降水性层状云的微物理特征及人工增雨催化条件的研究

根据２７架次粒子测量系统的探测资料，综合分析了影响山东春，秋季降水云系的微特征，计算了探测层以上云中积分含水量，并依据综合分析结果对山东春，秋季降水性层状云的人工引晶剂量进行了探讨。     

华北北部场源前兆观测资料分析(一)──场源前兆特征与机制

1976年唐山地震前，在距震源很远的地区内都观测到一些前兆趋势变化，如重力、重力位二次徽商W△、水氧、地电阻率、水位和油井出油量等变化。作者认为这些变化不是由震源体直接引起的，而是在区域应力场的作用下，在某些活动断层附近，浅层岩，尤其是含水砂岩层和含油层受挤压出现的一些与地震有关的异常现象。其特征是：（1）异常范围大，可能在距震源很远的地方发生，但就同一种方法的多个观测点来说却又是局部的，即只有其中部分测点才能观测到异常，不少测点观测不到异常。（2）异常发生的时间大致相同。有些异常有同步变化的特征，如同时上升或同时下降。（3）临震前多数异常有恢复的趋势。这些特征与引起异常的机理有关。作者还从理论上计算了这种趋势异常量级，重力变化100×10-6cm／s2左右，重力位二次微商变化（1～2）×10－9／s2，地电阻率变化2％～3％，Rn变化7．4～11．1Bq／L，这样的变化量在活动断层附近的一些台站可能观测到。作者还研究了干旱降雨对某些前兆的影响，其影响量级可以被一些方法观测到，因此在确定是否是地震异常时，必须注意利用综合分析的方法排除干旱降雨的影响，减少异常的多解性。     

利用洞穴石笋的δ~(18)O和δ~(13)C重建3000a以来北京地区古气候和古环境——石花洞研究系列之三

首次提出用石笋中稳定同位素记录重建由降雨量和降水气团同位素组成所反映的古气候历史，从而为研究高分辨率的古季风气候信息开辟了新的途径。利用Ｈｅｎｄｙ准则、洞穴温度、研究区水系的δ１８ＯＨ２Ｏ值以及温度公式，证实了同位素分析结果的可靠性，ＣａＣＯ３－Ｈ２Ｏ之间存在同位素平衡分馏。对采自石花洞的石笋样品进行了分辨率约为２５ａ的δ１８Ｏ和δ１３Ｃ的分析测量，从而得到３０００ａ以来，北京地区古气候和古环境的变化信息     

地磁1年周期变化的响应函数

用通日月均值减去夜均值计算的月均值资料和Ｓｏｍｐｉ谱分析法分析了１４个台站的北向分量１年周期变化的振幅向相位，时段为１９８４－１９８８年。分析结果显示用Ｐ＾０ｎ（ｄｎｄ＝１，…，６）复合模式的估算的Ｃ值较合理。各台的Ｃ值比较一致。     

一次台风暴雨的初步分析

文章对1994年7月12～13日一次登陆台风造成的华北暴雨作了天气动力学诊断分析。分析表明，9406号台风登陆后，台风和太平洋副热带高压间形成的偏东南风低空急流，具有明显超地转特征，它是触发这次台风暴雨的关键系统。Q矢量诊断表明，Q矢量辐合区与暴雨位置较为一致。     

Adjoint Matching Condition for Parameterized Discontinuities－A Derivation Using Lagrangian-form Costfunction

The generalized adjoint property and adjoint matching condition for systems that contain discontinuous on / off switches are derived by a perturbation analysis of the Lagranging-form costfunction     

DOES WIND STRESS DEPEND ON SEA-STATE OR NOT? – A STATISTICAL ERROR ANALYSIS OF HEXMAX DATA

There have been several claims, either explicit or by implication, either based on experimental evidence or on theoretical reasoning, that the wind stress is modified by the stage of development of the wind sea. However, the overall evidence is weak, because theories are still incomplete and because it is questionable whether the sea-state effect, which is of the order of 10%, can be separated from experimental noise, which is of the order of 20%. In this paper a rigorous statistical analysis of HEXMAX data is pursued in order to establish the significance of sea-state effects. It appears that the enhanced drag, especially at high winds, which has already been established by previous analyses, cannot be attributed to the effect of young waves. The analysis provides no clues for the actual mechanism, which could be related to breaking or shoaling waves. As the effect of sea-state on wind stress is much smaller than the experimental noise level, it is hard to detect. Nevertheless, HEXMAX seems to contain a wave effect that is at the edge of statistical significance. It is, however, not the wave age itself that influences the drag, but a parameter involving wave height.Because the HEXMAX evidence is only indicative, we conclude that the issue set out in this paper cannot be answered on the basis of the HEXMAX data alone. It is recommended that error analyses are also carried out for other relevant observational data sets and that new measurements with suppressed noise will be taken up.     

Advances in energy-dispersive X-ray fluorescence

Recently, two new instruments for X-ray fluorescence analysis (XRF) with interesting features for geochemical applications came to the market. Both instruments were designed to improve the peak to background ratio, the principal factor limiting the sensitivity of XRF. Total reflection XRF (TXRF) was designed to analyse extremely small sample amounts. An instrument, using polarised X-rays (P-XRF) for excitation, is designed to reduce scattered background in spectra of bulk samples. The performance of both instruments was compared with conventional XRF-methods and ICP/MS. Results for GXR-1, GXR-2, GXR-3, GXR-4 and GXR-6 obtained with TXRF and P-XRF are in good agreement with literature data. The effective amount of sample, analysed by TXRF was 200 μg only and detection limits of ~ l μg/g were achieved. P-XRF shows considerable improved detection limits (0.25–0.5 μg/g) for bulk samples for elements with atomic numbers 42–51 (Mo-Sb) compared with conventional XRF-methods.     

城市化对北京平均气温的影响

本文利用北京（观象台）及周围几个气象台站月平均气温资料，滑动平均后，采用主成分分析方法，再进行倾向性分析，探讨了北京城市化对气平均气温的影响，估算对北京（观象台）气温记录的影响约为０．２１℃／３３ａ推断市中心二环路以内强烈地影响。     

影响上海市地价空间分布的区位因子分析

本文采用ＧＩＳ技术和多元线性回归分析方法，以土地批租地块为样本，分析上海市地价与城市区位因子的线性关系。回归分析结果表明；南京路，市中心和淮海路是影响上海市寺价空间差异的主要区位因子，外滩，次级商业中心和交通结节点对地价的影响很小，表明上海市地价的空间分布具有很高的向心性。