Super typhoon activity over the western North Pacific and its relationship with ENSO     

Fei Huang  Shibin Xu 《中国海洋大学学报(英文版)》2010,9(2):123-128

This paper analyzes the characteristics of super typhoons(STYs)over the western North Pacific(WNP)from 1965 to2005 and describes the seasonal variability of STY activity.The relation between STY activity and the El Nio-Southern Oscillation(ENSO)as well as the possible reason for the influence of the ENSO on STY activity are also investigated.The results showed thatabout one fifth of the tropical cyclones(TCs)over the WNP could reach the rank of STY.Most STYs appeared from July to Novem-ber while there was a highest ratio between number of STYs and total number of TCs in November.Most STYs appeared east of thePhilippine Sea.In El Nio years,affected by sea surface temperature(SST),monsoon trough and weak vertical wind shear,TC for-mation locations shifted eastward and there were more STYs than in La Nia years when the affecting factors changed.  相似文献   

北京西山下苇甸地区青白口系长龙山组沉积相及层序地层研究^*          下载免费PDF全文

张驰  李建安  焦杰伟  丁玥  邵龙义 《古地理学报》2017,19(6):955-964

北京西山下苇甸地区出露良好的青白口系长龙山组,笔者通过实测野外露头剖面以及岩石薄片镜下鉴定,对该组下部沉积相及层序地层进行研究,并对沉积环境演化进行分析。识别出长龙山组下部8种岩石类型有含砾砂岩、羽状交错层理砂岩、丘状交错层理砂岩、波状层理粉砂岩、脉状层理粉砂岩、透镜状层理粉砂岩、碳质泥岩以及水平层理泥岩;并识别出辫状河道、潮坪(潮道)、潮下浅水及潮下深水等沉积相类型,建立该区辫状河—滨岸潮坪沉积模式。进而通过识别长龙山组与其下伏地层之间的区域不整合面和下切谷河道充填砂砾岩底面确定层序界面。其中,初始海泛面以每个砂体之上覆盖的细粒沉积的底面为代表,最大海泛面以厚层碳质泥岩及水平层理泥岩的底面为代表。依据这些关键层序地层界面,将该区长龙山组下部划分为3个层序,每个层序内部进一步划分为低位体系域、海侵体系域以及高位体系域。综合分析表明,京西的长龙山组发育于由燕辽裂陷槽转为华北稳定克拉通的过渡期。  相似文献   

开江—梁平台内海槽东段长兴组白云岩储层沉积-成岩系统研究     

张兵  杨凯  贾雪丽  郑荣才  郭强  文华国 《吉林大学学报(地球科学版)》2017,(6):1631-1641

为了指导部署四川盆地白云岩储层中钻井,在油气钻井岩心观察与描述、野外剖面实测和样品采集的基础上,结合镜下薄片鉴定、X衍射、物性和地球化学特征分析,对开江—梁平台内海槽东段长兴组白云岩储层的沉积-成岩系统进行了深入研究。认为台地边缘生物礁和台地边缘浅滩为最重要的储集相带,颗粒白云岩、生物礁白云岩和晶粒白云岩为最主要的储集层岩性,晶间孔、晶间溶孔和超大溶孔为目的层最有效的储集空间,孔洞缝复合型储层为目的层最优质的储集类型。综合分析认为,长兴组沉积-成岩系统与白云岩储层在时空上具有良好的耦合关系,台地边缘生物礁和台地边缘浅滩相控制了白云岩储层的区域分布范围,而不同成岩系统对储层的贡献程度不同。其中:地层封存卤水与混合热卤水成岩系统是储层形成的基础与关键,地层封存卤水形成低孔低渗的孔隙型Ⅲ类储层,混合热卤水形成中孔中渗的孔洞型Ⅱ类储层;构造热液成岩系统对储层贡献最大,并形成高孔高渗的孔洞缝复合型Ⅰ类优质储层。  相似文献   

Peak Dynamic Pressure on Semi- and Quarter-Circular Breakwaters Under Wave Troughs   总被引：1，自引：0，他引：1  

JIANG Xue-lian  ZOU Qing-ping  SONG Ji-ning 《海洋工程》2017,31(2):151-159

A series of physical tests are conducted to examine the characteristics of the wave loading exerted on circular-front breakwaters by regular waves. It is found that the wave trough instead of wave crest plays a major role in the failure of submerged circular caissons due to seaward sliding. The difference in the behavior of seaward and shoreward horizontal wave forces is explained based on the variations of dynamic pressure with wave parameters. A wave load model is proposed based on a modified first-order solution for the dynamic pressure on submerged circular-front caissons under a wave trough. This wave loading model is very useful for engineering design. Further studies are needed to include model uncertainties in the reliability assessment of the breakwater.  相似文献   

桂西2008年前汛期一次典型大范围暴雨天气过程分析     

卢小丹 《云南地理环境研究》2008,20(Z1):106-109

采用常规气象资料和NCEP再分析资料,对桂西2008年5月29~30日一次大范围暴雨天气过程进行分析。结果发现,活跃的西南季风给桂西上空输送水汽和不稳定能量,是此次暴雨发生的突出特点;南支槽的东移、850hpa切变线南压、地面冷空气南下是暴雨产生的直接影响系统;水汽通量散度表示的水汽辐合区与暴雨中心较为对应,散度场、垂直速度场的相互配置,使暴雨系统加强,K指数、SI指数对暴雨发生有一定指示意义。  相似文献   

2007年淮河流域致洪暴雨及其中尺度系统特征的分析   总被引：20，自引：9，他引：11  

赵思雄  张立生  孙建华 《气候与环境研究》2007,12(6):713-727

针对2007年6～7月的淮河致洪暴雨,采用NCEP资料、卫星TBB（Temperature of Black Body）资料、地面加密资料和1h的降水资料对此次暴雨过程进行了详细的分析,得到结果如下:1）2007年6～7月主汛期的暴雨带主要位于淮河流域,而不是像通常那样集中在长江中下游。时间长达30余天,超过2003年（持续20余天）。2）整个汛期从6月19日开始至7月26日结束,根据影响系统和雨区分布的不同,可将降水分为3个阶段。其中,第2阶段（6月29日～7月10日）降水最强,影响最大,与梅雨的降水有更多相似。在第2阶段中又有4次降水过程,其中第4次过程（7月7～9日）降水最强,导致10日在王家坝开闸泄洪。3）高纬度的阻塞形势（西阻型）有利于环流的稳定维持和暴雨的持续发生。4）副热带高压稳定在26°N,有利于雨带维持在32°N,另外南海季风涌沿副高西侧将大量水汽输送至淮河流域。5）在阻高和副高之间的西风带上,巴尔喀什湖为低槽区,不断有小股冷空气经我国西北和黄河上游沿偏西路径移至淮河流域,西风槽加深甚至在中国大陆出现切断低压,这在过去淮河暴雨期间不太多见,表明存在明显的中低纬度的相互作用。与此同时,在7月8日高空急流入口区（右侧）与低空急流出口区（左侧）相迭置耦合,非常有利于垂直运动的加强和暴雨的发生。6）在暴雨期间有中尺度低压（扰动）的发生发展,并有与之相关的中尺度云团、雨团甚至更小的中尺度对流系统出现,致使8日寿县24h降水量达262 mm之多。该次强暴雨与淮河流域前期多场强降水形成的高水位“遭遇”,引发了严重的洪水,其影响超过了2003年,成为了1954年以来淮河流域最严重的洪涝。    相似文献   

中国晚寒武世岩相古地理   总被引：20，自引：16，他引：4       下载免费PDF全文

冯增昭  彭勇民  金振奎  鲍志东 《古地理学报》2002,4(3):1-10

本文是《中国早寒武世岩相古地理》和《中国中寒世岩相古地理》的继续。本文的基础是笔者等的华北地区、华南地区和西北地区寒武纪和奥陶纪定量岩相古地理研究及编图的成果。定量,即每个古地理单元的划分都有确切的定量资料和定量图件为依据。在此基础上,结合其他地区的地质资料,全面分析,综合判断,编制出了全国范围的晚寒武世岩相古地理图并撰写出本文。因此,在本文中,华北、华南和西北地区的岩相古地理图及其文字论述是定量的和比较精细的,其他地区的岩相古地理图及其文字论述则是定性的和概略性的。在中国晚寒武世,中寒武世的 “两槽和三台相间分布”的古地理格局依然存在。两槽即天山北山蒙辽吉槽地和昆仑秦岭槽地,三台即准噶尔蒙兴台地、塔里木柴达木华北台地和西藏华南台地。这5个古地理单元的范围与中寒武世的基本上相同,但他们的次级古地理单元的特征则与中寒武世的有所不同或大不相同。  相似文献   

ANALYSES OF THE DYNAMIC EFFECTS ON WINTER CIRCULATION OF THE TWO MAIN MOUNTAINS IN THE NORTHERN HEMISPHERE——Ⅰ.RELATIONSHIP AMONG GENERAL CIRCULATION,TELECONNECTION AND STATIONARY WAVES          下载免费PDF全文

邹晓蕾  叶笃正  吴国雄 《Acta Meteorologica Sinica》1992,(4)

The distribution of troughs and ridges of geopotential height,the teleconnection patterns and the propagation pat-terns of stationary waves are the main features of the January mean geopotential height field at 500hPa.Data analysesand numerical experiments indicate that these three characteristics are associated to one another and closely related tothe mechanical forcing of the Rocky Mountains and Tibetan Plateau.There exists a prominent negative correlation inthe intensity variation between the American trough and the Asian trough at high and middle latitudes.Such negativecorrelation,in connection with the interannual variation of the intensity of the jets in front of the two troughs,leads tothe existence of similar teleconnection patterns in North America and East Asia.On the other hand,the different propa-gation behaviour of quasi-stationary waves downstream of the two main mountains results in a fundamental differencein the distribution of correlation chains in North America and East Asia.  相似文献   

Physical criterion to evaluate seismic activity associated with the seismic cycle of great interplate earthquakes     

Takane Hori  Yoshiyuki Kaneda 《Journal of Seismology》2004,8(2):225-233

A new criterion is introduced to judge if the vicinity of the source region of a great interplate earthquake is in an active period. It is based on the stress change caused by the great earthquake. A region is regarded as being in an active period of seismicity if the occurrence rate of earthquakes on faults in the stress shadow of the great earthquake is significantly higher than in the early stage of the seismic cycle, and if the stressing rate of these faults is sufficiently low. This criterion was applied to the seismicity in the central part of southwest Japan before and after the 1944 Tonankai and 1946 Nankai earthquakes. The results show that before the 1944 Tonankai earthquake, the region was in an active period from at least 1927.The region was in a quiet period for almost50 years after the 1946 Nankai earthquake.Data after 1995 show that the region is once more in an active period of seismicity preceding the next great interplate earthquakes along the Nankai trough,although the total number of earthquakes has not yet significantly increased. Our results indicate that earthquake probability in the central part of southwest Japan will become high in the coming decades until the next great interplate earthquakes along the Nankai trough.  相似文献   

环境流场和“派比安”结构变化对其异常北抬路径影响的诊断分析   总被引：8，自引：0，他引：8  

吴乃庚  林良勋  李天然  黄忠  陈理森 《气象》2007,33(11):9-15

利用NCEP的全球数据同化系统(GDAS)1°×1°分析资料、CIMSS微波亮温资料等,对0606号台风派比安的异常移动路径特征作了诊断分析。结果表明:"派比安"出现的两次异常北抬路径与中纬度西风槽活动、热带西南季风、副热带高压以及热带气旋结构影响密切相关,西风槽槽后经向风活动和台风最大风速中心轴向对台风未来移向有一定的指示意义。  相似文献