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51.
本文运用带通滤波分析方法,对四川省1981年7月由西南低涡等天气系统引起的大暴雨过程作了地面气象要素场的中尺度诊断分析。结果表明,带通滤波后的场具有明显的中尺度特征,其中一些物理量场的适当配置与6小时后的暴雨中心有较好的对应关系。说明了此带通滤波方法在实际业务预报中具有一定的使用价值。 相似文献
52.
地震前后垂直形变场动态演化的量化指标 总被引:3,自引:2,他引:1
提出一种表达垂直形变场动态演化过程的量化指标——区域应变率、应变集中度。在此基础上,对南北地震带各水准监测区近30年的垂直形变资料进行了实际计算.并结合具体震例进行了对比研究。结果表明:量化指标在一定程度上能够反映地震前后形变场的动态演化过程和地壳运动状态,对地震的中长期预报有一定的积极意义。 相似文献
53.
We analyzed data from 23 boreholes at 19 sites in central and eastern Canada, for the purpose of estimating ground surface temperature (GST) histories. These boreholes were logged down to at least 550 m depth with thermistor probes. Thermal conductivity measurements had been previously made at small depth intervals for the entire depth ranges of most of the boreholes. The temperature profiles of these boreholes do not indicate water disturbance. We estimated terrain effects for each borehole using a time dependent solid-angle method. The thermal perturbations caused by lakes or deforestation near the borehole sites are insignificant in most cases. However, four of the holes were found to be severely influenced by terrain effects. GSTs estimated from the borehole data less influenced by the terraineffects form two groups. The first group, which are generally from data of better quality, show a cold period near the end of the last century before the recent warming trend; the second show it 80–100 years earlier. We consider the former typical of the climate of the Boreal climatic region of Canada. The difference between the two groups may reflect the spacial variability of the climate. Four GST estimates do not belong to either type, and the reasons are discussed. 相似文献
54.
After the survey of pollution sources, a study on surface water quality assessment and forecast is given by means of grey
system method, fuzzy mathematical method and multiple-index method. Based on it, aquatic environment quality features, treatment
measures and environmental strategies of the area are proposed. The quality of aquatic environment of 5 rivers in the Tumen
River area is studied. The results show that the pollution of surface water is serious; water quality of most rivers is between
grade IV and V except the Hunchun River, being higher than grade IV standard; pollution levels of most rivers have been basically
controlled except the of Burhatong River, which is deteriorating gradually. Pollutants of the rivers are comparatively regular,
mainly are SS, COD, BOD, AR-OH, NH3-N. The main pollution trades are chemical fibre industry, pulp and paper making industry and mining industry. If the growth
rate of gross industrial product is higher than 25 percent under the encouraging-model of regional exploitation, the pollutants’
load will overtake the bearing capacity of aquatic environment. Thus some protection program against pollution must be worked
out in order to achieve the harmonious development of economy society and environment.
A project from “Studies on Earlier Stage of Regional Development” of the Chinese Academy of Sciences 相似文献
55.
56.
本文首先用有限元方法对几种不同的地形模型进行了分析。所得的结论是:由于实际地球表面地形的起伏不平,水准测量资料与地形之间具有相关性,即水准点高程变化与该点高程之间呈相关性。最后,本文对今后水准测量资料的分析处理提出了建议。 相似文献
57.
王发君 《中国海洋湖沼学报》1992,10(1):84-91
Based on a puff model . and together with the consideration of convection , dispersion and descent of suspended waste particles in marine environment , a numerical model is presented to predict the initial sedimentation of waste particles discharged from ocean outfalls in coastal waters and to compute the stable sedimentation rate in homogeneous trde current fields with water depth constant . When the time step selected is small enough , the results from this model agree well with that from the semi-analytical solution , and have sufficient precision for evaluating the impact on the environment caused by sedimentation of waste particles discharged from ocean outfalls. A numerical example is given for predicting the sedimentation of waste particles discharged in Heishijiao , Dalian . 相似文献
58.
本文在已有数据处理方法的基础上,利用近代数值逼近理论,给出了从时空域角度描述地壳垂直运动过程的一种具体的函数解析形式。最后给出了一个实际算例。 相似文献
59.
APPLICATION OF ANALYTIC HIERARCHY PROCESS TO ASSESSING THE ECOLOGICAL VULNERABILITY OF WETLANDS IN THE JIANGHAN PLAIN 总被引:5,自引:1,他引:4
WANGXue-lei NINGLong-mei HUWang-bin 《中国地理科学(英文版)》2003,13(3):272-276
Wetlands in the Jianghan Plain are important components of wetland types in lake area in the middle and lower reaches the Changjiang (Yangtze) River and they fulfill many uses and functions related to hydrology,waste assimilation, ecosystem productivity and biodiversity. Owing to natural factors and human activities, especially excessive reclamation from lakes, the shrinking process of the lakes has been accelerated. Wetland ecosystem has shown the characteristics of vulnerability. According to the analysis of wetland ecological function in the Jianghan Plain, this paper presented an index system related to productivity, stability and environmental capacity. By using the method of Analytic Hierarchy Process, we computed the values of the relative weights of the indexes, and evaluated the vulnerability level of the wetland ecosystem by the method of multi-indexes. The case study showed that the fragile extent of wetland ecosystem in the Jianghan Plain is 5.6. This means that the wetland ecosystem in the Jiang-han Plain is laid to the state of middle vulnerability. Therefore, the wetland conservation and eco-rehabilitation in the JiangJaan Plain should be paid attention to. 相似文献
60.