北仑河口水交换能力及物质输运的数值模拟研究

Numerical Model Study of Water Exchange Ability and Substance Transport in Beilun Estuary

关键词:  北仑河口  COD浓度  水交换  ECOMSED模型

Key words:  Beilun Estuary  COD concentration  water exchange  ECOMSED model

摘要:

[目的]随着入海污染物的不断增加,北仑河口海域的生态环境保护面临严峻挑战,因此对其水交换能力和物质输运特征进行研究尤为重要。[方法]基于COD调查结果,应用ECOMSED模型模拟北仑河口海域的水交换能力以及夏季与冬季的COD输运特征。[结果]北仑河口海域的水交换半周期为4.5 d,水体交换80%的时间约为29 d。北仑河口海域夏季两侧的COD浓度比冬季高0.4 mg/L,冬季中央区域COD浓度则比夏季高,这一方面与夏季较强的羽状流引起的较强水交换有关,另一方面与该区域冬季存在气旋式涡旋有关。[结论]北仑河口海域的羽状流及环流结构对污染物浓度分布有重要影响。

Abstract:

[Objective] As the pollutants into the sea are increased gradually, Beilun Estuary is facing tough challenge.In order to protect the marine ecological environment in the estuary, it is necessary to research the characteristics of water exchange and pollutant transport.[Methods] Based on the observation results, the ECOMSED model is applied to simulate the water exchange ability and COD transport characteristics of summer and winter in Beilun Estuary.[Results] The half cycle of the water exchange between the estuary and outside ocean was about 4.5 d, whereas it needed about 29 d to refresh 80% water in the estuary.On the other hand, the COD concentration in the two sides of the estuary was 0.4 mg/L larger in summer than those in winter.But the COD concentration in the central area in winter was larger than that in summer, which was due to the strong water exchange ability induced by the strong river plume in summer and the cyclonic eddy existing there in winter.[Conclusions] The river plume and the circulation structure in the estuary have significant effect on the distribution of the pollutant concentration in Beilun Estuary.