A partial susceptibility approach to analysing the magnetic properties of environmental materials: a case study   总被引：2，自引：0，他引：2  

Shanju Xie  John A. Dearing  & Jan Bloemendal 《Geophysical Journal International》1999,138(3):851-856

An approach to expressing the magnetic properties of environmental materials in terms of the contributions of the magnetic susceptibilities of specific magnetic components is reported. The approach links the partial susceptibilities of discrete particles, domains or mineral fractions with the concentration-dependent parameters by means of multiple linear regression methods. The case study, using the Liverpool street dust data set, demonstrates that the technique is able to model the contributions of the main magnetic components satisfactorily. Several factors may have a significant impact on the regression results. These include the validity of the linear proportional relationships between partial susceptibilities and the relevant concentration-dependent parameters, the adequacy of the variable selection procedure and the regression model, and the suitability of certain magnetic parameters.  相似文献   

Measurement and Estimative Models of Glacier Mass Balance in China   总被引：1，自引：0，他引：1  

Xie Zichu  Han Jiankang  Liu Chaohai  & Liu Shiyin 《Geografiska Annaler: Series A, Physical Geography》1999,81(4):791-796

Attributed to high altitude and inland location, the glaciers in China are characterized by very low temperature. The non-negligible contribution of up to 25% of superimposed ice to the net balance has been taken into account in the mass budget calculation. So too has the internal the accumulation in the infiltration zone of the accumulation area.
The prevailing monsoon climate delivers most of the annual precipitation over glaciated areas of China in the summer, making the major accumulation on those glaciers coincide with the ablation period. Therefore, the annual mass balance should be calculated neither by giving the place of annual accumulation to winter balance, nor annual ablation to summer balance. Rather, it is better done by net accumulation and net ablation during the year. In order to get the annual accumulation and the annual ablation on a glacier, the summer precipitation should be measured at the same time.
Frequent snowfall in the summer season results in intensive fluctuation of surface albedo. This means that, for lack of data on the extremes of ablation, reconstruction of mass balance is unsatisfactory when based on the relationships of accumulation and ablation to precipitation and temperature. The establishment of models, either on the relationship of multi-year mass balance to the equilibrium line and the mass balance gradient of a glacier in steady-state, or on the maximum entropy principle and the hydrometeorological data, helps to estimate the multi-year mass balance of the glacierized area in a mountain range or drainage basin.  相似文献   

和田河流域水资源与生态环境变化及其对策研究   总被引：8，自引：1，他引：7  

刘志辉  谢永琴  穆建军  樊夙昱 《干旱区地理》1999,22(3):51-56

和田河流域光,热,水、土地资源丰富,农牧业 潜力很大,然而该流域生态环境极其脆弱,环境灾害多发,水资源开发利用及区域发展不可避免地其生态环境产生很大影响。本文从多个侧面阐述了该流域水资源与生态环境的相互关系和影响,并提出了相应的对策和建议。  相似文献   

天津泰达城区发展问题初探   总被引：1，自引：0，他引：1  

谢晋宇 《地域研究与开发》1999,18(1):58-60

对泰达城区发展的定位问题进行了论述,认为泰达城区发展应该坚持与塘沽和滨海新区的区域规划相配合,将塘沽和泰达作为一个城市系统来规划,在城市新兴功能方面可以进行高起点、高品质的建设等,以增加泰达城区的吸引力  相似文献   

GPS中CCD技术的原理与应用   总被引：2，自引：2，他引：0  

谢世杰  高启贵 《测绘工程》1999,8(4):12-17

码／载波相位扩散技术可使单频ＧＰＳ接收机的测程从２０ｋｍ急剧扩大到４００ｋｍ。本文叙述其简单原理与实际应用。  相似文献   

联合战役地形分析     

庄久昌  王飞 《测绘学院学报》1999,(3)

首次提出联合战役地形分析的概念,并分析了联合战役地形分析应用的主要时机和要求。论述确定地形分析基本任务的逻辑关系,并分别研究了联合战役地形分析各基本内容的概念与分析方法。  相似文献   

光化学烟雾的控制试验   总被引：2，自引：0，他引：2  

纪飞  苏文颖 《应用气象学报》1999,10(4):491-497

利用MM5与RADM的耦合模式,设计了3个削减源排放的试验,用以探讨控制光化学污染的有效途径。试验结果表明,在NMHC/NOx比值很大的前提条件下,NOx地面源排放的削减对降低大气中O3含量的作用最显著,而削减NMHC对降低大气中PAN含量的作用明显,同时削减NMHC和NOx是降低大气光化学污染强度的最佳途径。  相似文献   

江西“98.6”连续大暴雨过程的θ_(se)场特征   总被引：4，自引：0，他引：4  

谢梦莉 《气象》1999,25(9):49-51

通过分析江西“９８．６”连续大暴雨过程的θｓｅ场特征,得到了用θｓｅ场作暴雨落区预报的关卡发点,指出了对暴雨的分析和预报,θｓｅ场分析法简便易行,优于天气形势分析法。  相似文献   

降雨年际气候变化的非线性动力统计模拟预测   总被引：2，自引：0，他引：2       下载免费PDF全文

严华生  曹杰  谢应齐  季崇萍  郭世昌 《气象学报》1999,57(4):502-508

文中应用非线性动力统计方法来模拟降水年际气候变化。经过对中国４２ 个测点近百年降雨变化的模拟预测检验,取得了较好的效果,并得出了一些有意义的结论。关键词：非线性,动力统计,模拟预测。  相似文献   

基本气流在局域流型演化过程中的作用   总被引：3，自引：0，他引：3       下载免费PDF全文

罗哲贤  谢金南  马镜娴 《大气科学》1999,23(3):308-315

用一个β平面准地转正压模式,实施了5组时间积分为72个模式日的试验,分析了不同基本气流对局域流型演化特征的作用。结果指出:强的基本气流相应于持续性干旱流型;弱的基本气流相应于间歇性的干旱流型。  相似文献