基于粒子示踪法的香溪河环流模式及营养盐补给分析  

Analysis of Water Circulation and Nutrient Supply of Xiangxi Bay Based on Particle Tracing Method

作　　者：黄宇擘 徐慧[1,2] 龙良红[1,2] 纪道斌[1,2] HUANG Yubo;XU Hui;LONG Lianghong;JI Daobin(Hubei Field Observation&Scientific Research Stations for Water Ecosystem in Three Gorges Reservoir,China Three Gorges Univ.,Yichang 443002,China;Engineering Research Center of Eco-environment in Three Gorges Reservoir Region,Ministry of Education,China Three Gorges Univ.,Yichang 443002,China)

机构地区：[1]三峡大学三峡水库生态系统湖北省野外科学观测研究站,湖北宜昌443002 [2]三峡大学三峡库区生态环境教育部工程研究中心,湖北宜昌443002

出　　处：《三峡大学学报（自然科学版）》2023年第5期77-86,共10页Journal of China Three Gorges University：Natural Sciences

基　　金：国家自然科学基金项目(52079069,52009066,51909135);湖北省自然科学基金项目(2022CFB807)。

摘　　要：针对香溪河库湾分层异重流对河段营养盐输移的影响,利用CE-QUAL-W2模型建立香溪河库湾立面二维水质模型,模拟2015全年库湾水动力过程,采用粒子示踪技术对不同环流模式下的营养盐输移过程、补给途径进行分析.结果表明:香溪河库湾水体环流过程受上游入流和下游倒灌两种驱动力的影响,根据异重流潜入深度可基本存在6种环流模式,而对水环境影响较大、持续时间较长的典型环流模式有3种,分别是下游表层倒灌-上游底层入流模式、下游中层倒灌-上游底层入流模式和下游底层倒灌-上游底层入流模式.第一种环流持续时间最长(160 d),利于增大混合层深度(库湾整体大环流),缩短水体滞留时间(粒子留存量最小).香溪河上游顺坡异重流对以P3点为代表的上游回水末端的营养盐补给贡献率达到85%,水平补给和掺混补给是真光层营养盐补给的主要方式;中下游水体营养盐外源输入主要是长江干流水体倒灌补给作用.随着干流水体的倒灌深度增加,水头碰撞导致库湾垂向掺混增强,上游顺坡异重流对库湾真光层营养盐的贡献率上升,而下游倒灌水体的贡献率持续降低.In order to ascertain the effects of stratified density currents on nutrient transport in Xiangxi Bay,a tributary bay in the Three Gorges Reservoir,a two-dimensional hydrodynamic and water quality model called CE-QUAL-W2 model was established to simulate the water circulation characteristics of Xiangxi Bay in 2015,and the nutrient transport process and recharge pathways by using particle tracing method was analyzed.The results show that the water circulation patterns of Xiangxi Bay are affected by the upstream inflow and downstream stratified intrusion currents,and six circulation patterns are summarized according to the plunge points of density currents.Among them,there are three frequent typical circulation modes that have a large impact and a long duration on the water environment,namely the underflow from the upstream combined with the intrusive overflow,interflow and underfow from the downstream.The pattern of upstrem underflow-downstream overflow has the longest duration(160 d),which is conducive to increasing the mixed layer depth(the overall large circulation of Xiangxi Bay)and shortening the retention time of the water body(the smallest particle conservation).The nutrients at the end of backwater in Xiangxi Bay mainly come from the upstream inflow,and the nutrient contribution rate reached more than 85%,in the manners of horizontal and mixing supply.The nutrients in the middle and lower reaches of Xiangxi Bay mainly come from the intrusion currents of the mainstream in the Three Gorges Reseervoir.With the movement of the intrusion current from the surface to the bottom layer,the nutrients supply of the upstream flow on the surface layer of Xiangxi Bay gradually increase,while the supply of the downstream intrusion currents on the surface layer gradually weaken.As the downstream intrusion current moved from the surface to the bottom,the nutrient supply from upstream inflow to the surface water of the Xiangxi Bay gradually increase,while the supply from downstream intrusion currents to the surface water we

关 键 词：环流模式 营养盐 粒子示踪法 水动力模型 三峡水库 

分 类 号：X524[环境科学与工程—环境工程]