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利用NCEP/FNL再分析资料和中尺度数值模拟方法探讨2018年8月27日—9月1日季风低压环境下广东特大暴雨过程的形成成因。利用扰动天气图方法分析发现,季风低压和西南急流为此次广东暴雨过程提供了有利的水汽条件和能量条件。熵变零线位置与降水落区位置有较好的对应,零线处能量有最大累积,有利于暴雨的发生发展,对预报暴雨降水落区有一定的指示意义。为进一步验证季风低压的影响机制,构建不同季风低压尺度的敏感性试验,即通过滤去季风低压环流中的扰动分量来改变季风低压的强度。结果表明:暴雨强度与季风低压尺度和强度存在密切的关系。当季风低压强度较强时,暴雨过程总雨量强;当季风低压强度较弱时,降水大为减少甚至无降水。诊断分析指出,能量螺旋度指数能够较好反映出不同情形下降水发生发展,在季风低压背景下,暴雨区能量螺旋度指数较大,降水强度较强。反之,随着季风低压强度减弱,能量螺旋度指数减小,降水减弱。 相似文献
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全国第二次土地调查数据库利用以后,城市建设用地审批、大型的线状用地、土地复垦、矿山治理等工程的前期可研及预审工作等基本都以二调数据为基础数据。将正确的用地红线用ArcGis软件处理成面文件(.Shp),然后把处理后的.shp文件复制到二调数据库里的KCDJ层里。再使用农村土地调查专用软件导出各级用地面积汇总表。通过文中介绍的方法,可以实现快速、准确的制作指定范围的各种地类面积表。 相似文献
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The structural activities took place extensively in the Asia continent during the Cenozoic era owing to the strong continent-to-continent
collision and continuous compression between the India Plate and the Eurasia Plate. Huang Jiqing called such structural activities
Himalayan movement. China’s sedimentary basins developed and took shape mainly during the Himalayan movement period. It is
also the main period for formation and development of the oil and gas reservoirs. Of 366 large and medium-sized oil and gas
fields currently found in China, 212 reservoirs were formed in the Neogene-Quaternary period. The proportion is as high as
68.2%. The oil and gas migration and accumulation in the latest geological period, which were controlled by the times, properties,
styles and strength of the Himalayan movement, took place mainly in eight regions, such as the low uplift area of Bohai Sea,
the onshore faulted sag area of Bohai Bay, anticlinorium zone in Daqing, the foreland fold-and-thrust belt in West China,
the tilted structural zone in West China, the cratonic palaeohigh in the Tarim Basin, the zone of fault and fold belt in the
East Sichuan Basin, and the biological gas zone in the East Qaidam Basin. The oil and gas pool formations in those regions
have their own characteristics. With the great potential and broad prospect, those regions are the main exploration areas
in China in the future. 相似文献
80.
Linking Tarim Basin sea retreat (west China) and Asian aridification in the late Eocene 总被引:1,自引:0,他引:1
R. Bosboom G. Dupont‐Nivet A. Grothe H. Brinkhuis G. Villa O. Mandic M. Stoica W. Huang W. Yang Z. Guo W. Krijgsman 《Basin Research》2014,26(5):621-640
The Tarim Basin in western China formed the easternmost margin of a shallow epicontinental sea that extended across Eurasia and was well connected to the western Tethys during the Paleogene. Climate modelling studies suggest that the westward retreat of this sea from Central Asia may have been as important as the Tibetan Plateau uplift in forcing aridification and monsoon intensification in the Asian continental interior due to the redistribution of the land‐sea thermal contrast. However, testing of this hypothesis is hindered by poor constraints on the timing and precise palaeogeographic dynamics of the retreat. Here, we present an improved integrated bio‐ and magnetostratigraphic chronological framework of the previously studied marine to continental transition in the southwest Tarim Basin along the Pamir and West Kunlun Shan, allowing us to better constrain its timing, cause and palaeoenvironmental impact. The sea retreat is assigned a latest Lutetian–earliest Bartonian age (ca. 41 Ma; correlation of the last marine sediments to calcareous nannofossil Zone CP14 and correlation of the first continental red beds to the base of magnetochron C18r). Higher up in the continental deposits, a major hiatus includes the Eocene–Oligocene transition (ca. 34 Ma). This suggests the Tarim Basin was hydrologically connected to the Tethyan marine Realm until at least the earliest Oligocene and had not yet been closed by uplift of the Pamir–Kunlun orogenic system. The westward sea retreat at ca. 41 Ma and the disconformity at the Eocene–Oligocene transition are both time‐equivalent with reported Asian aridification steps, suggesting that, consistent with climate modelling results, the sea acted as an important moisture source for the Asian continental interior. 相似文献