【作者】 钱一婧；

【导师】 张鹰；

【作者基本信息】 南京师范大学 ， 海洋地理学， 2008， 硕士

【摘要】 人类对河口的开发与利用已有悠久的历史,现在的河口地区仍然是世界上人类经济活动最频繁、人口最稠密、环境变化影响最为深远的地带之一。然而,在经济高速发展的同时,河口地区的环境遭到人类高强度活动的干扰,影响了河口地区的可持续发展。对河口的水环境进行系统、科学的模拟、分析,对于今后进行水环境质量的规划、管理具有十分重要的意义。本论文以2007年7月对射阳河口进行实地观测所得数据为依据,主要研究射阳河口的水动力特征和水质情况。通过对射阳河口潮流和水质的计算分析,研究了其潮流场特征。在此基础上,对水质要素的扩散进行了研究。由于海洋污染主要来自于内陆河流的排放,因此本论文的研究工作对于河口陆源污染对江苏沿海河口及其邻近海域的影响,海域环境容量的确定,近海海域的环境保护策略的制订等都具有重要的理论价值和实践意义。论文主要内容和成果包括以下几个方面:(1)通过实测资料和翻阅国外相关参考文献,并经过多次的调试,确定了射阳河口EFDC模型的相关水动力水质参数,为后面的进一步模拟水质水动力条件奠定了基础。尝试引入了遥感影像反演海表温度的技术,初步反演出射阳河口海水表层温度。通过对遥感影像的大气、几何校正,利用影像的热红外波段进行计算,从而得到射阳河口海表温度,作为数值模拟的部分数据资料。(2)通过对潮位站和测点的流速、流向计算值和实测值的比较,得出模型不仅能够较好地体现潮位的变化过程,而且在射阳河口岸线、地形较为复杂的射阳河口也能较好地反映潮流的分布和变化。模型模拟的结果表明流场在垂向上存在一定差异,下层流速明显小于上层流速。这种现象是由于底部摩擦和垂直紊流混合作用形成的。这说明要模拟射阳河口流场应该充分考虑径流的作用,使用三维模拟。(3)利用建立的水质模型模拟射阳河口水质情况分布,误差分析表明水质模型具有较高精度。研究表明污染物主要来自径流的输入,易降解的有机氮颗粒和溶解性有机氮浓度基本上由河口向外围衰减的趋势,易降解有机碳颗粒、磷酸盐等物质受涨落潮的影响,逐渐向偏南方向扩散。(4)研究结果显示污染源对水体的影响范围主要是在污染源附近,随着时间的推移,污染源逐渐向外围扩散。射阳河口的水动力条件有利于污染物的稀释扩散。射阳河口是江苏省的典型河口,其排污总量在江苏省23条入海河流中仅次于长江口北支。因此研究其水动力过程和水质情况对于阐明人类活动对近海海域生态环境的影响有着非常重要的意义。更多还原

【Abstract】 It has been a long history since human began the development and utilization of the estuary regions, which is still of the most intensive economic activities, the densest population and the profoundest impact of environmental change on the world until now. However, with the rapid development of economy, environment of estuary regions are interrupted by intensive human activities, impeding the sustainable development of the estuary regions. A systematic and scientific simulation and analysis on estuarial water environment is of great importance for the planning and management of the quality of water environment in the future.In this thesis, it is mainly studied the hydrodynamic behavior and water quality condition of Sheyang Estuary area based on in situ observation there on July 2007. According to the calculation and analysis of tidal current and water quality on Sheyang Estuary region, the characteristic of tidal field and thereby the diffusion of water quality elements are studied. The research of this thesis has both theoretical and practical significance to water environment protection of Sheyang Estuary and the adjacent sea areas. Main contents and achievements of the thesis are as follows:1. Based on observation data and lots of references, after many times of experiments and adjustments, relative hydrodynamic and water quality parameters of EFDC model for the study area are determined, which sets up basis for the simulation of hydrodynamic and water quality condition in the next step. The retrieval of sea surface temperature by remote sending image is adopted to obtain the sea surface temperature of Sheyang Estuary. By atmospheric and geometric modification of the remote sensing image, and based on wave band calculation on thermal infrared wave band, sea surface temperature of Sheyang Estuary is obtained. This method reasonably depicts the variation of sea surface temperature, and provides sufficient data for the determination of temperature field in the model.2. On the comparison of flow rate and flow direction between calculation and observation at tide gauging station and observation plot, it is concluded that the model can both depict tidal fluctuation process and capture fairly well the distribution and variation of tidal current at Sheyang Estuary where the coastal line and topography are very complex. Results of simulation reveal that there are some differences in vertical flow field, that is, flow rate of lower layer is obviously smaller than that of the upper layer, which is a result of the compound function of friction at the bottom and vertical mixture of turbulence. Therefore a 3D simulation model should be applied to simulate flow field in Sheyang Estuary, to fully take into consideration the effect of runoff.3. Distribution of water quality in Sheyang Estuary area is simulated by the established water quality model, which reveals fairly high precision by residual analysis. It is indicated that pollutant mainly comes from runoff input, the density of degradable organic nitrogen particle and dissolvable organic nitrogen show a decline trend from the river mouth outwards.4. Research results reveal that the incidence to pollutant source to water body is mainly close to the pollutant source, while expand gradually with time. The hydrodynamic condition of the study advantages the dilution and diffusion of pollutant. As a typical estuary in Jiangsu Province, the total pollutant discharge at Sheyang Estuary ranks the second after north branch of Yangtze River among all the 23 rivers that flow to the sea in Jiangsu Province, therefore the research on hydrodynamic process and water quality condition of this region is of great importance to understand the human impact on eco-environment of coastal sea areas.更多还原