The role of the Indian Ocean in determining the tropical pacific SST response to radiative forcing in an idealized model

The complexity of the tropical climate system demands the development of a hierarchy of models to ensure our understanding of its response to anthropogenic forcing. The response of the tropical Pacific Ocean to radiative forcing has been studied previously with a box model. The model has provided insights into the tropical Pacific climate change that are otherwise not easily attainable. But that model only encompasses the tropical Pacific region. Recent studies have also shown that the Indian Ocean (IO) may be important in the response of the Pacific Walker circulation to radiative forcing, raising the need to expand the model to take into account the role of IO. This study presents the results concerning the tropical Pacific response to radiative forcing from an expanded-box model that includes the tropical IO, which influences the tropical Pacific through an inter-basin SST gradient.The three-box model predicts an enhanced zonal SST gradient in tropical Pacific in response to the increased radiative forcing, similar to the previous two-box model. It is further noted that in the three-box model, a warmer IO relative to the Pacific enhances Pacific easterlies and subsequently strengthens the equatorial ocean circulation. Because of this ocean dynamical cooling, the warming response in the Pacific is effectively reduced in the three-box model that includes the role of IO compared with that in the two-box model. The role of the IO warming trend in enhancing the Pacific trade winds is confirmed using an atmospheric general circulation model experiment. These results may help to fully explain the relatively small observed warming trend in the tropical Pacific compared to that in the tropical IO evident in 20th century SST reconstructions.     

The model of a flat (Euclidean) expansive homogeneous and isotropic relativistic Universe in the light of the Wilkinson Microwave Anisotropy Probe (WMAP) observations

The Wilkinson Microwave Anisotropy Probe (WMAP) confirmed the model of a flat (Euclidean) expansive homogeneous and isotropic relativistic universe with the total zero mass (energy), which describes the properties of our observed expansive homogeneous and isotropic relativistic Universe in the first (linear, Newtonian or classical-mechanical) approximation.     

基于GIS和单元簇的模糊逻辑推理及其在区域矿产预测中的应用

论述了 GIS支持下的一种基于“单元簇”概念和模糊逻辑推理的多元地学信息综合分析方法及其在区域矿产预测中的应用。针对以往矿产定量预测中的单元划分方法对空间信息利用不足的问题 ,用单元的空间组合 (“单元簇”)代替单元作为定量类比的基本单位 ,从而能较充分地利用地质变量的局部空间结构信息 ;将单元作为 GIS区图元 ,利用 GIS空间分析功能实现对单元及单元簇的管理和操作 ;建立两个层次即变量对单元和组成单元对单元簇的模糊推理规则 ,经两次模糊推理计算出所有未知单元的找矿有利度 ,为进一步圈定找矿远景区提供了基础 ,并以新疆康古尔塔格地区金矿预测实例说明了其应用效果     

GPS辅助光束法区域网平差—太原试验场GPS航摄飞行试验结果

本文简要介绍了ＧＰＳ辅助光束法区域网平差的基本原理和方法，详细讨论了太原航摄机动态试验场实际ＧＰＳ航摄飞行试验的结果。利用联合平差程序ＷｕＣＡＰＳ系统对试验区进行ＧＰＳ辅助光束法区域网平差，用分米级精度的ＧＰＳ摄站坐标获得了实地上平面为±７．９ｃｍ、高程为±１８．１ｃｍ的加密精度，充分显示了动态ＧＰＳ定位技术在航空遥感定位中的广阔应用前景。     

生物多样性模型的理论分析

本文首先概括了50年代以来公开发表的27个生物多样性模型和有关专家对其中大多数模型的批评。在此基础上,以使用最广泛的Shannon模型为例,剖析了大多数生物多样性模型不能被成功应用于实践研究的根源所在;以基于分维几何学的物种多样性模型为例,从理论上分析了这种综合生物多样性模型的完备性。并以位于中国东北样带(NECT)东部的温带针阔叶混交林地区的8个样地作为案例,对比分析了Shannon模型大样本要求的局限性和基于分维几何学的综合生物多样性模型的实用性。     

沙漠历史地理学的几个理论问题--以我国河西走廊历史上的沙漠化研究为例

干旱地区的沙漠化主要发生在内陆河流下游,沙漠化过程的途径主要有就地起沙、风蚀绿洲、流沙入侵、洪积物掩埋绿洲４种,前两者最重要。由于绿洲水资源的移动和重新分布而导致绿洲的转移过程,并不一定意味着绿洲的缩小或消失;只要大的气候环流形势和流域的总水量无大变化,则其绿洲总面积就不致发生大的改观,沙漠化土地在一定条件下是可以逆转的。     

Ray parameters of diffracted long period P and S waves and the velocities at the base of the mantle

The derivation of P and S velocities at the core-mantle boundary (CMB) from long-period diffracted waves by the use of the simple ray-theoretical formulav _CMB=r _c /p (v _CMB=velocity at the CMB;r _c =core radius;p=ray parameter) yields apparent velocity values which differ from the true velocities. Using a dominant period of about 20 sec for calculating theoretical seismograms, we found a linear relation between the apparent velocity and the average velocity in a transition zone at the base of the mantle with fixed velocity on top.The ray parameters determined from long-period earthquake data are found to be 4.540±0.035 and 8.427±0.072 sec/deg for P_diff and S_diff, respectively. These values yield apparent velocities of 13.378±0.103 for P and 7.207±0.062 km/sec for S waves. By means of the theoretical relation between apparent and average velocity and under the assumption of linear variation of velocity with depth, one can invert the apparent velocities into true CMB velocities of 13.736±0.170 and 7.320±0.124 km/sec. These results imply positive velocity gradients at the base of the mantle and hence no significant departures from adiabaticity and homogeneity.Contribution No. 211 of the Geophysical Institute, University of Karlsruhe.     

Atmospheric electrode effect: Approximate theory and wintertime observations

Summary The steady-state equations of the atmospheric electrode effect, i.e. the depletion of negative ions near the ground, are solved analytically in an approximate way. The presence of monodisperse aerosol is included. The method is based on the assumption that the positive ion density remains nearly, although not strictly, constant with height. The results show explicitly the effect of various parameters on the electrode layer. In particular, the height is directly proportional to the current density, and it depends on aerosol density only through the influence of the aerosol on the current density. The results are used to give a tentative explanation, in terms of the electrode effect, to an observed wintertime difference of the two polar conductivities.     

用改进的增量方法计算硫化物中硫的同位素分馏系数

增量方法已成功地应用到硅酸盐矿物、金属氧化物、碳酸盐矿物和硫酸盐矿物氧同位素分馏系数的计算中。本文在对硫化物晶体结构与矿物学特点分析的基础上,通过详细分析前人对硅酸盐矿物和金属氧化物中氧同位素分馏的增量计算方法,将氧化物和硫化物的晶体特征加以对比,提出了计算硫化物中硫同位素分馏的增量计算方法。修正的增量方法根据硫化物的晶体化学结构特征,引入了一个重要的参数,即Madelung常数,用于指示不同结构的硫化物对~(34)S的富集能力。本文利用这一修正的增量方法计算出了0℃到1000℃温度范围内,磁黄铁矿、方铅矿、闪锌矿、黄铜矿、硫镉矿的10~3Inβ和它们之间的分馏系数10~3Inα。并给出这五种矿物间的~(34)S富集顺序：磁黄铁矿＞硫镉矿＞闪锌矿＞黄铜矿＞方铅矿。与前人的实验结果对比表明,本次计算结果与实验结果基本吻合。同时,增量计算方法成功地再现了任意硫化物中~(32)S、~(33)S、~(34)S和~(36)S这四种同位素之间确实存在一定的分馏比例关系。这说明尽管增量方法存在一定的局限性,但将其扩展到硫化物间硫同位素分馏的理论计算是可行的。     

煤层厚度变化时地震槽波理论频散曲线计算方法及频散特征分析

槽波地震勘探利用槽波的频散特性反演煤层的结构特征,故理论频散曲线的计算是一个重要方面.使用水平层状模型假设下的面波频散曲线计算方法能够计算煤层厚度恒定模型地震槽波频散曲线;但当煤层厚度变化时该方法不再适用.基于前人水平层状均匀介质模型的面波理论频散曲线计算方法,对于含煤三层模型,本文发展了煤层厚度变化情况下的地震槽波理论频散曲线计算方法,并使用该方法计算分析了不同厚度函数模型的频散曲线形态特征.研究表明：与稳定厚度煤层相比,煤层厚度变化使得地震槽波群速度成为与频率及传播射线在水平面投影路径相关的二元函数;射线路径上煤层厚度的变化使得频散曲线在群速度方向上压缩,群速度变化范围变小,且使处于最小值位置的埃里相群速度增大;而煤层厚度的线性变化模型频散曲线只与射线首、尾处的煤层厚度有关,与煤层厚度恒定模型相比,曲线形态不发生改变;煤层厚度呈非线性变化时,频散曲线形态上可能发生改变.