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1.
黄维东 《水文》2019,39(6):27-33
选取甘肃省境内11个典型小流域的水文站实测资料,在分析资料可靠性、一致性、代表性及暴雨洪水特性的基础上,综合利用水文学、数理统计学等理论和方法,建立了小流域最大暴雨量-暴雨历时关系模型、最大洪峰流量-流域特征关系模型。结果表明:各时段最大暴雨量较大值主要分布在泾河流域和嘉陵江流域东南部,较小值主要分布在渭河流域、洮河流域、嘉陵江流域的北峪河;绘制了各代表站最大暴雨量-暴雨历时关系曲线,嘉陵江流域以90min为转折点,其他流域均以180min为转折点,小于转折点时,暴雨量随暴雨历时增长而急剧增加,大于转折点后,变化趋于平缓稳定。重点选取危害较大、难以防范的330场次短历时暴雨洪水,建立各小流域暴雨洪水概化模型,短历时洪水发生时间很短,洪水起涨时间约2~5h,洪峰出现时间约5~7h。研究典型小流域水文要素变化规律,分析局地短历时暴雨洪水特性,并模拟其变化过程,对区域抗旱防汛减灾、水资源管理、小流域治理及生态环境保护具有重要意义。  相似文献   

2.
田茂连 《水文》2004,24(3):58-61
贝江流域是广西境内最大暴雨高值区的暴雨中心,该流域的降水量、暴雨强度、暴雨持续历时等多项水文特征值指标均居广西之最,在珠江流域也名列前茅。结合该流域的自然地理概况,从降水、蒸发、洪水、径流等方面分析了该流域的水文特性,探讨了各水文要素的变化规律。  相似文献   

3.
"98·7"陕南宽坪特大暴雨调查分析   总被引:4,自引:0,他引:4  
刘平贵  王建卿  庞雷 《水文》2002,22(2):53-57
“98·7”陕南宽坪特大暴雨降雨强度之大为历史罕见,暴雨中心最大点雨量超过1300mm,降雨历时6~7小时,超过迄今同历时降雨量的世界最大纪录。对这场暴雨进行了调查,对暴雨特性和成因进行了分析,雨洪对照对暴雨进行了合理性检查,得到了合理、可信的科学数据。  相似文献   

4.
何秋明 《地下水》2018,(5):177-178,198
甘肃省属于典型的短历时暴雨多发区域,因暴雨以及强降雨所造成的洪涝灾害严重,并且在水文循环系统中暴雨作为活跃性因子对系统影响显著。据此,本文在详细分析了下垫面对暴雨影响作用的基础上,分别对黄河干流区、长江、渭河、泾河以及境内嘉陵江水系的10 min、60 min、6 h、24 h的4种时段的雨量级别分布规律进行研究,通过对不同时段的雨量发生时间和地点进行研究分析探讨了不同曲线转折点的暴雨衰减指数n的变化规律。  相似文献   

5.
甘肃省时段暴雨量随高程变化规律分析   总被引:1,自引:2,他引:1  
甘肃是一个暴雨多发的省份,通过介绍与暴雨关系密切的甘肃自然地理概况,选用甘肃境内雨量站的长系列观测资料,在统计10min、60min、6h、24h、3d5个时段多年平均时段最大暴雨量的基础上.选择了三个代表性流域一黑河流域、祖厉河流域和洮河流域研究了5个时段的暴雨量随高程的变化而变化的规律。对于认识甘肃暴雨随高程的变化规律,了解甘肃暴雨特性,指导暴雨观测与山区水资源量计算等具有重要意义。  相似文献   

6.
各历时实测和调查最大点雨量纪录(通常用雨深~历时关系表示)提供了各地点实际出现的雨量极值,对点的设计暴雨和可能最大暴雨的估算有着良好的作用。美国利用700多次暴雨资料制作了暴雨最大时面深纪录。我们利用1977年以来各省、市、自治区暴雨分析小组和水电部流域机构、设计院等单位分析计算的  相似文献   

7.
利用海河流域实测和调查年最大点暴雨、实测大面积暴雨和气象等资料,分析了年极端点暴雨的季节变化、特征和地区分布、大面积暴雨特征以及形成极端暴雨的天气成因,揭示了极端暴雨发生的基本规律。结果表明,流域暴雨9成以上集中在7~8月,极端暴雨7成高度集中在7月下旬到8月上旬;极端暴雨集中分布在太行山~燕山山脉的迎风山区;短历时小面积极端暴雨则分布在高原区;极端暴雨的年际变率迎风山区最大,平原和高原区较小;流域性极端暴雨高空环流多为经向型,通过中纬度西风槽、副热带高压或台风等天气系统以及迎风山区地形抬升作用共同造成。  相似文献   

8.
编制适用于不同历时的综合暴雨公式是协调城市管网排水与区域防洪治涝的重要基础。选用上海市代表雨量站徐家汇站65 a实测雨量资料,建立不同重现期暴雨强度与历时关系,解析暴雨衰减规律,编制单一重现期暴雨公式,结合雨力公式推求适用不同重现期的长历时综合暴雨公式,并推导出暴雨重现期公式。结果表明:不同重现期1~24 h历时暴雨强度均以0.74的衰减指数衰减,据此推求的长历时综合暴雨公式可计算1~24 h任意历时、2~100 a任意重现期的设计暴雨,且平均相对和平均绝对均方根误差分别为1.9%和0.009 mm/min,符合规范要求;暴雨重现期公式可估算1~24 h历时内任意场次暴雨的重现期,高效地服务于城市洪涝防治决策。成果已纳入上海市治涝地方标准,对其他城市具有参考价值。  相似文献   

9.
采用山东省暴雨系列较长的291~904处雨量站、历时为10min~3 d、8 710~39 366站年的暴雨资料,按照统一的计算方法分析计算了全省5种历时点暴雨统计参数;在此基础上,采用地区综合的方法求得各历时全省5个暴雨分区的偏倍比,分析了山东省暴雨偏倍比随地区和历时的变化规律;同时,利用线性相关分析探讨了多个影响因子.  相似文献   

10.
刘思敏  王浩  严登华  秦天玲 《冰川冻土》2016,38(5):1264-1272
全球气候变化对暴雨洪涝等极端天气事件的发生产生了显著影响,识别气候变化背景下暴雨事件的时空变化特征是暴雨洪涝灾害综合应对的关键.以淮河流域为研究区,基于流域内229个气象站点1950-2012年的实测逐小时降水数据,遵循淮河流域实际情况对暴雨事件进行场次划分,并以此作为基础统计单元,借助地理信息系统平台,运用统计学方法并结合气象学理论,以场次暴雨事件开始时间、达到雨强峰值历时、场次平均暴雨历时及暴雨事件发生频次4个指标分析不同年代背景下淮河流域场次暴雨事件发生的过程变化及时空演变特征.结果表明:在气候变化的背景下,场次暴雨发生时间呈现宽幅化和极值化的变化趋势,暴雨发生时间出现了后移和双峰化的特征;暴雨历时及到达雨强峰值历时均呈现增加趋势,整个流域场次暴雨事件在1990s-2000s进入一个增加时期;全球性的气候变化使流域内暴雨事件发生的频次不断增加,历时不断增大,长历时高频次特征明显,尤其是近20 a来,淮河流域暴雨事件高发区域呈现出从流域部分地区向全流域扩张的趋势.  相似文献   

11.
International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen.  相似文献   

12.
It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T 3 = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″.  相似文献   

13.
14.
Chronological analyses of correlations between certain global repeating events (mass extinctions of marine organisms, meteorite impacts, and flashes in the frequency of geomagnetic reversals) during the Phanerozoic Eon and the motion of the solar system in the Galaxy are presented for five rotationally symmetrical models for the regular Galactic gravitational field. Thirteen of sixteen mass-extinction events can be described by a repetition interval of 183±3 million years. This is in agreement with the anomalistic period (interval between two subsequent passages of the Sun through the apocenter of its Galactic orbit) in the model of Allen and Martos. The positions of the minima and maxima in Gaussian functions approximating the frequency distribution for geomagnetic reversals also agree with the times of passage of the Sun through the apocenter and pericenter, respectively, of its Galactic orbit in this model. The maximum in the distribution of the deviations of the dates of mass extinctions from the nearest dates of impacts of large, crater-forming bodies is close to zero, providing evidence that many such events are correlated. As a rule, extinctions follow impact events. The impacts of large bodies have occurred most often when the solar system passes through the Galactic plane, while mass extinctions occur more often at some distance from the Galactic plane (about 40 pc). As a rule, intervals of increases in the frequency of geomagnetic reversals coincide with dates of impacts of large bodies. At the same time, these intervals do not show a clear correlation with the dates of mass extinctions. The intensity of mass extinctions, like the energy released by impacts, is consistently higher in periods when the Sun is moving from the apocenter toward the pericenter of its orbit, than when it is moving from the pericenter toward the apocenter. Thus, there is evidence for a variety of relationships between repeating global events in the Phanerozoic and the motion of the Sun in the Galaxy. Long-period variations in the frequency of geomagnetic reversals are correlated with the orbital motion of the Sun, and increases in the frequency of geomagnetic reversals are correlated with impacts. Mass extinctions are correlated with the impacts of large bodies, whose motions may have been perturbed by clouds of interstellar material concentrated toward the Galactic plane and by the shock front associated with the Perseus spiral arm, through which the solar system passes. The velocity of the Sun relative to the spiral pattern is estimated.  相似文献   

15.
从榴辉岩与围岩的关系论苏鲁榴辉岩的形成与折返   总被引:4,自引:1,他引:4       下载免费PDF全文
位于华北和扬子两板块碰撞带中的苏鲁榴辉岩形成的温压条件不但是超高压,而且是高温。榴辉岩的PTt轨迹表明其为陆-陆磁撞俯冲带的产物。榴辉岩的区域性围岩花岗质片麻岩为新元古代同碰撞期花岗岩,榴辉岩及其他直接围岩皆呈包体存在于其中,并见新元古代花岗岩呈脉状侵入榴辉岩包体中。区域性围岩新元古代花岗岩的锆石中发现有柯石英、绿辉石等包裹体,表明新元古代花岗岩的组成物质也经受过超高压变质作用,且榴辉岩与围岩新元古代花岗岩的锆石U-Pb体系同位素年龄基本相同。但新元古代花岗岩所记录的变质作用和变形作用期次(或阶段)却少于榴辉岩。椐上述可得如下推断:超高压榴辉岩与新元古代花岗岩岩浆是同时在碰撞带底部(俯冲板块前部)形成的;榴辉岩的第一折返阶段是由新元古代花岗岩岩浆携带上升的,其第二折返阶段是和新元古代花岗岩一起由逆冲及区域性隆起而上升,遭受剥蚀。  相似文献   

16.
某高速公路下伏煤矿采空区稳定性分析   总被引:10,自引:0,他引:10  
在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上, 进行了稳定性数值模拟分析, 定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明: 该煤矿采空区的变形尚未完成, 对拟建的高速公路将产生很大的危害, 必须采取相应的工程治理措施。   相似文献   

17.
18.
摩擦桩基桩土间极限摩阻力取值问题探讨   总被引:1,自引:0,他引:1  
陈银生 《世界地质》1999,18(1):54-59
通过对广珠东线高速公路横沥大桥的试桩及土体的工程地质条件分析,总结出影响摩擦桩基桩土间极限摩阻力取值的一般问题以及解决问题的方法和措施。  相似文献   

19.
In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.  相似文献   

20.
The structure of the eastern Pyrenees consists mainly of south-directed thrusts involving basement and cover rocks. An antiformal stack developed by the piling up of basement thrust sheets which outcrop in the Axial zone. These structures account for a thin-skinned thrust model rather than a vertical fault model in which the Axial zone would be essentially autochthonous, and the North-Pyrenean fault the axial plane of a fan thrust system. New data from the Eastern Pyrenees and the thin-skinned model suggest that(1) the structure east of the Pedraforca nappe is similar to that of the Central Pyrenees; (2) the cover rocks of the South-Pyrenean units and of the Axial zone-after restoration—built up a northwards-thickening prism consistent with the existence of a unique Pyrenean sedimentary basin during Mesozoic time; (3) the Axial zone is only a complex antiformal stack developed as a part of South-Pyrenean system related to the Paleogene thrusting-tectonics. The Axial zone palaeogeographic area had no special meaning during Mesozoic time.  相似文献   

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