【作者】 孔祥鹏；

【导师】 丁德文；

【作者基本信息】 大连海事大学 ， 环境科学， 2014， 博士

【摘要】 渤海严重污染面积总体的上升趋势和年度之间的增减表明：渤海的自净能力每年尚可消解部分严重污染区域、渤海现实污染负担逐步加重。辽东湾是渤海严重污染海区之一,主要污染物为无机氮、活性磷酸盐和石油类。本文研究辽东湾顶部严重污染区域的海域自净能力季节变化与排污调控策略,以促使经济与环境的和谐。辽东湾北部随季节变化显著的海洋环境因子为风、海冰、海域水温。本文以计算渤海二维流场为基础,在辽东湾顶部的严重污染海域布设示踪粒子,通过对比经历一个季度后有风条件(冬季另加海冰条件)和无风条件的高潮时刻示踪粒子的轨迹,研究季风(和海冰)对海域水交换(物理自净)能力的影响。同时调查水质随海水温度的变化,并确定以海洋异养菌总数随水温的变化来描述海域微生物自净能力的季节变化。示踪粒子轨迹分析表明,辽东湾顶部存在反时针的潮致余流,但季风导致的风海流是海域水交换的主要动力。夏季南风在辽东湾顶导致的反时针风海流与潮致余流同向,使湾顶严重污染区域内水体在两个月内可以进入辽东湾北部中央清洁水域实现净化。冬季北风导致的在辽东湾顶部的顺时针风海流在东岸形成较强的南向沿岸流,使聚集在仙人岛与长兴岛之间近岸海域的严重污染水体进入辽东湾口清洁水域而净化；海冰对海域水交换起迟滞作用。春季秋季的风海流和潮致余流方向相反且强度不足,不利于严重污染区域内的水交换。调查实验表明湾顶海洋异养菌数水温16℃时激增,水温20℃时的数值是水温-1.8℃时的32倍。综合考虑水动力和微生物条件,每年5月-9月辽东湾顶严重污染区域内被污染水体最容易被净化；一年中辽东湾顶严重污染面积从大到小依次为秋季>冬季>春季>夏季。离岸排放区域应选择在风海流的流路上(避开岸边混乱的余流)且距离海岸最近(经济性),夏季选在辽河口西侧离岸6km-15km的一个近似圆形区域；离岸排放区域四季不同,但是上述区域的南部可以基本满足其它季节的要求。更多还原

【Abstract】 1. The heavily polluted waters in Bohai Sea overall increase and it can rise and fall in different years. Two facts can be indicated, the first is that the Bohai sea has enough self-purification ability to make some heavily polluted waters clean. The second is that the pollution becomes more and more serious in Bohai Sea. Liaodong Bay is one of the most heavily polluted waters in Bohai Sea. Main pollutants are the inorganic nitrogen, active phosphate and oils. The seasonal variations of waters self-purification capacity and the regulation of the pollution discharge at the top of Liaodong Bay are studied in this dissertation. The research is helpful to economy development in harmony with the environment, as it is difficult to control the pollution sources and pollutants. The monsoon and water temperature as well as sea ice are the marine environmental conditions obviously changing with seasonal variations in the north of Liaodong Bay.2. Based on the Numerical simulations on two-dimensional current field of the Bohai Sea, the tracer particles are set up at the heavily polluted waters at the top of Liaodong Bay in the numerical model. The impact of the monsoon (and sea ice) on the sea water exchanges is researched by the method that the trajectories of the tracer particles at high tide are contrasted and analyzed during three-month calculation period under the action of the monsoon (and sea ice in winter) and without the action of the monsoon at the top of Liaodong Bay. The impact of water temperature on water quality indexes at the top of Liaodong Bay is researched by field surveys and laboratory tests. The change of the count of marine heterotrophic bacteria with the water temperature is regarded as the indicator that the microbiological condition is changing with seasons at the top of Liaodong Bay.3. Analysis of tracer particles trajectories show that there is a counterclockwise tide-induced lagrangian residual current at the top of Liaodong Bay, but the monsoon-induced current plays a more prominent role in water exchange in this sea area. The south wind-induced current is counterclockwise at the top of Liaodong Bay, being same as the direction of the tide-induced residual current in this sea area. The comprehensive result of the two currents can purify the heavily polluted water at the top of Liaodong Bay, by making the water enter the clean waters area at the center of the north of Liaodong Bay within two months. In winter, the wind-induced current resulted from strong north wind is clockwise at the top of Liaodong Bay, being opposite as the direction of the tide-induced lagrangian residual current in this sea area. The comprehensive result of the two currents can form the strong southward coast current along the east shore of Liaodong Bay. The coast current can purify the heavily polluted water along the east shore between the Xianren Island and the Changxing Island within three months, by making the water enter the clean waters area at the mouth of Liaodong Bay. The sea ice affects sluggishly the water exchange at the north of Liaodong Bay. The wind-induced current is clockwise at the top of Liaodong Bay, being opposite as the direction of the tide-induced lagrangian residual current in this sea area in spring and winter, and the wind-induced current is not very strong. The comprehensive result of the two currents is not conducive to water exchange at heavily polluted area at the top of Liaodong Bay. The surveys and laboratory tests show that the count of marine heterotrophic bacteria increases dramatically when the water temperature is over16℃. The count of marine heterotrophic bacteria in the water with a temperature of20℃is as32times as that in the water with a temperature of-1.8℃.4. Above all, the water in the heavily polluted area at the top of Liaodong Bay is most easily purified from May to September during a year from the comprehensive effect of the water exchange and the microbial degradation. The size of the heavily polluted area at the north of Liaodong Bay is the largest in autumn, the order of successively decreasing size being in winter, spring and summer. Offshore pollution discharge area should be in the wind-induced currents path in order to keep away from the disordered residual current field nearly to the shore. Meanwhile, offshore pollution discharge area should be close to the shore in order to save the investment. The area is not same in different seasons. In summer, it is a nearly circular area with a9km-diameter, the top of which is about6km away from the shore at the west of Liaohe river mouth. The southern part of the sea area is also suitable for spring and autumn.更多还原