排序方式: 共有49条查询结果,搜索用时 15 毫秒
1.
西藏察隅地区的中侏罗统马里组,原划为下泥盆统春节桥组。通过岩石地层层序、岩石组合、沉积地球化学、重矿物特征、与下估地层的接触关系等调查,以及巴通期双壳类化石化组合的新发现,认为均与同一构造带洛隆地区的中侏罗统马里组相同。因此,下泥盆统春节桥组应该废弃。马里组是怒江洋盆地晚三叠世一早侏罗世闭合时,澜沧江弧与三村弧发生强烈磁撞造山,在三村弧后拉张的前隅盆地或山间盆地中沉积的一套中侏罗世红色磨拉石建造。 相似文献
2.
离心模型试验与数值模拟相结合研究采空边坡渐进破坏特性 总被引:1,自引:0,他引:1
以贵州六盘水地区煤层开采为工程背景,采用离心模型试验与数值模拟相结合的方法研究了采空条件下边坡的渐进破坏过程及破坏模式。基于离心模型试验得到了开采过程中边坡的位移场,并采用FLAC~(3D)对离心模型试验过程进行了数值模拟,数值与试验结果得出的边坡位移时程曲线吻合程度较高,塑性区分布与试验点对分析得到的滑裂面破坏过程与路径基本一致。通过对比、融合离心模型试验观测与数值模拟结果,表明贯通坡脚与采空区的滑裂面由下向上形成,且总体发生剪切错动破坏,贯通坡肩与采空区的滑裂面由上至下发生复杂的破坏过程,初始阶段滑裂面发生张拉破坏,中间阶段同时发生张拉与剪切破坏,末尾阶段发生剧烈的剪切滑移破坏。 相似文献
3.
利用热带气旋年鉴、海温和大气环流再分析资料,分析2007年西北太平洋(包括南海)的风暴级以上热带气旋(简称TC)活动状况及海-气条件.结果表明,相对于气候平均值,2007年西北太平洋TC活动的季节峰期推后了约2个月,源地明显偏北,生成点纬度发生了2次明显跃变,年度TC的总体活动较弱,但个体的强度较强,路径以西北行为主,登陆比例偏大.影响上述TC活动特征的一个重要原因是年内ENSO循环的位相使得上半年的大气环流不利因素居多,而下半年大尺度上升运动、热带辐合带均较强,副高偏北、局地垂直风切变较小和对流层低层较强的扰动活动等条件,也十分有利热带气旋活动. 相似文献
4.
西太平洋副热带高压对热带
海温异常响应的研究 总被引:29,自引:5,他引:29
利用多年的观测资料,研究了西太平洋副热带高压对热带海温异常的响应及其相互作用过程。着重研究冬、夏季西太平洋副高对同期及前期不同海域(特别是赤道东、西太平洋以及印度洋海域)海温异常的响应;用SVD方法分析了夏季副热带高压与前冬、前春及同期各月全球海温的最佳耦合模态。在对比研究西太平洋副热带高压异常时其垂直环流变化的基础上,进而研究海气相互作用对副热带高压影响的物理过程。 相似文献
5.
In this paper, 1416 conventional ground-based meteorological
observation stations on the mainland of China were subdivided into
groups of differing spatial density. Data from each subgroup were then
used to analyze variations in the tropical cyclone (TC) precipitation
statistics derived from each subgroup across the mainland of China
(excluding Taiwan, Hong Kong, and Macao), as well as in two regions
(east China and south China) and three provinces (Guangdong, Hainan,
and Jiangxi) between 1981 and 2010. The results showed that for the
mainland of China, total precipitation, mean annual precipitation, mean
daily precipitation, and its spatial distribution were the same
regardless of the spatial density of the stations. However, some minor
differences were evident with respect to precipitation extremes and
their spatial distribution. Overall, there were no significant
variations in the TC precipitation statistics calculated from different
station density schemes for the mainland of China. The regional and
provincial results showed no significant differences in mean daily
precipitation, but this was not the case for the maximum daily
precipitation and torrential rain frequency. The maximum daily
precipitation calculated from the lower-density station data was
slightly less than that based on the higher-density station schemes,
and this effect should be taken into consideration when interpreting
regional climate statistics. The impact of station density on TC
precipitation characteristics was more obvious for Hainan than for
Guangdong or Jiangxi provinces. In addition, the effects were greater
for south China (including Guangxi Zhuang Autonomous region, Guangdong,
and Hainan provinces) than east China (including Shandong, Jiangsu,
Zhejiang, Shanghai, Fujian, Anhui, and Jiangxi provinces). Furthermore,
the analysis proved that the statistical climatic characteristics began
to change significantly when the station spacing was between 40 and 50
km, which are close to the mean spacing for all stations across the
mainland of China. Moreover, TC areal precipitation parameters,
including mean total areal precipitation and mean daily areal
precipitation, also began to change significantly when the spacing was
between 40 and 50 km, and were completely different when it was between
100 and 200 km. 相似文献
6.
正热带气旋位居全球十大自然灾害之首,至今造成全球保险损失金额最高的十大自然灾害事件中有八起与热带气旋有关。西北太平洋(含南海)是全球热带气旋最活跃的海区,中国是全世界受热带气旋影响最严重的国家之一,每年约有7~9个热带气旋登陆在我国人口稠密、经济发达的东南沿海,造成的经济损失随着经济社会发展和人口规模的增长呈日趋加重的态势。我国各级政府及中国气象局始终高度重视防台减灾工作,自1970年代起便建立了全国台风监测预警联 相似文献
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9.
2007年西北太平洋热带气旋定位和预报精度评定 总被引:5,自引:2,他引:3
依据<台风业务和服务规定>分析2007年TC业务定位和业务预报精度,结果表明:各方法的平均定位误差均小于25km,强度预报的24小时和48小时近中心最大风速平均误差为3~7m·s-1和5~11m·s-1,均与往年相当;综合预报的24小时和48小时路径平均距离误差分别为129.8km和215.0km.虽然路径数值预报的能力仍然不能与综合预报相比,但是多模式集成方法相对于综合预报有正技巧,说明这类方法可能成为改善路径预报的途径之一.强度预报的主要参考仍然是统计类预报方法. 相似文献
10.
在西藏1:20万松冷幅,竹瓦根幅区域地质调查中,对左贡县桂亚拉地区发现的岫玉矿的地质特征,矿床特征,岩石,矿物和地球化学特征研究表明,雄恩错组的白云岩受岩浆热液作用形成的岫玉,为研究西藏非金属矿床成矿规律和构造演化及寻找玉石提供了新的基础资料,对岫玉与致密块状质纯的白云岩资源提出了综合开发利用的建议。 相似文献