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1.
Erich Bäuerle 《Aquatic Sciences - Research Across Boundaries》1994,56(2):145-160
An episode of velocity measurements in the epilimnion at a midlake station in Lake Überlingen and taken from the campaign in October 1972 discloses a uni-nodal Poincaré-type baroclinic mode response with a 4 h period. We discuss the data and interpret it in terms of a two-layered linear wave model on the rotating Earth.
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2.
K.R. Dyer 《Estuarine, Coastal and Shelf Science》1982,15(4):443-457
The salinity fluctuations at an STD near the halocline in Southampton Water have been spectrally analysed. Mixing is shown to commence at a layer Richardson number of about 20. The predominant energy inputs have periods of 7–9 and 3·5–4·5 min. These motions arise from lateral internal seiching and it is considered that they are produced by interaction of the surface seiche with the shallow side of the estuary. The wavelengths of the standing wave are calculated to be about 120 and 60 m respectively, and these compare well with echo-sounding surveys of the elevation of the halocline. 相似文献
3.
用二维数值模式,根据芝罘湾的实测水深和形状,计算了该湾的固有振动周期,与实测资料吻合较好。计算结果同时给出了当节点N=1,2,...,6时,湾内的振幅分布（合波长、波节线分布）,以及纵振动和横振动分布情况。 相似文献
4.
G. Salvadè K. Stocker J. Trösch F. Zamboni 《Aquatic Sciences - Research Across Boundaries》1992,54(3-4):187-204
The hydrodynamic processes in the Lake of Lugano (Lago di Lugano) have been the object of three major measuring campaigns. The first during summer 1979 in the North Basin, the second in the autumn of 1984 in the South Basin and the last in 1989 again in the North Basin. It is expected that analysis of the collected data in conjunction with theoretical concepts will yield conclusive findings on the driving forces and hydrodynamics of the lake. Numerical models have been applied to the lake and the results have been compared to the measurements. Some models calculate the periods and distributions of amplitude, as well as surface velocities and internal seiches. Other models calculate wind-induced water circulation. Evidence is given to the peculiarities of the North Basin and the difficulties related with the depth-width ratio and with its deep chemical stratification. 相似文献
5.
龙口湾是出现假潮比较显著的海湾之一,据统计1972-1981年间,平均每年出现6次40cm以上的振动,1980年9月1日观测到水位振动的最大振幅达293cm,同日的气压波也有7个hPa的起伏.本文用数值模拟的方法,初步探讨了气压扰动和在龙口湾1980年9月1日观测到的假潮之间的定量关系,证实了在龙口湾中出现的大振幅假潮的确是由于移动气压波扰动激起湾外长波,传入湾内发生共振所导致的.直接由气压波扰动很难导致大振幅假潮的发生. 相似文献
6.
Longwave Measurements for the Coast of British Columbia and Improvements to the Tsunami Warning Capability 总被引：1，自引：0，他引：1
A few years ago the Canadian Hydrographic Service initiated a major upgrade toall tide gauges and tsunami stations on the coast of British Columbia (B.C.). Thisprogram was undertaken to address shortcomings of the earlier digital systems andwas driven by concerns about emergency response continuity in the year 2000. By1999, thirteen tide gauge stations had been installed and were operational. Three ofthese stations (Tofino, Winter Harbour, and Langara) were selected for use as tsunamiwarning stations. Several years of continuous, high quality data have now been collectedat these stations and used for analysis of long waves in the tsunami frequency band.Careful examination of these data revealed two weak tsunamis recorded by severalB.C. stations: a distant tsunami of June 23, 2001 generated by the Peru Earthquake(Mw = 8.4), and a local tsunami of October 12, 2001 induced by the Queen Charlotte Earthquake (Mw = 6.3$). Spectral characteristics of these two tsunamis are compared with the spectral characteristics of long waves generated by a strong storm (October, 2000) and of ordinary background oscillations. The topographic admittance functions (frequency responses) constructed for all stations showed that most of them (in particular, Winter Harbour, Tofino, Bamfield, Port Hardy, and Victoria) have strong resonance at periods from 2.5 to 20 min, indicating that these locations are vulnerable to relatively high-frequency tsunamis. The Winter Harbour station also has two strong resonant peaks with periods of 30 and 47 min and with amplification factors of about 7. The estimated source functions show very clear differences between long waves associated with the seismic source (typical periods 10–30 min) and those generated by a storm, which typically have shorter periods and strong energy pumping from high-frequencies due to non-linear interaction of wind waves. 相似文献
7.
Riyad S. Manasrah Fuad A. Al-Horani Mohammad Y. Rasheed Saber A. Al-Rousan Marouf A. Khalaf 《Estuarine, Coastal and Shelf Science》2006,69(3-4):567
This study was focused on analysis of the horizontal and vertical current components with correspondence to tide variation, heat flux, seiches and relative backscatter intensity in coastal waters of the northern Gulf of Aqaba during the summers of 2001–2004. Spectrum analysis has shown eight distinguishable peaks of the tide measurements. In addition to semidiurnal and diurnal barotropic tides, signal periods of 8.13, 5.89–6.32 and 4.06 h were related to shallow water compound and overtides of the principal solar and lunar constituent and to seiches (second and third mode) generated in the Red Sea, whereas seiches of the first mode might enhance the semidiurnal tide signal. The shortest periods of 1.02–1.05, 0.50 and 0.36 h were related to seiches (first, second and third mode, respectively) generated in the Gulf of Aqaba. The spectrum analysis and cross-correlation tests of the horizontal and vertical current components and relative backscatter intensity suggested that the vertical motion at the diurnal period was either due to migration of zooplankton or to water convection. Both of which were of the same order as vertical motion induced by horizontal motions of water particles projected parallel on the bottom gradient line. On the other hand, semidiurnal and diurnal periods detected in the vertical currents were caused by the strong signal in the cross-shore current component, first mode seiches generated from the Red Sea and tide. This could be considered as an indicator of the dominant force influencing the currents, such as winds, thermocline depth, seiches and tidal forcing. A permanent convection during summer is likely to occur in the shallow coastal waters due to relatively high inclined bottom, high evaporation and blowing of dry air, as well as the observed dominance of the downward vertical currents in coastal waters. 相似文献
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9.
Theoretical Analysis of Harbor Resonance in Harbor with An Exponential Bottom Profile 总被引：2，自引：0，他引：2
The general features of oscillations within a rectangular harbor of exponential bottom are investigated analytically. Based on the linear shallow water approximation, analytical solutions for longitudinal oscillations induced by the incident perpendicular wave are obtained by the method of matched asymptotics. The analytic results show that the resonant frequencies are shifted to larger values as the water depth increases and the oscillation amplitudes are enhanced due to the shoaling effect. Owing to the refraction effect, there could be several transverse oscillation modes existing in when the width of the harbor is on the order of the oscillation wavelength. These transverse oscillations are similar to standing edge waves, and there are m node lines in the longshore direction and n node lines running in the offshore direction corresponding to mode (n, m). Furthermore, the transverse eigen frequency is not only related to the width of the harbor, but also to the boundary condition at the backwall and the bottom shape. 相似文献
10.
Generation of Meteorological Tsunamis (Large Amplitude Seiches) Near the Balearic and Kuril Islands 总被引：5，自引：5，他引：0
Extreme atmosphere-induced seiche oscillations occasionally occur in specific inlets and bays of the world ocean causing severe damage to coastal areas, ships and port constructions. Ciutadella inlet (Menorca Island, Western Mediterranean) can be singled out as a place where such large seiches, locally known as rissaga, are quite common. Similar (although weaker) oscillations are also regularly observed in bays of Shikotan Island (South Kuril Islands, northwestern Pacific). Several spectacular events in these regions, identified in the first part of this study (Rabinovich and Monserrat, 1996), are analysed to determine the atmospheric parameters responsible for the generation of large-amplitude seiches. Their generation mechanism was shown to be quite different from that causing ordinary background oscillations. Coincidence of some external factors and certain resonance effects seem to be necessary to produce the destructive waves. In particular, rissaga waves in Ciutadella inlet were found to be related to significant atmospheric disturbances propagating from the southwest, coinciding with the orientation of the inlet, and having a phase speed of about 3 m/s, which is close to the phase speed of long waves offshore from Menorca. Pronounced resonant properties of the inner basin strongly amplify incoming waves in Ciutadella inlet. In contrast, the bays of the northwestern coast of Shikotan Island are protected from normally incident atmosphere-induced waves by the elongated Kunashir Island, hence the whole situation there is not so favorable for the excitation of large seiches. 相似文献