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121.
2021年秋季江西出现范围广、强度强、持续时间长的高温天气过程,多项气温指标创历史同期新高,10月1—5日全省仍出现20站次危险性高温天气。利用江西省93个国家气象观测站、MICAPS观测资料以及NCEP/NCAR再分析资料,对此次罕见秋季异常高温天气的过程的特征及环流背景场进行了分析讨论。结果表明:1)西太平洋副热带高压是江西秋季高温天气的主导系统,强大的副热带高压控制区内盛行的下沉运动产生大气绝热加热是此次秋季异常高温的主要形成原因。同时,西风急流偏强以及南亚高压撤退时间偏晚,使得西风带短波槽脊活动不易影响到副热带地区,有利于副热带高压强度和位置的稳定维持,冷空气难以南下到达长江中下游地区,高温天气得以发展。2)中低层暖平流输送有利于局地温度升高从而形成高温天气,江西上空对流层异常增温一定程度上加剧了该地区秋季高温的持续。3)江西境内水汽通量散度呈现负距平,表明水汽辐散程度弱于常年同期,未出现水汽输送的大幅减弱。同时,对流层中下层存在一定的上升气流,部分水汽凝结形成降水。因此,异常高温期间未出现严重干旱。 相似文献
122.
Paleoproterozoic supracrustal materials have been widely identified in North China Craton, such as the Liaohe-, Hutuo-and Lyuliang groups. The Liaohe Group in the eastern part of the North China Craton is dominated by deformed and metamorphosed sedimentary and volcanic successions. Compared with that of the coeval volcanic rocks, geochemistry of the sedimentary rocks from the Liaohe Group has rarely been studied in detail, which can possibly provide information on the paleoclimate and provenance. The authors analyzed the whole-rock and detrital zircon geochemistry of sedimentary rocks from the Liaohe Group against a uniform process and proposed their different ways of paleoweathering of the lower and upper formations. That is to say, although the lower and upper formations within the Liaohe Group might be derived from the similar source composition in a tectonically active setting, the paleoclimate that they experienced was not exactly the same. The predominant derivations are the Paleoproterozoic granitoids and basalts within the Liaohe Group, with minor input of Archean continental crust. This study highlights the contributions of the Paleoproterozoic mafic sources, which has been generally overlooked in the previous researches. 相似文献
123.
全面分析了气候变化给企业带来的机遇与挑战。全球契约的"关注气候"倡议为企业响应全球号召应对气候变化带来了机遇,全球契约是全球企业共同应对气候变化、实现企业社会责任和树立企业形象的良好平台。另外,通过调查研究分析了中国民营企业应对气候变化的现状,并提出了相关政策建议。 相似文献
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针对探空观测资料使用造成的某些区域GRAPES分析场存在虚假的高、低压系统问题,该文通过对比全球探空资料的位势高度观测与NCEP分析场,统计站点中观测质量较差的时次出现频数,确定探空位势高度观测黑名单。研究表明:500 hPa在印度地区、北大西洋和南极洲附近的探空位势高度观测与NCEP分析场的均方根误差在30 gpm以上的站点较多,且位势高度观测不可靠观测比率为20%以上的站点主要集中这些区域,以上观测站均列入黑名单。文中在GRAPES全球三维变分分析场的质量控制中加入探空位势高度观测黑名单检查,通过6 h分析预报循环试验表明:探空位势高度观测黑名单检查能有效提高分析场质量,GRAPES位势高度分析场在南极洲附近和印度地区有所改善。 相似文献
128.
准噶尔盆地西北缘侏罗系陆相碎屑岩储层的岩性差异较大,岩性对物性的控制作用明显。储层的孔隙类型多样,不同类型的孔隙在发育规模、丰度及有效性方面都存在显差异,次生溶蚀孔隙、原生粒间孔隙和残余粒间孔隙是最重要的有效孔隙类型。储层渗透率与孔隙度之间存在较好的半对数相关关系。通过设置一定的孔隙度和渗透率参数界线,对储层储集性能进行评价,将侏罗系储层的孔渗性能划分为5个级别,可与当前流行的砂岩储层孔渗性能分级相对应。通过对大量压汞参数样本的聚类分析,将储层的孔隙结构划分为4个类型。通过各类参数统计及曲线形态对比,对孔隙结构类型进行了定量结合定性的优劣评价。最后,结合孔渗性能级别、储集空间类型、孔隙结构类型、岩性等特征,对准噶尔盆地西北缘侏罗系储层进行了综合分类评价。 相似文献
129.
The Wenchuan Earthquake (May 12, 2008), Sichuan Province,China, and resulting geohazards 总被引:14,自引:5,他引:14
Peng Cui Xiao-Qing Chen Ying-Yan Zhu Feng-Huan Su Fang-Qiang Wei Yong-Shun Han Hong-Jiang Liu Jian-Qi Zhuang 《Natural Hazards》2011,56(1):19-36
On Monday, May 12, 2008, a devastating mega-earthquake of magnitude 8.0 struck the Wenchuan area, northwestern Sichuan Province,
China. The focal mechanism of the earthquake was successive massive rock fracturing 15 km in depth at Yingxiu. Seismic analysis
confirms that the major shock occurred on the Beichuan–Yingxiu Fault and that aftershocks rapidly extended in a straight northeast–southeast
direction along the Longmenshan Fault zone. Fatalities approaching a total of 15,000 occurred, with a significant number resulting
from four types of seismically triggered geohazards—rock avalanches and landslides, landslide-dammed lakes (“earthquake lakes”),
and debris flows. China Geological Survey has identified 4,970 potentially risky sites, 1,701 landslides, 1,844 rock avalanches,
515 debris flows, and 1,093 unstable slopes. Rock avalanches and landslides caused many fatalities directly and disrupted
the transportation system, extensively disrupting rescue efforts and thereby causing additional fatalities. Landslide-dammed
lakes not only flooded human habitats in upstream areas but also posed threats to potentially inundated downstream areas with
large populations. Debris flows become the most remarkable geohazards featured by increasing number, high frequency, and low
triggering rainfall. Earthquake-triggered geohazards sequentially induced and transformed to additional hazards. For example,
debris flows occurred on rock avalanches and landslides, followed by landslide-dammed lakes, and then by additional debris
flows and breakouts of the landslide-dammed lakes and downstream flooding. Earthquake-induced geohazards occurred mainly along
the fault zone and decreased sharply with distance from the fault. It can be anticipated that post-earthquake geohazards,
particularly for debris flows, will continue for 5–10 years and even for as long as 20 years. An integrated strategy of continuing
emergency response and economic reconstruction is required. The lesson from Wenchuan Earthquake is that the resulted geohazards
may appear in large number in active fault regions. A plan for geohazard prevention in the earthquake-active mountainous areas
is needed in advance. 相似文献
130.
Long runout landslides involve a massive amount of energy and can be extremely hazardous owing to their long movement distance, high mobility and strong destructive power. Numerical methods have been widely used to predict the landslide runout but a fundamental problem remained is how to determine the reliable numerical parameters. This study proposes a framework to predict the runout of potential landslides through multi-source data collaboration and numerical analysis of historical landslide events. Specifically, for the historical landslide cases, the landslide-induced seismic signal, geophysical surveys, and possible in-situ drone/phone videos (multi-source data collaboration) can validate the numerical results in terms of landslide dynamics and deposit features and help calibrate the numerical (rheological) parameters. Subsequently, the calibrated numerical parameters can be used to numerically predict the runout of potential landslides in the region with a similar geological setting to the recorded events. Application of the runout prediction approach to the 2020 Jiashanying landslide in Guizhou, China gives reasonable results in comparison to the field observations. The numerical parameters are determined from the multi-source data collaboration analysis of a historical case in the region (2019 Shuicheng landslide). The proposed framework for landslide runout prediction can be of great utility for landslide risk assessment and disaster reduction in mountainous regions worldwide. 相似文献