估计防雹工作经济效益的物理方法

人工防雹是直接抗灾保收的一项气象科学试验。其效果如何,是人们普遍关注的一个问题。防雹效果包括科学效果和经济效益。目前,已经提出了不少检验防雹科学效果的方法,但还缺乏估计其经济效益的客观方法。苏联学者提出过一些估计防雹工作经济效益的方法,但绝大多数是基于防雹工作的统计效果而     

广西某矿田中硫盐矿物的再研究

A great variety of sulfosalt minerals occur in signifiennt amount over a wide area within the ore field under consideration.In some deposits in this area,sulfosalts are so abundant that they are even mined as major industrial ores for lead and zine.Ten sulfosalts have so far been discovered,including jamesonite.boulangerite,franckeite,stannite,tetrahedrite.bournonite,berthierite,diaphorite,geocronite and jurdanite,among which jamesonite is the most important.     

访美见闻

去年秋季,我作为中国气象学会回访美国气象学会代表团的成员之一,在美国进行了为期半月余的访问。代表团有时一路,有时分作两路活动。我参加的一路,先后到达了波士顿、丹佛、波尔多、迈阿密、阿什维尔、华盛顿和纽约。参观了美国的气象学会、一些气象中心和气象业务、科研部门以及几个著名院校的气象系、大气污染专业等。在美国朋友的热情友     

苏联对防雹工作经济效果的估计

苏联开展人工防雹工作已有近二十年的历史。到1979年,全苏联10个防雹部门所属53个防雹小分队的设防区上所防护的农作物总面积已超过650万公顷,比1968年增加了一倍多。在经济作物种植面积较大而雹灾又重的地区(如摩尔达维亚等),人工防雹已成为抗灾保收的重要措施之一。人工防雹是直接为农业生产服务的一项气象科学试验,其经济效果如何,是人们十分关注的一个问题。苏联的防雹专家们从六十年代后期起,就对如何估计防雹工作的经济效果开展了研究工作,目     

群体绝迹:生命的严酷事实

在地球上,已知最早群体绝迹中,百分之七十的澡类灭绝于6.5亿年以前,马萨诸塞州坎布里奇市哈佛大学的安德烈H.克洛尔和瑞典隆德大学的Gonzalo vidal报道,这项发现是根据对斯堪的纳维亚、波罗的海地区、格陵兰东部以及新近在澳大     

岩溶与水库诱发地震

二十世纪六十年代,人们注意到修建水库有时能改变当地地震活动的特点,甚至在地震活动水平不高的地区诱发强烈地震。为探索水库诱发地震的形成条件,许多地震工作者对各类水库进行了考察。有的研究工作指出,库区岩石条件对水库诱震有着明显的影响;岩溶是水库诱震的有利条件。作者对国内外大量水库地震震例进行了分析,发现半数诱震水库位于碳酸岩地区,且发震地段多在岩溶发育区。     

山东昌乐-临朐火山岩流体包裹体成分研究及其意义

山东昌乐-临朐地区火山岩内的橄榄石和辉石中舍有大量的流体包裹体,流体来源于地幔。采用激光拉曼光谱技术对部分火山岩流体包裹体样品进行分析,获得了包裹体中挥发分的成分和相对含量。结果表明,该区岩浆中舍有大量的CO2和水,CO2是气相包裹体中的主要成分。同时在包裹体内存在H2、CO、H2S、CH4等还原性气体,说明流体来源于还原环境。此外,少量低碳烷烃的出现为天然气无机成因提供了证据。     

Variations of δ^18 O in Precipitation along Vapor Transport Paths

Three sampling cross sections along the south path starting from the Tropics through the vapor passage in the Yunnan-Guizhou Plateau to the middle-low reaches of the Yangtze River, the north path from West China, via North China, to Japan under the westerlies, and the plateau path from South Asia over the Himalayas to the northern Tibetan Plateau, are set up, based on the IAEA (International Atomic Energy Agency)/WMO global survey network and sampling sites on the Tibetan Plateau. The variations, and the relationship with precipitation and temperature, of the δ^18 O in precipitation along the three cross sections are analyzed and compared. Along the south path, the seasonal differences of mean δ^18 O in precipitation are small at the stations located in the Tropics, but increase markedly from Bangkok towards the north, with the 51so in the rainy season smaller than inthe dry season. The δ^18 O sovalues in precipitation fluctuate on the whole, which shows that there are different vapor sources. Along the north path, the seasonal differences of the mean δ^18 O in precipitation for the stations in the west of Zhengzhou are all greater than in the east of Zhengzhou. During the cold half of the year, the mean δ^18 O in precipitation reaches its minimum at Uriimqi with the lowest temperature due to the wide, cold high pressure over Mongolia, then increases gradually with longitude, and remains at roughly the same level at the stations eastward from Zhengzhou. During the warm half of the year, the δ^18 O values in precipitation are lower in the east than in the west, markedly influenced by the summer monsoon over East Asia. Along the plateau path, the mean δ^18 O values in precipitation in the rainy season are correspondingly high in the southern parts of the Indian subcontinent, and then decrease gradually with latitude. A sharp depletion of the stable isotopic compositions in precipitation takes place due to the very strong rainout of the stable isotopic compositions in vapor in the process of lifting over the southern slope of the Himalayas. The low level of the δ^18 O in precipitation is from Nyalam to the Tanggula Mountains during the rainy season,but δ^18 O increases persistently with increasing latitude from the Tanggula Mountains to the northern Tibetan Plateau because of the replenishment of vapor with relatively heavy stable isotopic compositions originating from the inner plateau. During the dry season, the mean δ^18 O values in precipitation basically decrease along the path from the south to the north. Generally, the mean δ^18 O in precipitation during the rainy season is lower than in the dry season for the regions controlled by the monsoons over South Asia or the plateau, and opposite for the regions without a monsoon or with a weak monsoon.