Ellipsoidal vertical deflections and ellipsoidal gravity disturbance: Case studies

First, we present three different definitions of the vertical which relate to (i) astronomical longitude and astronomical latitude as spherical coordinates in gravity space, (ii) Gauss surface normal coordinates (also called geodetic coordinates) of type ellipsoidal longitude and ellipsoidal latitude and (iii) Jacobi ellipsoidal coordinates of type spheroidal longitude and spheroidal latitude in geometry space. Up to terms of second order those vertical deflections agree to each other. Vertical deflections and gravity disturbances relate to a reference gravity potential. In order to refer the horizontal and vertical components of the disturbing gravity field to a reference gravity field, which is physically meaningful, we have chosen the Somigliana-Pizzetti gravity potential as well as its gradient. Second, we give a new closed-form representation of Somigliana-Pizzetti gravity, accurate to the sub Nano Gal level. Third, we represent the gravitational disturbing potential in terms of Jacobi ellipsoidal harmonics. As soon as we take reference to a normal potential of Somigliana-Pizzetti type, the ellipsoidal harmonics of degree/order (0,0), (1,0), (1, − 1), (1,1) and (2,0) are eliminated from the gravitational disturbing potential. Fourth, we compute in all detail the gradient of the gravitational disturbing potential, in particular in orthonormal ellipsoidal vector harmonics. Proper weighting functions for orthonormality on the International Reference Ellipsoid are constructed and tabulated. In this way, we finally arrive at an ellipsoidal harmonic representation of vertical deflections and gravity disturbances. Fifth, for an ellipsoidal harmonic Gravity Earth Model (SEGEN: http://www.uni-stuttgart.de/gi/research/paper/coefficients/coefficients.zip) up to degree/order 360/360 we compute the global maps of ellipsoidal vertical deflections and ellipsoidal gravity disturbances which transfer a great amount of geophysical information in a properly chosen equiareal ellipsoidal map projection.     

我国两种蒸发观测资料的对比分析

通过１９８０年以后的Ｅ－６０１型蒸发资料与相同时期的２０ｃｍ小型蒸发资料的比较,分析了两种蒸发资料的特点,给出了两者的折算系数、相关系数、离差系数,建立了利用小型蒸发资料计算大型蒸发资料的订正公式     

Estimation of dynamic ocean topography in the Gulf Stream area using the Hotine formula and altimetry data

Two modifications of the Hotine formula using the truncation theory and marine gravity disturbances with altimetry data are developed and used to compute a marine gravimetric geoid in the Gulf Stream area. The purpose of the geoid computation from marine gravity information is to derive the absolute dynamic ocean topography based on the best estimate of the mean surface height from recent altimetry missions such as Geosat, ERS-1, and Topex. This paper also tries to overcome difficulties of using Fast Fourier Transformation (FFT) techniques to the geoid computation when the Hotine kernel is modified according to the truncation theory. The derived absolute dynamic ocean topography is compared with that from global circulation models such as POCM4B and POP96. The RMS difference between altimetry-derived and global circulation model dynamic ocean topography is at the level of 25cm. The corresponding mean difference for POCM4B and POP96 is only a few centimeters. This study also shows that the POP96 model is in slightly better agreement with the results derived from the Hotine formula and altimetry data than POCM4B in the Gulf Stream area. In addition, Hotine formula with modification (II) gives the better agreement with the results from the two global circulation models than the other techniques discussed in this paper. Received: 10 October 1996 / Accepted: 16 January 1998     

高强混凝土桩中坍落度的选取与应用

叙述了高强混凝土在桩基工程中的实际应用,提出了桩基混凝土试配当中与一般混凝土试配的不同之处及试配的方法与具体应用。     

A Note on Extension Variances in IR2

Matheron (1971) proposed an approximation of the extension variance in IR. We propose in this note an extension of this formula in IR ² , based on a MacLaurin formula. Its application is shown in an example, the estimation of the maximum depressional storage of a soil surface.     

热压薄壁金刚石钻头的设计制造与应用

对薄壁金刚石钻头的结构、钢体、加工工艺和规程进行了介绍与分析,并对薄壁金刚石钻头胎体作了不同配方的筛选,选出了ＧＷ１和ＧＷ２号配方,在室内和生产试验中取得了较好的效果。     

新矿物（1992.7—1992.12）

本文以表格形式列举了１９９２年７月至１９９２年１２月经《国际矿物学协会（ＩＩＭＡ）新矿物与矿物命名委员会（ＣＮＭＭＮ）》批准并在各国矿物学杂志上发表的５０个新矿物的中文英文名称、化学式及其他数据。数据依次为：矿物的晶系、空间群、晶胞参数、主要粉晶数据（Ｉ、ｈｋｌ）、物理性质（晶形、颜色、条痕、光泽、解理、发光、硬度、密度等）、光学性质（一、二轴晶、正、负光性,折光率,反射率,双反射,２Ｖ,色散,吸     

倾角函数递推公式的误差传递分析

在倾角函数递推关系这个题目上,一些研究者做过工作,如Challe,A(1969),R.H.Googing(1971),J.A.Campbell(1972),G.E.O.Giacaglia(1976)和童付(1979)。最好的结果是由童付获得的,递推关系仅由二个或三个相邻的函数来表达。然而,当倾角较小时,童付的公式存在严重的计算误差传递。本文导出了一个分析公式来估计此种计算误差传递,并在分析计算误差传递机制的基础上,指出可避免计算误差传递的途径,导出的分析公式见文中第(9)式。     

叶尔羌河流域潜水蒸发规律试验分析

本文根据新疆叶尔羌河流域地下水均衡场的潜水蒸发试验资料,探讨了潜水蒸发的影响因素,对潜水蒸发量进行了公式拟合。结果表明,指数型公式,阿维里扬诺夫公式和清华公式比较适合于该地区潜水蒸发量的估算,幂函数型公式的拟合结果较差,简化的指数型有一定的适用范围。     

面平均雨量的积分计算

利用二重积分表示流域降雨总量。目前计算面平均雨量的三种方法,均可视为对区域进行某种划分及观测点做为特殊点时用二重积分定义进行的近似计算。对区域降雨量函数进行了探讨。