Molecular Line Parameters for the “MASTER” (Millimeter Wave Acquisitions for Stratosphere/Troposphere Exchange Research) Database

In order to investigate the upper troposphere/lower stratosphere (UTLS) region of the earth's atmosphere, ESA/ESTEC (European space agency) is considering the opportunity to develop the spaceborne limb sounding millimeter sensor “MASTER” (millimeter wave acquisitions for stratosphere/troposphere exchange research). This instrument is part of the “atmospheric composition explorer for chemistry and climate interactions” (ACECHEM) project. In addition, ESA/ESTEC is developing the “MARSCHALS” (millimeter-wave airborne receiver for spectroscopic characterization of atmospheric limb sounding) airborne instrument which will demonstrate the feasibility of MASTER. The present paper describes the line-by-line database which was generated in order to meet at best the needs of the MASTER (or MARSCHALS) instrument. The linelist involves line positions, line intensities, line broadening and line shift parameters in the 294–305, 316–325, 342–348, 497–506 and 624–626 GHz spectral microwindows. This database was first generated for the target molecules for MASTER (H₂O, O₃, N₂O, CO, O₂, HNO₃, HCl, ClO, CH₃Cl, BrO). In addition, ten additional molecules (SO₂, NO₂, OCS, H₂CO, HOCl, HCN, H₂O₂, COF₂, HO₂ and HOBr) had also to be considered in the database as “possible interfering species” for the retrieval of the target molecules of MASTER. The line parameters were derived, depending on their estimated accuracy, (i) from a combination of spectral parameters included in the JPL and HITRAN catalogs (ii) from data taken into the literature or (iii) using data obtained through experimental measurements (and/or) calculations performed during the present study.     

基于连续小波变换的大地电磁信号谱估计方法

在基于连续小波变换的大地电磁信号谱估计方法中 ,通过引入整体平均、小波系数收缩和显著性检验等统计技术 ,以提高谱估计的精度 .文中同时讨论了连续小波变换中各种参数的选取问题 ,给出了Morlet小波函数中尺度与傅里叶频率之间转换的经验公式 ,并给出了谱估计的具体算法 .结果表明 ,本文方法可有效压制较强的白噪声和局部相关噪声 .与FFT谱估计方法相比 ,该方法大大降低了对信号记录长度的要求 ,因而对大地电磁信号的处理有实际意义 .     

SIMS determination of trace element partition coefficients between garnet, clinopyroxene and hydrous basaltic liquids at 2–7.5 GPa and 1080–1200°C

Trace element partition coefficients (D's) for up to 13 REE, Nb, Ta, Zr, Hf, Sr and Y have been determined by SIMS analysis of seven garnets, four clinopyroxenes, one orthopyroxene and one phlogopite crystallized from an undoped basanite and a lightly doped (200 ppm Nb, Ta and Hf) quartz tholeiite. Experiments were conducted at 2–7.5 GPa, achieving near-liquidus crystallization at relatively low temperatures of 1080–1200°C under strongly hydrous conditions (5–27 wt.% added water). Garnet and pyroxene D_REE show a parabolic pattern when plotted against ionic radius, and conform closely to the lattice strain model of Blundy and Wood (Blundy, J.D., Wood, B.J., 1994. Prediction of crystal–melt partition coefficients from elastic moduli. Nature 372, 452–454). Comparison, at constant pressure, between hydrous and anhydrous values of the strain-free partition coefficient (D₀) for the large cation sites of garnet and clinopyroxene reveals the relative importance of temperature and melt water content on partitioning. In the case of garnet, the effect of lower temperature, which serves to increase D₀, and higher water content, which serves to decrease D₀, counteract each other to the extent that water has little effect on garnet–melt D₀ values. In contrast, the effect of water on clinopyroxene–melt D₀ overwhelms the effect of temperature, such that D₀ is significantly lower under hydrous conditions. For both minerals, however, the lower temperature of the hydrous experiments tends to tighten the partitioning parabolas, increasing fractionation of light from heavy REE compared to anhydrous experiments.

Three sets of near-liquidus clinopyroxene–garnet two-mineral D values increase the range of published experimental determinations, but show significant differences from natural two-mineral D's determined for subsolidus mineral pairs. Similar behaviour is observed for the first experimental data for orthopyroxene–clinopyroxene two-mineral D's when compared with natural data. These differences are in large part of a consequence of the subsolidus equilibration temperatures and compositions of natural mineral pairs. Great care should therefore be taken when using natural mineral–mineral partition coefficients to interpret magmatic processes.

The new data for strongly hydrous compositions suggest that fractionation of Zr–Hf–Sm by garnet decreases with increasing depth. Thus, melts leaving a garnet-dominated residuum at depths of about 200 km or greater may preserve source Zr/Hf and Hf/Sm. This contrasts with melting at shallower depths where both garnet and clinopyroxene will cause Zr–Hf–Sm fractionation. Also, at shallower depths, clinopyroxene-dominated fractionation may produce a positive Sr spike in melts from spinel lherzolite, but for garnet lherzolite melting, no Sr spike will result. Conversely, clinopyroxene megacrysts with negative Sr spikes may crystallize from magmas without anomalous Sr contents when plotted on mantle compatibility diagrams. Because the characteristics of strongly hydrous silicate melt and solute-rich aqueous fluid converge at high pressure, the hydrous data presented here are particularly pertinent to modelling processes in subduction zones, where aqueous fluids may have an important metasomatic role.     

A statistical analysis of sunspot groups hosting M and X flares

In this paper we present the results obtained from a statistical analysis carried out by correlating sunspot‐group data collected at the INAF‐Catania Astrophysical Observatory and in the NOAA reports with data on Mand X flares obtained by the GOES‐8 satellite in the soft X‐ray range during the period January 1996–June 2003. These results allow us to provide a quantitative estimate of the parameters typical for an active region with very energetic flares. Moreover, the analysis of the flare productivity as a function of the group evolutionary stage indicates that the flaring probability of sunspots slightly increases with the spot age during the first passage across the solar disk, and that flaring groups are characterized by longer lifetimes than non‐flaring ones. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

加筋效应对群桩相互作用系数的影响

群桩相互作用系数通常是采用平面应变模型进行分析,其研究方法具有较多的近似性。基于更为严格的虚拟桩模型,应用群桩相互作用的积分方程解答,以两桩相互作用的基本模型为例,研究加筋效应对群桩相互作用的影响。与弹性理论法和Mylonakis & Gazetas解答的对比表明,加筋效应对群桩相互作用系数有着较为明显的影响,并指出Mylonakis & Gazetas基于剪切位移法所得解答中存在的一些主要问题。     

A neighbor decay cellular automata approach for simulating urban expansion based on particle swarm intelligence

Simulation and quantitative analysis of urban land use change are effective ways to investigate urban form evolution. Cellular Automata (CA) has been used as a convenient and useful tool for simulating urban land use change. However, the key issue for CA models is the definition of the transition rules, and a number of statistical or artificial intelligence methods may be used to obtain the optimal rules. Neighborhood configuration is a basic component of transition rules, and is characterized by a distance decay effect. However, many CA models do not consider the neighbor decay effect in cellular space. This paper presents a neighbor decay cellular automata model based on particle swarm optimization (PSO-NDCA). We used particle swarm optimization (PSO) to find transition rules and considered the decay effect of the cellular neighborhood. A negative power exponential function was used to compute the decay coefficient of the cellular neighborhood in the model. By calculating the cumulative differences between simulation results and the sample data, the PSO automatically searched for the optimal combination of parameters of the transition rules. Using Xiamen City as a case study, we simulated urban land use changes for the periods 1992–1997 and 2002–2007. Results showed that the PSO-NDCA model had a higher prediction accuracy for built-up land, and a higher overall accuracy and Kappa coefficient than the urban CA model based on particle swarm optimization. The study demonstrates that there exist optimal neighborhood decay coefficients in accordance with the regional characteristics of an area. Urban CA modelling should take into account the role of neighborhood decay.     

基于RPC模型的ZY-3正射纠正研究

采用基于RPC模型进行ZY-3影像正射纠正处理时,当使用全局布点控制方案时控制点增加到12个以上后,对整景影像的纠正精度影响不明显,且由于选取多个高精度的控制点非常困难,而有时控制点的增加并不一定能带来精度的提高。本文通过采用几种不同的控制点布设方案对同一景ZY-3影像进行正射纠正,并对几种方案的纠正成果进行了精度比较和分析,从而进一步证实了选择合适的控制点布设方案和控制点数量大大提高ZY-3影像的纠正质量和纠正效率。     

火星探测器行星际定轨两种数据处理方案比较

计算了由于形状、姿态和表面性质不准确导致火星探测器行星际定轨存在较大光压模型误差时,两种不同定轨方案(方案1只估计光压系数,方案2同时估计光压系数和随机加速度)对光压模型误差的补偿效果。在方案2中建立了高斯马尔科夫模型表征光压模型导致的加速度误差,并选取了合适的随机模型参数。仿真分析表明方案2可以有效补偿光压模型误差,避免滤波发散,提高定轨精度。     

一种基于复共线性分析的RPC参数优选法

推导了求解有理多项式系数(RPC)的严密误差方程,从分析误差方程设计矩阵列向量间的复共线性着手,提出了一种去相关的RPC参数优选方法。对一景SPOT-5 HRG 1A级影像进行实验,结果表明,当地面控制点稀疏时,通过优选20~30个RPC参数,可以很好地消除参数间的相关性,有效消除有理函数模型(RFM)在地形拟合中出现的振荡现象,可明显提高RPC参数求解和RFM的影像几何处理精度。当地面控制点足够多时,利用此方法优选的RPC参数进行地形拟合的结果与用常规最小二乘法求解的78个RPC参数实施地形拟合的结果完全一致。     

玉树MS7.1级地震前的形变应变场变化特征

基于1999～2007年和2007～2009年的GPS站点观测数据计算的速度场,分析了青藏亚板块的运动特征.利用块体(旋转与线性应变)弹性运动公式计算可可西里-巴颜喀拉块体和羌唐块体的应变率、可可西里-玉树断裂带的运动速度和应变率,研究了玉树7.1级地震前的形变应变特征.结果表明:可可西里-巴颜喀拉块体处于青藏亚板块运...