed on the northern insular shelf of Iceland and onshore in north Iceland. The seismic setup aimed at resolving the subsurface structure and, thus, the geodynamical transition from Icelandic crust to typical oceanic crust along Kolbeinsey Ridge. The experiment recorded about 1,000 earthquakes. The region encloses the Tjörnes Fracture Zone containing the Husavik–Flatey strike-slip fault and the extensional seismic Grimsey Lineament. Most of the seismicity occurs in swarms offshore. Preliminary results reveal typical mid-ocean crust north of Grimsey and a heterogeneous structure with major velocity anomalies along the seismic lineaments and north–south trending subsurface features. Complementary bathymetric mapping highlight numerous extrusion features along the Grimsey Lineament and Kolbeinsey Ridge. The seismic dataset promises to deliver new insights into the tectonic framework for earthquakes in an extensional transform zone along the global mid-ocean ridge system.  相似文献   

The second order spectrum of two-dimensional random waves     

Ding Pingxing  Sun Fu  Yu Zhouwen 《海洋学报(英文版)》1994,13(1):23-29

Ｔｈｅｓｅｃｏｎｄｏｒｄｅｒｓｐｅｃｔｒｕｍｏｆｔｗｏ－ｄｉｍｅｎｓｉｏｎａｌｒａｎｄｏｍｗａｖｅｓ￥ＤｉｎｇＰｉｎｇｘｉｎｇ；ＳｕｎＦｕａｎｄＹｕＺｈｏｕｗｅｎ（ＲｅｃｅｉｖｅｄＪａｎｕａｒｙ１５，１９９３；ａｃｃｅｐｔｅｄＭａｙ３１，１９９３）Ａ...  相似文献   

渤海、黄海、东海水温垂直结构统计特征分析     

蓝淑芳  顾传宬  傅秉照 《海洋科学集刊》1985,(25):11-26

渤海、黄海与东海的水温垂直结构呈现陆架浅海特有的水文特征，其分布与变化甚为复杂。几十年来，虽然中外海洋学家曾对这些海区水文要素的分布及其变异作过大量研究，但是，关于水温垂直结构各特征值较系统的分析研究则始于六十年代初期，毛汉礼等根据一年观测资料(1958-1959)作了较全面的阐述。但是这些资料多数是用颠倒温度表观测，少数为深度温度计(BT)观测；并且研究海区限千124°E以西。本文试图分析研究近年来渤海、黄海与东海水温垂直结构各特征值的统计特性；研究海区有了较大的扩展：黄海至124°30''E；东海至127°E。 文中引用国家海洋局1975一1980年间BT观测资料，共计166个观测站，累积约七千余个BT片资料。  相似文献   

黄、渤海海岸风沙地貌类型及其分布规律和发育模式   总被引：24，自引：0，他引：24  

傅命佐  徐孝诗  徐小薇 《海洋与湖沼》1997,28(1):56-65

于１９９０－１９９４年，对黄，渤海海岸风沙地貌，风沙沉积，风沙灾害和土地沙漠化现象进行详细的外业调查，测量和填图，在此基础上，利用ＧＩＳ技术原理，对海岸岗沙地貌进行系统的分类研究，对海岸风沙地貌分布规律和发育模式进行较深入的探讨，结果表明，研究区风沙地貌，风沙灾害和土地沙漠化现象主要分布在冬，春季气候干旱，风力强而持久，砂源丰富的渤海海岸和山东半岛半岸的砂质海岸地区，海岸沙丘和风成砂地总面积达７０  相似文献   

海洋生物-光学算法研究──南黄海叶绿素浓度的估算     

傅克忖  曾宪模  李宝华  曾晓起  荒川久幸 《海洋与湖沼》1997,28(3):238-244

根据１９９５年９月中日合作南黄海现场观测资料，对南黄海生物－光学算法进行研究。首先对南黄海现场多光谱反射比数据进行因子分析，解反射比协方差矩阵的特征问题；解出特征值和对应的特征向量，求出主因子，然后建立叶绿素α对主因子的多元线性回归方程，并对算法进行回报和预报检验。计算结果表明，该算法具有较高精度，同时也显示出天气条件对估算精度产生较大影响。  相似文献