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171.
本文根据1988年10月20~24日“向阳红09号”调查船在奄美大岛以西海区进行调查时,在陆架斜坡上的表均温层的底部,即50m附近的深层上,出现一个黑潮锋面涡。不论在平面上形成的特点,还是在断面上水系配置的形式,它与春季黑潮锋面涡的特征极为相似。说明秋季东海同样存在陆架水与黑潮水在水平方向交换与混合。 相似文献
172.
Zhang Furan Zhao Jun Zhang Xueqin Assistant Researcher Tianjin Research Institute of Water Transport Engineering Tianjin Assistant Engineer Tianjin Research Institute of Water Transport Engineering Tianjin 《中国海洋工程》1993,(2)
In respect of an offshore berthing pillar, the test study result of current force acting on mooring ships is described in this paper. Empirical and semi-empirical relationships of current force coefficient are given according to the angle between the flow direction and the ship's longitudinal axis, which are coincident with the result of theoretical analysis. 相似文献
173.
Qiu Dahong 《中国海洋工程》1992,(2)
Based on the 1st order cnoidal wave theory, the nonlinear wave diffraction around a circular cylinder in shallow water is studied in this paper. The equation of the wave surface around the cylinder is formulated and by using this formula the wave surface elevation on the cylinder surface can be obtained. In this paper, the formula for calculating the cnoidal wave force on a circular cylinder is also derived. For the wave conditions which are often encountered in practical engineering designs, the ratios of the nonlinear wave forces to the linear wave forces are calculated, and the results are plotted in this paper for design purposes. In order to verify the theoretical results, model tests are conducted. After comparing the test results with the theoretical ones, it is concluded that, in shallow water, for the case of T g / d~(1/2) > 8-10 and H / d > 0.3, the cnoidal wave theory should be used to calculate the wave action on a cylindrical pier. 相似文献
174.
175.
Modelling nitrogen and phosphorus cycles and dissolved oxygen in the Zhujiang Estuary Ⅰ. Model development 总被引:1,自引:0,他引:1
wrmcrloxHuman activities related to the population growth and developrnent of industry and rnwhci-pality have led to the incrouing hadings of various POllutants into estudries during the past fewdecades. These increasing edlutant lOadings have caused declined estuallne hedth which can bemereured by a vdriety of indices. In order to obtain solutions to environrnent problerns, re-sources manageTnnt apencies are supporting a holistic approach to envirorirnental management.An effcient strategy t… 相似文献
176.
Vertical variations of wave-induced radiation stress tensor 总被引:3,自引:0,他引:3
INTRODUcrIONThe concept of radiation stress was deve1oPed by tonguet--Higgins and Stewart (1964 ),who intreduced the definition of radiation stress as the excess mornentum due to the presence ofwaves, on the basis of time-averaged laws of Newtonian fluid mechanics and the assmption ofa unifOrm velocity distribution over depth. Subequently, the theory has been applied success-fully in the investigation of phenomena such as wave set-up and set--down (Bowen et al.,l968), longshore currents … 相似文献
177.
The European Regional Seas Ecosystem Model (ERSEM) has been coupled with a two-dimensional depth-averaged transport model of the Humber plume region and run to simulate 1988–1989. Simulations of the spatial and temporal variations in chlorophyll-a, nitrate, phosphate and suspended particulate matter distributions in winter, spring and summer show how the development of the spring bloom and subsequent maintenance of primary production is controlled by the physicochemical environment of the plume zone. Results are also shown for two stations, one characterised by the high nutrient and suspended matter concentrations of the plume and the other by the relatively low nutrient and sediment concentrations of the offshore waters. The modelled net primary production at the plume site was 105 g C m−2 a−1 and 127 g C m−2 a−1 offshore. Primary production was controlled by light limitation between October and March and by the availability of nutrients during the rest of the year. The phytoplankton nutrient demand is met by in-situ recycling processes during the summer. The likely effect of increasing and decreasing anthropogenic riverine inputs of nitrate and phosphate upon ecosystem function was also investigated. Modelling experiments indicate that increasing the nitrogen to silicate ratio in freshwater inputs increased the production of non-siliceous phytoplankton in the plume. The results of this model have been used to calculate the annual and quarterly mass balances describing the usage of inorganic nitrogen, phosphate and silicate within the plume zone for the period of the NERC North Sea survey (September 1988 to October 1989). The modelled Humber plume retains 3.9% of the freshwater dissolved inorganic nitrogen, 2.2% of the freshwater phosphate and 1.3% of the freshwater silicate input over the simulated seasonal cycle. The remainder is transported into the southern North Sea in either dissolved or particulate form. The reliability of these results is discussed. 相似文献
178.
179.
H. Hummel C. Amiard-Triquet G. Bachelet M. Desprez J. Marchand B. Sylvand J.C. Amiard H. Rybarczyk R.H. Bogaards J. Sinke Y. De Wit L. De Wolf 《Journal of Sea Research》1996,35(4):315-321
Variation in the sensitivity to stress of Macoma balthica was measured in several French and Dutch estuaries. For adult and juvenile Macoma balthica exposed to copper under conditions of starvation, differences in mortality rate, condition, glycogen, burrowing rate and copper content were assessed. No significant differences were observed between adults and juveniles; the influence of treatment and origin was always evident. Animals from the most southern estuaries, Loire and Gironde, near to the species's southern limit of distribution, showed, in the field, the strongest deviations for the ecophysiological traits measured, and were in the experiments the most sensitive to stress. 相似文献
180.
用三峡及邻区(东经108°~113°,北纬29°~33°)地质资料,地震资料,现 场地应力测量资料论证三峡及邻区晚第三纪以来构造应力场稳定性及其分区特 征。 相似文献