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1201号强热带风暴“帕卡”是今年在西北太平洋及南海活动的第一个热带气旋,也是自1979年以来第一个在3月份生成于南海的热带气旋.本文利用多种资料,分析了“帕卡”强度及移动路径特点,并对引起其1移动路径及强度变化的原因做了进一步分析,主要得出以下结论:(1)“帕卡”生成过程中有两次冷空气影响南海,冷空气间隙暖湿的下垫面条件和较强的水汽和能量输送是系统迅速生成的主要原因;(2)西北太平洋副高的一次短周期活动,对“帕卡”移动路径变化起着重要作用;(3)空气的冷暖交汇作用加强了风暴中心的垂直对流结构,使“帕卡”登陆时仍然维持热带风暴的强度. 相似文献
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新疆克拉玛依市生态敏感性研究(英文) 总被引:2,自引:1,他引:1
Karamay City is a typical mining city, relying on oilfield exploration and development. After 60 years of construction and development, Karamay has become the first large oilfield and an important base of the national petroleum and petrochemical industry in China. Based on spatial analysis, and Geographic Information Systems (GIS) grid computing and overlay techniques, whilst considering the effect of oilfield development and aimed at the ecological problems of Karamay City in the Xinjiang Uygur Autonomous Region of China, we conducted research on the spatial characteristics of the comprehensive ecological sensitivity of Karamay. The ecological problems of natural environment evolution include soil erosion, land deserti-fication, soil salinization, and biodiversity reduction. The most significant disturbance factor from the activities of humans in this area is oilfield exploitation. This study carries out an analysis of single factor ecological problem sensitivity and integrated ecological sensitivity. The results of the research are as follows: (1) Soil erosion is relatively sensitive, especially in Karamay district, Dushanzi district, north of Urho district and west of Baijiantan district, which is mainly a result of the vertical dropping slopes, serious rainfall erosion and the distribution of scattered woodland. (2) The main types of land desertification are represented by high and moderate grade sensitivities, and high and extremely high sensitive areas are distributed in the intersection of Karamay and Baijiantan districts. This is due to evaporation exceeding rainfall in these areas, and the soil mainly consists of sand and is seldom covered by vegetation. (3) The soil salinizatiion sensitivity grades are mainly moderate, high and extremely high. The highly sensitive areas are mainly distributed in southeast of Baijiantan district, north and east of Karamay district and east of Urho district. The primary causes are evaporation exceeding rainfall and extreme human activities. (4) The main types of biodiversity sensitivity are light and moderate grade. Highly sensitive areas are located in the east and south of Karamay district, north of the Baiyang River basin and parts of the wetland areas. (5) Oil fields development areas are highly ecologically sensitive, which are located in the northern oilfields of Urho district, western oilfields of Baijiantan district, northwestern oilfields of Karamay district and central oilfields of Dushanzi district. (6) The main types of integrated ecological sen-sitivity are high and moderate. The high and extremely highly sensitive areas are located in the central and northern parts of Karamay district, and southwest of Baijiantan district. The evaluation results will provide guidance for the future planning and development, the protection of the ecological environment and the realization of harmonious social, economic, and ecological development in Karamay City. 相似文献
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1 接地和FCU插板的问题 在1999年9月,当地震计与前后台机联调成功后发现,类似机电干扰的尖角脉冲比较多,严重影响了记录的质量。初步分析后认为,接地不好可能是其中的一个原因。按CTS-1说明书的要求,将地线接至电源上的一个接地钮即可,但在实际工作中仍存在很大的干扰。后来,我们将地震计端口的所有屏蔽线接地和电源分别接地,干扰大为降低,起到了很好的作用。 2000年7月底CTS-1地震计出现了工作不稳定,尖角脉冲、矩形波干扰及反馈控制失调等问题(图1)。然后,有一个通道出现规则正弦波并停止工作(图2)。通过与武汉地震研… 相似文献
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内蒙古塔尔气地区花岗斑岩的形成时代与岩石成因 总被引:2,自引:1,他引:1
通过对内蒙古塔尔气地区花岗斑岩的野外地质特征、LA-ICP-MS锆石U-Pb年龄及地球化学特征的研究,讨论了该地区花岗斑岩的形成时代和成因机制。锆石U-Pb年龄及地球化学结果表明,塔尔气地区花岗斑岩形成于早白垩世136.5~126.4Ma;花岗斑岩具有高硅、富碱,弱过铝质(A/CNK=1.0~1.29),分异程度高的特点,属于高钾钙碱性系列,相对富集轻稀土元素和部分大离子亲石元素(Rb、Th、U、K),亏损高场强元素(Nb、Ta、Ti、P)。锆石Hf同位素组成表明,花岗斑岩具有较高的εHf(t)值(+7.19~+7.29),二阶段模式年龄为851~569Ma,暗示其可能起源于新元古代—早古生代期间从亏损地幔增生的地壳物质的部分熔融。结合区域地质资料分析,塔尔气花岗斑岩与研究区白音高老组火山岩可能为同期岩浆活动的产物,形成于伸展的构造环境。 相似文献