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51.
52.
A CLIMATOLOGY OF EXTRATROPICAL TRANSITION OF TROPICAL CYCLONES IN THE WESTERN NORTH PACIFIC 总被引:1,自引:1,他引:0
Based on best-track data and JRA-25 reanalysis, a climatology of western North Pacific extratropical
transition (ET) of tropical cyclone (TC) is presented in this paper. It was found that 35% (318 out of 912) of all
TCs underwent ET during 1979–2008. The warm-season (June through September) ETs account for 64% of all ET events
with the most occurrence in September. The area 120°E–150°E and 20°N–40°N is the most favorable region for ET
onsets in western North Pacific. The TCs experience ET at latitudes 30°N–40°N and have the greatest intensity in
contrast to other latitude bands. The distribution of ET onset locations shows obviously meridional migration in
different seasons. A cyclone phase space (CPS) method was used to analyze the TC evolution during ET. Except for
some cases of abnormal ET at relatively high latitudes, typical phase evolution paths—along which TC firstly
showed thermal asymmetry and an upper-level cold core and then lost its low-level warm core—can be used to
describe the main features of ET processes in western North Pacific. Some seasonal variations of ET evolution paths
in CPS were also found at low latitudes south of 15°N, which suggests different ET onset mechanisms there. Further
composite analysis concluded that warm-season ETs have generally two types of evolutions, but only one type in cold
season (October through next May). The first type of warm-season ETs has less baroclinicity due to long distance
between the TC and upper-level mid-latitude system. However, significant interactions between a mid-latitude upper
-level trough and TC, of either approaching or being absorbed into the trough, and TC’s relations with downstream
and upstream upper-level jets, are the fingerprints for both a second type of warm-season ETs and almost all the
cold-season ETs. For each type of ETs, detailed structural characteristics as well as precipitation distribution
are illustrated by latitude. 相似文献
53.
鄂尔多斯盆地靖边气田马五1~4亚段属于陆表海蒸发碳酸盐潮坪相。潮上带(含)石膏结核白云岩和潮间带上部的含石膏晶模白云岩最有利于形成储层。马五1-4亚段碳酸盐岩经历了复杂的成岩作用,准同生期白云石化和膏化作用奠定了储层的物质基础;表生岩溶期选择性溶解作用构筑了储层的轮廓;埋藏期溶解作用和各种矿物充填作用,决定早期溶孔能否保存和储层最终状况。引入“负胶结物孔隙度”概念,更直观地反映了沉积作用对马五1-4亚段储层发育的控制作用。将沉积微相和成岩相研究有机地结合在一起,以简约的方式,用一套数字组合符号半定量地表达沉积微相和成岩相,在开发区块储层评价和预测上获得了良好效果。 相似文献
54.
提出了一种用单片机STC89C52及SJA1000总线控制器组成CAN总线智能节点的设计方案,给出了硬件电路,并详细介绍了SJA1000初始化、接收及发送数据程序的框图及程序设计.设计中程序均已通过调试,介绍的设计方法易于掌握且具有较强的灵活性和通用性,方便使用者学习和掌握. 相似文献
55.
渤中25-1地区油气运移的输导通道及其示踪分析 总被引:1,自引:0,他引:1
渤中25-1地区是渤中坳陷重要的含油气区,具有复杂的构造演化与沉积充填史,输导通道一直是该地区成藏动力学研究的关键.采取宏观与微观相结合的研究思路,在理清研究区构造演化、沉积充填及其油气地质特征的基础上,讨论了油气运移的输导通道并对其进行了示踪分析,进而总结了该区的油气成藏模式.研究表明,长期继承性活动的基底断层是油气垂向运移的主输导通道,原油性质及地层水化学特征证实了断层的输导作用.上新统明化镇组和渐新统沙河街组渗透性储层是油气侧向运移的主要通道.沙河街组油藏具有自源压控侧向运移成藏的特点,明化镇组油藏具有它源断控垂向运移成藏的特点. 相似文献
56.
北祁连山寒山金矿成矿时代讨论 总被引:6,自引:1,他引:6
寒山大型金矿是近年来在北祁连山西段发现的与基性火山岩有关的构造蚀变岩型金矿.作者利用Rb-Sr同位素方法测得寒山金矿的成矿时代为339 Ma,属华力西期.指出寒山金矿的成矿时代应为(303~339)Ma,有多期热液叠加,多期成矿作用.因此,作者认为寒山金矿的热液很可能是青山斜长花岗岩(370±25Ma)、寒山辉长岩(347.1±6.4Ma)共同提供的.由于该区有较多的中酸性岩体存在,现成矿时代的确定对于该区在寻找华力西期-加里东晚期蚀变岩型金矿具有重要意义. 相似文献
57.
2005年在西藏达孜县羌堆铜矿区进行了1/2.5万的路线土壤测量(40 km2),路线土壤测量省力经济,适用于地形复杂、植被发育的通行困难地区;根据土壤测量的地化异常特征推断了3条断裂、3个半隐伏-隐伏的斑岩体,发现12处地化异常,其中11-A为已知矿致异常,8-A,4-B,6-A,9-A异常分别为寻找斑岩型铜矿、构造蚀变岩型金矿的良好靶区,可安排地质物探综合普查. 相似文献
58.
A numerical model for the computation of the wind field,air temperature and humidity in the atmospheric boundary layer (ABL) including the urbancanopy was developed for urban climate simulation. The governing equations of the modelare derived by applying ensemble and spatial averages to the Navier–Stokes equation, continuityequation and equations for heat and water vapour transfer in the air. With the spatial averagingprocedure, effects of buildings and other urban structures in the urban canopy can be accounted for byintroducing an effective volume function, defined as the ratio between the volume of air in acomputational mesh over the total volume of the mesh. The improved k - model accounts for the anisotropyof the turbulence field under density stratification. In the improved k - model, the transportof momentum and heat in the vertical direction under density stratification is evaluated based onthe assumption of a near-equilibrium shear flow where transport effects on the stresses andheat fluxes are negligible. The heating processes at surfaces of buildings and ground are alsomodelled. The comparison of the computational results obtained with the present modeland existing observational data and numerical models shows that the present model is capableof predicting the structure of turbulence in the urban canopy layer under density stratification.Numerical experiments with the new model show that the flow behaviour of the air in the urbancanopy layer is strongly affected by the existence of buildings and density stratification. 相似文献
59.
当前人们普遍认为地球生物史上最早的后生动物是伊迪卡拉动物群,由软躯印痕化石组成,多数学者认为是刺胞动物,年代约6 ̄7亿年前,而多门类骨骼化石的出现则是寒武系底界的标志。震旦晚期虽有少量报道,但其层位不低于陆山陀组。但是,陈耳化石因其年代古老(12亿年)而又显示多样的贝壳或骨骼的性质,学术界反映谨慎,认为将其归为可疑化石较为可靠。笔者从化石的保存特征、形态组合面貌、有机与无机成分分析和结构构造研究等 相似文献
60.
The triterpenoid hydrocarbons of some West Australian shales have been examined by GC-MS. In addition to the common 17α(H),21β(H)-hopanes, 17β(H),21β(H)-hopanes and 17β(H),21α(H)-moretanes, 28,30-bisnorhopane, 25,28,30-trisnorhopane and 25-norhopanes were identified in the organic extracts. In contrast, pyrolysates of the solvent-extracted sediments contained only the common hopane and moretane series, indicating that 28,30-bisnorhopane, 25,28,30-trisnorhopane and 25-norhopanes are not bonded to kerogen, but rather are present in the sediments as free hydrocarbons. 相似文献