Some shifts in the population of the USSR

Using the preliminary results of the 1979 census, the authors analyze trends in the distribution of the population of the USSR. Topics considered include the role of natural increase in the redistribution of the population, the relationship between economic development and the rate of population growth in Siberia, the effects of increasing rural-urban migration, and changes in the number and distribution of large cities.     

印度尼西亚松巴哇岛西南Batu Hijau斑岩铜—金矿例研究

世界级的Ｂａｔｕ Ｈｉｊａｕ斑岩铜－金矿床位于印度尼西亚松巴哇岛,１９９０年被Ｎｅｗｍｏｎｔ公司发现。这类矿床在西太平洋其他一些岛弧斑岩矿床是是比较典型的。它们在与火成岩的关系、产出形态、热液蚀变和矿化种类等方面具有共同特征。矿化主要发生在闪长岩和安山质闪火山岩内的英闪岩侵入染岩中。主侵入体在矿床中部形成一个柱状岩株,控制了大部分高品位铜的金矿化。钾蚀变核心带从内向外渐变成广泛的绿磐岩蚀变,这两种     

用探地雷达和谱激发极化法追踪地下污染

我们把探地雷达（ＧＰＲ）与谱激发极化法（ＳＩＰ）相结合,去查明与巴西巴伊亚萨尔瓦多附近一个石油化工企业所产生非水相重液（ＤＮＡＰＬｓ）的一次大量泄漏有关的水文地质构造,地下通道及残留污染物积存处所。这些有害的有机化学物质已浸入到上部潜水层并深深地渗入一个厚且范围大的半承压多层含水层系。经处理的ＧＰＲ断面可用来填绘出潜水面起伏,详细划分上部潜水带层序,并重建流过它的污染前缘的总体形态。电阻率和激发极     

数理统计学方法在中国水产资源研究中的应用概述

数理统计学方法对于水产资源学的发展发挥了极其重要的推动作用。数理统计方法在中国水产资源学的应用．起步于50年代．发展于60到80年代，90年代以后进入了一个崭新的发展阶段。作为一个发展中国家，同世界其他国家相比．我们将面临着更多的机遇与挑战。     

中国区域性极端降水事件及人口经济暴露度研究

This paper tests the idea of substituting the atmospheric observations with atmospheric reanalysis when setting up a coupled data assimilation system.The paper focuses on the quantification of the effects on the oceanic analysis resulted from this substitution and designs four different assimilation schemes for such a substitution.A coupled Lorenz96 system is constructed and an ensemble Kalman filter is adopted.The atmospheric reanalysis and oceanic observations are assimilated into the system and the analysis quality is compared to a benchmark experiment where both atmospheric and oceanic observations are assimilated.Four schemes are designed for assimilating the reanalysis and they differ in the generation of the perturbed observation ensemble and the representation of the error covariance matrix.The results show that when the reanalysis is assimilated directly as independent observations,the root-mean-square error increase of oceanic analysis relative to the benchmark is less than 16%in the perfect model framework;in the biased model case,the increase is less than 22%.This result is robust with sufficient ensemble size and reasonable atmospheric observation quality(e.g.,frequency,noisiness,and density).If the observation is overly noisy,infrequent,sparse,or the ensemble size is insufficiently small,the analysis deterioration caused by the substitution is less severe since the analysis quality of the benchmark also deteriorates significantly due to worse observations and undersampling.The results from different assimilation schemes highlight the importance of two factors:accurate representation of the error covariance of the reanalysis and the temporal coherence along each ensemble member,which are crucial for the analysis quality of the substitution experiment.