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1.
渤海、黄海沿岸主要港湾假潮的基本特征   总被引:3,自引:0,他引:3  
基于港湾假潮振动的基本原理,从渤海、黄海沿岸20个验潮站多年水位自记曲线资料获取假潮参数,并对其做了统计分析,给出了假潮的统计特征,还讨论了假潮形成的初步原因。结果表明,该海域主要港湾假潮出现具有明显的局地性、季节性和年际变化;夏季是大振幅假潮(振幅^1)≥80cm)的多发期,冬季基本上不出现;龙口港湾的大振幅假潮最为突出,最大振幅可达293cm;气压和风速、风向突变的良好配合,是发生大振幅假潮的主要原因。  相似文献   

2.
龙口港的假潮及成因探讨   总被引:1,自引:0,他引:1  
利用 23 a (1964—1986 年)的假潮资料,讨论了龙口港假潮的振幅、频率、周期和持续时间等;给出了导致假潮的各种天气形势和风场;分析了不同气象要素对假潮的贡献;探讨了大和特大振幅假潮的成因。分析结果表明:风场变化是导致龙口港假潮的直接原因;100 cm 左右和 >150 cm 的大和特大振幅假潮,是龙口港特殊地理环境、港湾及附近大范围海域骤猛的向港爆发性大风尤其强雷暴大风涌水在港内骤然积聚和海水惯性振荡的综合结果,该假潮具有较大危害性。  相似文献   

3.
分离龙口港假潮的滤波器   总被引:1,自引:1,他引:1  
一、引言在湖沼或海湾中,水表面往往存在几厘米或几十厘米甚至更大的高度、周期在几分钟到一二个小时左右的振动,人们称这种运动为副振动或假潮。港湾假潮的出现,特别是大振幅的假潮现象,不仅给国民经济带来损失,而且给船只航行和潮汐预报带来困难。为此假潮这一自然现象早已被人们注意,并进行大量研究。  相似文献   

4.
根据山东半岛沿岸12 个验潮站的水位资料曲线,摘取了各站的假潮参数(周期、振幅、延时和峰值出现时刻),并对该区域沿岸大振幅假潮变化做了统计分析,给出了假潮的基本特征——发生频率、月出现率、振动周期、延时和峰值出现的时刻;分析了假潮周期的谱型,最后还讨论了大振幅假潮形成的初步原因。  相似文献   

5.
黄、渤海沿岸港湾的假潮及成因探讨   总被引:1,自引:0,他引:1  
本文通过对日照港以北黄、渤海沿岸18个港湾8~27年假潮资料的分析,给出了不同区域港湾的假潮状况和成因.在该区域只有龙口港可时常发生100cm左右的大振幅假潮和>150cm甚至>300cm的特大振幅假潮,属假潮特别严重和唯一发生较大危害性假潮港湾;其余分属假潮相对较重、较轻和无假潮港湾,其假潮基本不具危害性或无危害性.分析结果表明其突然而剧烈的风场变化是导致各港湾假潮的直接原因,地理环境差异是造成港湾假潮强弱的关键因素;龙口港100cm左右和>1 50cm的大和特大振幅假潮,是其特殊地理环境、港湾及附近大范围海域骤猛的向港爆发性大风,尤其强雷暴大风涌水在港内骤然积聚和海水惯性振荡的综合结果.  相似文献   

6.
山东半岛沿岸的大振幅假潮   总被引:6,自引:0,他引:6  
根据山东半岛沿岸12个验潮站的水位资料曲线,摘取了各站的假潮参数,并对该区域沿岸大振幅假潮变化做了统计分析,给出了假潮的基本特征-发生频率,月出现率,振动周期,延时和峰值出现的时刻,分析了假潮周期的谱型,最后还讨论了大振幅假潮形成的初步原因。  相似文献   

7.
渤海、黄海沿岸主要港湾大振幅假潮成因的天气学分析   总被引:1,自引:0,他引:1  
对渤海、黄海主要港湾发生的振幅大于50cm(龙口港湾取振幅大于80cm)的65次假潮过程与地面天气图进行对比分析,着重分析了伴随大振幅假潮过程的天气形势.分析结果表明:(1)龙口港湾22次大振幅假潮中有19次与雷暴天气(其中有3次伴随有飑线,1次还伴有龙卷)有关,2次与大风天气有关,1次由外海雷暴引起;因此得出雷暴、飑线是引起大振幅假潮的主要原因;雷暴强弱和持续时间长短变化,导致假潮振幅大小及持续时间长短变化;雷暴的季节变化引起大振幅假潮的季节变化;雷暴发生的局地性导致假潮出现的局地性;雷暴传播方向的不同引起大振幅假潮的周期不同.(2)北方气旋型和江淮气旋及西南倒槽型这两种天气类型有利于产生雷暴,并导致大振幅假潮的发生.这两类型分别占62个例的468%和177%.  相似文献   

8.
山东半岛两港湾假潮的基本特征   总被引:2,自引:0,他引:2  
本文根据1970~1996年某验潮站(1)和1964~1995年某验潮站(2)水位自记曲线资料,分析了这两个港湾假潮(振幅大于20cm)的基本特征,给出了假潮出现的频数、周期、延时和峰值出现的时刻,还讨论了假潮的类型及成因。  相似文献   

9.
大连老虎滩澳的大振幅假潮   总被引:3,自引:0,他引:3  
潮汐周期以外的大振幅水位波动(即大振幅假潮),在老虎滩澳时有发生。老虎滩澳位于大连湾侧,是一半封闭深度较浅的三角形小海湾(图1).验潮站位于湾的左岸,距湾顶约1km,水深2.8m.据统计,1980~1994年15年间出现波高大于20cm的假潮共61次。波高超过40cm的为12次。较大振幅事件发生在1994年7月3日,其最大波高为91cm,谱分析显着周期为10min.类似这种小海湾的大振幅假潮在世界其他港湾也经常观测到。其中,以中国的龙口港、日本的长崎港和巴利亚里群岛西岸的锡尤达德拉(Ciu-tadella)港发生的大振幅假潮最为突出。  相似文献   

10.
小长山港内港湾假潮变化的基本特征   总被引:3,自引:0,他引:3  
本文给出了该港湾假潮振幅〉20cm出现的频数,假潮的周期和延时,还讨论了假潮变化的成因。  相似文献   

11.
Characteristics of seiches in Onagawa Bay are investigated on the basis of observations at the bay head, Konorihama, from May 1972 to May 1973 and at the outside of the bay, Enoshima during the same period. At Konorihama seiches with the double amplitude of 7 to 11 cm occurred most frequently (63 percent of the total samples) and the maximum reached 31 cm. Short-time spectral analyses indicate that the periods of the spectral peaks shift considerably with the lapse of time, and that the location of the nodal line near the bay mouth moves offshore and inshore of Enoshima. The cause of these phenomena seems to be attributed to the change of incident angle of waves coming from the open sea to excite seiches. Amplitudes of the fundamental and of the lateral modes of seiches increase or decrease alternately with time, suggesting the energy transfer between these modes. Bay oscillations induced by remarkable atmospheric pressure-waves were observed. However, the amplitudes of the oscillations were within a few centimeters and dissipated in a few hours.  相似文献   

12.
The variations in the free surface of Lake Baikal at three stations (Bol’shie Koty, Listvyanka, and Baikal’sk) are measured. A modern recording method and an advanced technique of record processing are used. Based on 1-year-long observation data, the amplitudes of seiche oscillations and their seasonal changes are analyzed. It is found, in particular, that 67-min seiches are manifested in different seasons. Numerical calculations of seiches in Lake Baikal are made with the use of up-to-date bathymetric data on one-dimensional, plan, and spherical models. Spatial structures of oscillations with periods of 277, 152, 84, 67, and 59 min, corresponding to the well-expressed peaks of power spectral density, are studied. It is shown that the first four periods correspond to uninodal, binodal, trinodal, and quadrinodal longitudinal seiche modes of Lake Baikal. The periods of three solutions can correspond to the value of 59 min. The first of them is the seiche of the lake’s South Basin, and two others are characterized by significant amplitude growth in the Small Sea and Chivyrkui Bay.  相似文献   

13.
Large oscillations of water level in Nagasaki Bay are calledAbiki and are most frequently observed in winter. The largestAbiki recorded in the past 20 years at the tide station at Nagasaki occurred on March 31, 1979. Simultaneously, a distinct atmospheric pressure disturbance of solitary type with an amplitude of about 3 mb was recorded at several neighbouring stations in Kyûshû, which indicated the pressure disturbance probably travelled eastward with an average speed of about 110 km h–1.The quantitative relation between this pressure disturbance and notable seiches observed in Nagasaki Bay is examined by means of numerical simulation, and it is confirmed that the exceptionally large range of oscillations in the bay, which reached 278 cm at the tide station, was indeed produced by this travelling pressure disturbance.The leading part of shallow water waves induced by the atmospheric pressure disturbance was amplified up to about 10 cm in amplitude, over the broad continental shelf region off China, because of near resonant coupling to the pressure disturbance. After leaving this continental shelf region, the amplified water wave converged into the shelf region (Gotô Nada) surrounded by the north-western coast of Kyûshû and the Gotô Islands and excited eigenoscillations on the shelf. A train of waves thus formed with a period of about 35 min entered Nagasaki Bay and was resonantly amplified at periods of 36 min and 23 min which are the eigen periods of the bay. Besides resonance, the combined effects of shoaling and reflection inside Nagasaki Bay also enhanced the amplification.  相似文献   

14.
Numerical experiments were performed to explain the observed results of the internal tides in Uchiura Bay. The experiments for the generation of the internal tides in Suruga Bay indicate that the internal tides, generated at the slopes in the bay, are not as large an amplitude as those observed in Uchiura Bay. However, when the semidiurnal internal tides incident through the mouth of Suruga Bay are considered, they are amplified. The amplitude at the head of Uchiura Bay is 6–12 times larger than that at the mouth of Suruga Bay under the summer density structure. Under the fall density structure, the amplitude ratio is approximately 4–6. The amplification of the semidiurnal internal tides in Uchiura Bay is considered to be due to resonance of the longitudinal internal seiche of Uchiura Bay. On the other hand, the calculated diurnal internal tides are not as large as those observed. Therefore, the diurnal internal tides are thought to already have these large amplitudes at the mouth of Suruga Bay. Therefore, from the observations and numerical experiments, it is concluded that the internal tides observed in Uchiura Bay are mostly the internal tides originating from the outer region of Suruga Bay, and the semidiurnal tides are the internal seiche which is resonantly amplified.  相似文献   

15.
Spatial and temporal variations in surface water phytoplankton pigment distribution in the Bay of Bengal were studied during the spring intermonsoon (SpIM, February–April) and the commencement of the summer monsoon (CSM, May–June), using pigment and diagnostic indices. The Prokaryotic pigment index (ProkDP) was dominant at all the oceanic stations whereas the Flagellate pigment index (FlagDP) was dominant at the near coastal stations. However, during the commencement of summer monsoon, an oscillation in the dominance of ProkDP and FlagDP was observed in the central oceanic bay, whereas flagellates and diatoms were dominant at the near coastal stations. This change in pigment pattern is possibly related to the influence of rainfall. Comparison of pigment data with microscopic cell counts indicated a significant relationship between the diatom pigment index (DiatDP) and diatom abundance. However, the relationship between the dinoflagellate pigment index (DinoDP) and dinoflagellate abundance was not significant. Studies coupling pigment composition analysis with microscopic analysis of phytoplankton in natural conditions should thus be a prerequisite in establishing valid biogeochemical and ecosystem models.  相似文献   

16.
太湖表面定振波的数值计算和最大熵谱分析   总被引:1,自引:0,他引:1  
逄勇  濮培民 《海洋与湖沼》1996,27(2):157-162
利用水动力学方程对太湖表面的定振波进行计算,算得定振波周期约为452min,另外,利用1992年8月29-31日在太湖西山观测到的水位资料,采用最大熵谱法,分析太湖表面的定振波,得周期值约为450min。计算和分析的周期值基本吻合,取熵谱分析结果得太湖表面的单节点定振波周期值为450min。  相似文献   

17.
为快速精确监测九龙江口小型有毒赤潮藻的分布,本工作应用实时荧光定量PCR技术检测了2009年春(5月)、夏(8月)、秋(11月)3个季节九龙江口18个站位水样中米氏凯伦藻(Kareniamikimotoi)的密度.这3个季节分别对应九龙江口水域的丰水期、平水期、枯水期.结果表明,在九龙江口水中米氏凯伦藻的检出范围为未检出至2.3×104cells/dm3;其空间分布差异比较大,主要分布在厦门西港海域,其次是在高潮时的海门岛附近海域;海门岛以西水域几乎未监测到该藻的存在,仅5号站位有1个航次检出.米氏凯伦藻密度的季节分布差异也很明显,春、夏季的密度(最高检出值都达到了2.3×104cells/dm3)明显高于秋季的密度(最高检出值仅为5.4×103cells/dm3).本研究结果可为厦门西港以及九龙江口水域赤潮的研究与监测提供参考.同步进行的显微镜镜检技术没有观测到米氏凯伦藻的存在,可见在藻密度较低(低于103cells/dm3)的情况下,实时荧光定量PCR技术较传统镜检技术(检出限一般在103cells/dm3以上)可能更灵敏.该技术特异性好且操作简便,使对大样本的检测具有可行性,为实现沿岸海域赤潮的动态监测和深入研究奠定了基础.  相似文献   

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