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1.
渤海夏季环流的高分辨率海浪-潮汐-环流耦合模式研究 总被引：2，自引：0，他引：2
The Bohai Sea is a shallow semi-enclosed inner sea with an average depth of 18 m and is located at the west of the northern Yellow Sea. The climatological circulation pattern in summer of the Bohai Sea is studied by using a wave-tide-circulation coupled model. The simulated temperature and the circulation agree with the observation well. The result shows that the circulation pattern of the Bohai Sea is jointly influenced by the tidal residual current, wind and baroclinic current. There exists an obvious density current along the temperature front from the west part of the Liaodong Bay to the offshore area of the Huanghe Estuary. In the Liaodong Bay there exists a clockwise gyre in the area north to the 40°N. While in the area south to the 40°N the circulation shows a two-gyre structure, the flow from the offshore area of the Huanghe Estuary to the Liaodong Bay splits into two branches in the area between 39°N and 40°N. The west branch turns into north-west and forms an anti-clockwise gyre with the south-westward density current off the west of the Liaodong Bay. The east branch turns to the east and forms a clockwise gyre with the flow along the east coast of the Liaodong Bay. The forming mechanism of the circulation is also discussed in this paper. 相似文献
2.
On the basis of a three-dimensional weakly nonliear theory of Lagrangian residual current in the Baroclinic shallow seas, a diagnostic numerical calculation of wind-driven, thermohaline and tide-induced Lagrangian residual current in the Bohai Sea is made. The model involves the Richardson number in the eddy viscosity coefficient, wind, thcrmolialine and tidal effects in the focing terms. The runoff of the Huanghe River and a part of the Huanghai Warm Water coming from the Huanghai Sea through the Bohai Sea Strait is also considered. The velocity-splitting method is adopted. The wind-driven circu lation, thermohaline circulation and the tide-induced Lagrangian residual circulation are also obtained individually and analysed. The dynamics of the three main eddies in the Lagrangian mean circulation is discussed. Finally, the numerical result is partly verified with the observed data. 相似文献
3.
During June 1997 cruise by R/V Science No.l, observations on temporal and spatialvariations of the size-fractionated phytoplankton standing stock and primary production were carried out in the Bohai Sea. The size-fractionated chlorophyll a (Chl a) and primary production, photosynthet-ically available radiation (PAR), as well as the related physico-oceanographic and zooplanktonic parameters were measured at five time-series observation stations representing sub-areas of the sea. Results obtained show that there were the marked features of spatial zonation of Chl a and primary production in the Bohai Sea. The values in the Laizhou Bay, the Liaodong Gulf and the Bohai Gulf were high and showed close relation with tidal fluctuations, i.e. high Chl a concentration occurred during high tide in the Laizhou Bay, and during low tide in the Liaodong Gulf and the Bohai Gulf. In the strait and the central region of the Bohai Sea, the values were relatively low and no relationship with tidal fluctuation could be foun 相似文献
4.
By taking the Yong River for example in this paper, based on the multiple measured data during 1957 to 2009, the change process of runoff, tide feature, tidal wave, tidal influx and sediment transport are analyzed. Then a mathematical model is used to reveal the influence mechanism on hydrodynamic characteristics and sediment transport of the wading engineering groups such as a tide gate, a breakwater, reservoirs, bridges and wharves, which were built in different periods. The results showed the hydrodynamic characteristics and sediment transport of the Yong River changed obviously due to the wading engineering groups. The tide gate induced deformation of the tidal wave, obvious reduction of the tidal influx and weakness of the tidal dynamic, decrease of the sediment yield of flood and ebb tide and channel deposition. The breakwater blocked estuarine entrances, resulting in the change of the tidal current and the reduction of the tidal influx in the estuarine area. The large-scale reservoirs gradually made the decrease of the Yong River runoff. The bridge and wharf groups took up cross-section areas, the cumulative affection of which caused the increase of tidal level in the tidal river. 相似文献
5.
《中国海洋工程》1988,(1)
- According to the statistics of the number and heights of tidal floods occurring in the Yellow River Delta, the northeast gale changed from southeast wind is the main cause of tidal floods in the Yellow River Delta, high waters of both tidal floods of the Yellow River Delta in 1964 and 1969 occurred when the wind setup of Bohai Sea was succeeded by decreasing water level in the north and increasing in the south. The increased water of Bohai Sea concentrated in Laizhou Bay and thus caused the enormous tidal floods. The tidal wave system with the tidal-free point of M2 tide as center in the Yellow River mouth causes 6-hour tidal time difference in the neighborhood of Shenxian Gou. The astronomical spring tides of the south and the west region occur alternately. The tidal -flood caused by the same increased amount of water is distinctly different between the two sides of Shenxian Gou. When the flood occurs in the west side, the south is in safety and vice versa. According to the estimated return period of spring high tide which occurs once in 200 years, a proposal concerning the design of the tidal barrier is that the crest elevation of the barrier originally designed to be 6 m above the average sea level of the Yellow Sea could be decreased to 4.5 meters in the west section, 4 meters in the middle and 5 meters in the south section. Thus the construction cost can be decreased while ensuring safety. 相似文献
6.
Over the past four periods （ 1959--1960, 1982--1983, 1992--1993, and 1998--1999）, the ecosystem of the Bohai Sea changed due to both a significant decrease of river water discharge from the Huanghe River and a reduction of precipitation. The shifts in nutrient chemistry could result in changes in the phytoplankton composition with an increased potential for non-diatom algal blooms. Simple box model was used to estimate the water - mass balance and nutrient budgets for the Bohai Sea. Water budgets indicate that the residual flow changed from out of the Bohai Sea before 1993, but became inflow to the Bohai Sea after then. The nutrient budgets developed indicate that the Bohai Sea was a sink for nutrients except for phosphate in 1959--1960 and 1982-- 1983 and for silicate in 1982--1983. Net water flow transports nutrients out of the Bohai Sea in 1959--1960, 1982--1983 and 1992--1993, but into the sea in 1998--1999 due to climate changes, such as precipitation and subsequent freshwater discharge. The residual fluxes of nutrients are minor relative to atmospheric deposition and riverine inputs. Conversions of phosphate values to carbon by stoichiometric ratios were used to predict that the system was net heterotrophic before 1982--1983 and net autotrophic after then. Nutrient budgets can explain the change of nutrient concentrations in the Bohai Sea except nitrates, which should include the surface runoff. 相似文献
7.
A numerical method is designed to examine the response properties of real sea areas to open ocean forcing. The application of this method to modeling the China’s adjacent seas shows that the Bohai Sea has a highest peak response frequency(PRF) of 1.52 d-1; the northern Yellow Sea has a PRF of 1.69 d-1; the Gyeonggi Bay has a high amplitude gain plateau in the frequency band roughly from 1.7 to 2.7 d-1; the Yellow Sea(including the Gyeonggi Bay), the East China Sea shelf and the Taiwan Strait have a common high amplitude gain band with frequencies around 1.76 to 1.78 d-1 and are shown to be a system that responds to the open ocean forcing in favor of amplifying the waves with frequencies in this band; the Beibu Gulf, the Gulf of Thailand and the South China Sea deep basin have PRFs of 0.91, 1.01 and 0.98 d-1 respectively. In addition, the East China Sea has a Poincare mode PRF of 3.91 d-1. The PRFs of the Bohai Sea, the northern Yellow Sea, the Beibu Gulf and the South China Sea can be explained by a classical quarter(half for the Bohai Sea) wavelength resonance theory. The results show that further investigations are needed for the response dynamics of the Yellow Sea-East China Sea-Taiwan Strait system, the East China Sea Poincare mode, the Taiwan Strait, and the Gulf of Thailand. 相似文献
8.
The results of the suspended material measurement in the Huanghe River Estuary show that the silt movement in the estuary is different during summer and winter. The centric water-mass in Bohai Sea enters the Laizhou Bay, which makes the fresh water occupy the head of Laizhou Bay and prevents the silt from spveading to the sea.The disturbing of wind in winter makes the sediment resuspend which results in the high content of suspended materials in the water. The distribution of suspended materials and salinity in summer indicate that because of its own momentum, the silt from the Huanghe River will go ahead out of the river mouth and the effect of centric water-mass in the middle Bohai Sea is relatively small in summer. The distributions of suspended materials in the mid and bottom layer water during different seasons show that the primary direction of the siltl movement in the estuary is towards NE, whice coincides with the movement of residual current.Our paper also presents the size distribution of suspended materials.According to the data, we consider that the silt from Huanghe River moves mainly in the surface layer and the Huanghe River Estuary belongs to weak mixing estuary. 相似文献
9.
Seasonal variations in tidal harmonic constants are found to be significant in shelf seas and can be represented by adding a series of astrometeorological constituents (AMC) to the astronomical constituents (AC). The relation of AMC and corresponding AC to their resultant constituents (RC) is examined and the seasonal variation of RC is described by modulation ellipses. The values of AMC in the Bohai Sea are calculated and the major features of AMC in the Bohai Sea are analyzed. The dynamic factors which cause AMC are examined by means of numerical experiments. 相似文献
10.
The rise of tidal level in tidal reaches induced by sea-level rise has a large impact on flood control and water supply for the regions around the estuary.This paper focuses on the variations of tidal level response along the tidal reaches in the Yangtze Estuary,as well as the impacts of upstream discharge on tidal level response,due to the sea-level rise of the East China Sea.Based on the Topex/Poseidon altimeter data obtained during the period 1993～2005,a stochastic dynamic analysis was performed and a forecast model was run to predict the sea-level rise of the East China Sea.Two-dimensional hydrodynamic numerical models downscaling from the East China Sea to estuarine areas were implemented to analyze the rise of tidal level along the tidal reaches.In response to the sea-level rise,the tidal wave characteristics change slightly in nearshore areas outside the estuaries,involving the tidal range and the duration of flood and ebb tide.The results show that the rise of tidal level in the tidal reaches due to the sea-level rise has upstream decreasing trends.The step between the stations of Zhangjiagang and Shiyiwei divides the tidal reaches into two parts,in which the tidal level response declines slightly.The rise of tidal level is 1～2.5 mm/a in the upper part,and 4～6 mm/a in the lower part.The stations of Jiangyin and Yanglin,as an example of the upper part and the lower part respectively,are extracted to analyze the impacts of upstream discharge on tidal level response to the sea-level rise.The relation between the rise of tidal level and the upstream discharge can be fitted well with a quadratic function in the upper part.However,the relation is too complicated to be fitted in the lower part because of the tide dominance.For comparison purposes,hourly tidal level observations at the stations of Xuliujing and Yanglin during the period 1993～2009 are adopted.In order to uniform the influence of upstream discharge on tidal level for a certain day each year,the hourly tidal level observations are corrected by the correlation between the increment of tidal level and the increment of daily mean upstream discharge.The rise of annual mean tidal level is evaluated.The resulting rise of tidal level at the stations of Xuliujing and Yanglin is 3.0 mm/a and 6.6 mm/a respectively,close to the rise of 5 mm/a according to the proposed relation between the rise of tidal level and the upstream discharge. 相似文献
11.
An attenuation depth is defined for remote sensing purposes as a depth above which 90% of the arising light leaving the water surface is originated.The deeper the attenuation depth,the more information of water is detectable by remote sensing,then the more precise information of water is extracted.Meanwhile,the attenuation depth is helpful to know water layer (by its thickness) from which remote sensing will be able to extract information.A number of investigators are using the moderate resolution imaging spectroradiometer (or MODIS) for remote sensing of ocean color.It is necessary to have a rough idea of the effective attenuation depth of imagery in each of the spectral bands employed by the MODIS.The attenuation depth is directly determined from MODIS data.Though analyzing the spectral distribution of the attenuation depth on 7 August 2003 and the seasonal variation of the attenuation depth (551 nm) in the Bohai Sea indicated that:the spectral distribution of the attenuation depth for the spectral range between 400 to 700 nm is single-peak curve,and it''s similar and difference in different regions is consistent with other scholars'' results of zoning,moreover,it supports the Bohai Sea is Case 2 water; the maximum attenuation depth shifts toward longer wavelengths,liking the red shift,with increase of turbidity of water,just like the maximum attenuation depth in the outside of the northwest coast of the Bohai Sea and the Bohai Strait is at 531nm,in the central of the Bohai Sea is at 551nm,in the region controlled by the Huanghe (Yellow) River,the region impacted by the old Huanghe River,the western side of the Liaodong Bay and the eastern side of the Liaodong Bay is at 555 nm; the seasonal change of the attenuation depth is the largest in the summer,followed by the fall,and the ranking of winter and spring in different regions is distinct.The attenuation depth in different regions is dissimilar:the order of the attenuation depth in different regions from small to big is the region controlled by the Huanghe River or the eastern side of the Liaodong Bay,the western side of the Liaodong Bay,the region impacted by the old Huanghe River,the central of the Bohai Sea or the outside of the northwest coast of the Bohai Sea,the Bohai Strait (except at 412 nm and 645 nm),in which between the region controlled by the Huanghe River and the eastern side of the Liaodong Bay (and between the central of the Bohai Sea and the outside of the northwest coast of the Bohai Sea) it varies in different seasons and different bands. 相似文献
12.
In this study, we develop a variable-grid global ocean general circulation model(OGCM) with a fine grid(1/6)°covering the area from 20°S–50°N and from 99°–150°E, and use the model to investigate the isopycnal surface circulation in the South China Sea(SCS). The simulated results show four layer structures in vertical: the surface and subsurface circulation of the SCS are characterized by the monsoon driven circulation, with basin-scaled cyclonic gyre in winter and anti-cyclonic gyre in summer. The intermediate layer circulation is opposite to the upper layer, showing anti-cyclonic gyre in winter but cyclonic gyre in summer. The circulation in the deep layer is much weaker in spring and summer, with the maximum velocity speed below 0.6 cm/s. In fall and winter, the SCS deep layer circulation shows strong east boundary current along the west coast of Philippine with the velocity speed at 1.5 m/s, which flows southward in fall and northward in winter. The results have also revealed a fourlayer vertical structure of water exchange through the Luzon Strait. The dynamics of the intermediate and deep circulation are attributed to the monsoon driving and the Luzon Strait transport forcing. 相似文献
13.
北部湾的环流和水团对季节性强迫的响应 总被引：1，自引：1，他引：0
In the past 20 a, the gulf-scale circulation in the Beibu Gulf has been commonly accepted to be driven by a wind stress or density gradient. However, using three sensitive experiments based on a three-dimensional baroclinic model that was verified by observations, the formation mechanisms were revealed： the circula- tion in the northern Beibu Gulf was triggered by the monsoon wind throughout a year; whereas the southern gulf circulation was driven by the monsoon wind and South China Sea （SCS） circulation in winter and sum- mer, respectively. The force of heat flux and tidal harmonics had a strong effect on the circulation strength and range, as well as the local circulation structures, but these factors did not influence the major circulation structure in the Beibu Gulf. On the other hand, the Beibu Gulf Cold Water Mass （BGCWM） would disappear without the force of heat flux because the seasonal thermocline layer was generated by the input of heat so that the vertical mixing between the upper hot water and lower cold water was blocked. In addition, the wind-induced cyclonic gyre in the northern gulf was favorable to the existence of the BGCWM. However, the coverage area of the BGCWM was increased slightly without the force of the tidal harmonics. When the model was driven by the monthly averaged surface forcing, the circulation structure was changed to some extent, and the coverage area of the BGCWM almost extended outwards 100%, implying the circulation and water mass in the Beibu Gulf had strong responses to the temporal resolution of the surface forces. 相似文献
14.
何良彪 《海洋学报(英文版)》1985,4(1):92-98
Analyses of clay mineralogy about 30 surface sediments indicate widespread occurrence of illite, kaolinite, chlorite and montmorillonite throughout the Bohai Sea. Illite is the most abundant mineral, averaging 60%, kaolinite, next to illite, is the most abundant one,averaging 18%. Chlorite and montmorillonite come second, averaging 12% and 10% respectively. The distributive patterns of clay minerals in the surface sediments are closely related to the suspended materials carried into the Bohai Sea, especially to those did by the Huanghe River, and to water dynamics in the area. Based on the distribution, the assemblages and the others of clay minerals, the Bohai Sea can be divided into two clay mineral regions, the Liaodong Gulf region and the Bohai-Laizhou Bay region. 相似文献
15.
This paper deals with numerical modelling of organic pollutant (COD) in the Bohai Sea. One of the main purposes is intended to provide a useful numerical model for predicting the water quality in the Bohai Sea.A two-dimensional advective-dispersion equation and a set of corresponding ADI difference scheme are used. The computations were executed on the computer in a specially designed program IMEP-TD for modelling dispersion of pollutant. From the modelling results, present water quality in the Bohai Sea is, generally speaking, still fine except the areas near the estuaries and inlets where sea water is contaminated. To protect ecosystem in the Bohai Sea, the inflow load should not keep increasing rapidly. 相似文献
16.
Besides seasonal variation, instantaneous variation of thermal layer will occur under the effects of tide, tidal current and wind disturbance. In this study the numerical simulation has been first carried out on fluctuation and undulation of thermal layer under influence of tide (simultaneous input of 8 tidal components). The study reveals the geographic distribution of thermal layer fluctuation in the entire study region and temporal and spatial variations of the undulation in tidal period superposing on the fluctuation. Especially, the wave with large amplitude simulated is consistent with observation in the channal and the sea areas with a convex coastline and complex variation of depth, internal relations of tide, tidal current, residual current as well as the factors such as geography, and the fluctuation of thermal layer is induced by residual current due to unsymmetry which occurs as a result of the tidal movement in lower layer influenced by friction and geography, meanwhile, analysis indicates 相似文献
17.
A numerical study on the impact of tidal waves on the storm surge in the north of Liaodong Bay 总被引：1，自引：0，他引：1
KONG Xiangpeng 《海洋学报(英文版)》2014,33(1):35-41
A storm surge is an abnormal sharp rise or fall in the seawater level produced by the strong wind and low pressure field of an approaching storm system.A storm tide is a water level rise or fall caused by the combined effect of the storm surge and an astronomical tide.The storm surge depends on many factors,such as the tracks of typhoon movement,the intensity of typhoon,the topography of sea area,the amplitude of tidal wave,the period during which the storm surge couples with the tidal wave.When coupling with different parts of a tidal wave,the storm surges caused by a typhoon vary widely.The variation of the storm surges is studied.An once-in-a-century storm surge was caused by Typhoon 7203 at Huludao Port in the north of the Liaodong Bay from July 26th to 27th,1972.The maximum storm surge is about 1.90 m.The wind field and pressure field used in numerical simulations in the research were derived from the historical data of the Typhoon 7203 from July 23rd to 28th,1972.DHI Mike21 is used as the software tools.The whole Bohai Sea is defined as the computational domain.The numerical simulation models are forced with sea levels at water boundaries,that is the tide along the Bohai Straits from July 18th to 29th（2012）.The tide wave and the storm tides caused by the wind field and pressure field mentioned above are calculated in the numerical simulations.The coupling processes of storm surges and tidal waves are simulated in the following way.The first simulation start date and time are 00：00 July 18th,2012; the second simulation start date and time are 03：00 July 18th,2012.There is a three-hour lag between the start date and time of the simulation and that of the former one,the last simulation start date and time are 00：00 July 25th,2012.All the simulations have a same duration of 5 days,which is same as the time length of typhoon data.With the first day and the second day simulation output,which is affected by the initial field,being ignored,only the 3rd to 5th day simulation results are used to study the rules of the storm surges in the north of the Liaodong Bay.In total,57 cases are calculated and analyzed,including the coupling effects between the storm surge and a tidal wave during different tidal durations and on different tidal levels.Based on the results of the 57 numerical examples,the following conclusions are obtained：For the same location,the maximum storm surges are determined by the primary vibration（the storm tide keeps rising quickly） duration and tidal duration.If the primary vibration duration is a part of the flood tidal duration,the maximum storm surge is lower（1.01,1.05 and 1.37 m at the Huludao Port,the Daling Estuary and the Liaohe Estuary respectively）.If the primary vibration duration is a part of the ebb tidal duration,the maximum storm surge is higher（1.92,2.05 and 2.80 m at the Huludao Port,the Daling Estuary and the Liaohe Estuary respectively）.In the mean time,the sea level restrains the growth of storm surges.The hour of the highest storm tide has a margin of error of plus or minus 80 min,comparing the high water hour of the astronomical tide,in the north of the Liaodong Bay. 相似文献
18.
The Atlantic inflow in the Fram Strait(78°50′N) has synoptic scale variability based on an array of moorings over the period of 1998–2010. The synoptic scale variability of Atlantic inflow, whose significant cycle is 3–16 d, occurs mainly in winter and spring(from January to April) and is related with polar lows in the Barents Sea. On the synoptic scale, the enhancement(weakening) of Atlantic inflow in the Fram Strait is accompanied by less(more)polar lows in the Barents Sea. Wind stress curl induced by polar lows in the Barents Sea causes Ekman-transport,leads to decrease of sea surface height in the Barents Sea, due to geostrophic adjustment, further induces a cyclonic circulation anomaly around the Barents Sea, and causes the weakening of the Atlantic inflow in the Fram Strait. Our results highlight the importance of polar lows in forcing the Atlantic inflow in the Fram Strait and can help us to further understand the effect of Atlantic warm water on the change of the Arctic Ocean. 相似文献
19.
Relationships Between Tidal Prism and Throat Area of Tidal Inlets Along Yellow Sea and Bohai Sea Coasts 总被引：2，自引：0，他引：2
Zhang Renshun Wang Yaping P
rofessor Dept. of Geography Nanjing Normal University Nanjing
Lecturer Nanjing Normal University Nanjing 《中国海洋工程》1996,(2)
The relationship between P (spring tidal prism) and A (throat area below mean sea level) is statistically analysed in terms of 29 tidal inlets or bays along the Huanghai Sea (Yellow Sea) and Bohai Sea coasts. For 15 of these tidal inlets, the best regression equation is A(km2) = 0.845 />(km3)1.20. The analysis shows that C and n are little different from those in the P-A relationship for the inlets of the South China Sea and East China Sea coasts. It is noted that the relationship between P and A is unstable because of the difference in sediment abundance. The study shows that a united P-A relationship can be obtained for the tidal inlets of lagoon type and bay-drowned-valley type, not containing some half-circle shape bays which confront deep water. These half-circle bays do not belong to tidal inlets because they do not have enough sediment abundance and are fairly open. 相似文献
20.
According to analysis on field data obtained by ADCP(Acoustic Doppler Current Profiler),the flow regime of the Yangtze River Estuary is studied by use of a 3-D numerical model.The flow field characteristics,under the influence of Coriolis force,saltwater intrusion and freshwater inflow and tidal current interaction,are depicted in details.The main driving forces and some important effective factors of lateral,longitudinal and horizontal circulation are also analyzed. 相似文献