热带海洋学报 ›› 2010, Vol. 29 ›› Issue (1): 20-31.doi: 10.11978/j.issn.1009-5470.2010.01.020

• 海洋物理学 • 上一篇    下一篇

基于改进的RCA水质模型对珠江口夏季缺氧及初级生产力的数值模拟研究

张恒, 李适宇   

  1. 中山大学环境科学与工程学院, 广东 广州 510275
  • 收稿日期:2008-11-25 修回日期:2009-02-11 出版日期:2010-01-15 发布日期:2001-01-08
  • 作者简介:张恒(1981—), 男, 广东省广州市人, 博士, 主要从事水环境模拟与水污染管理研究。
  • 基金资助:

    广东省“908”专项专题二(珠江口主要环境问题分析与对策, GD908-02-03)

A numerical study on hypoxia and primary production in the Pearl River Estuary in summer using the modified RCA water quality model

ZHANG Heng, LI Shi-yu   

  1. School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
  • Received:2008-11-25 Revised:2009-02-11 Online:2010-01-15 Published:2001-01-08

摘要:

针对珠江口藻类生长受泥沙遮光限制明显的问题, 对RCA(row and column of Aesop)三维水质模型进行改进, 加入泥沙模块及悬沙遮光对藻类生长的限制作用。应用改进的RCA水质模型, 对珠江口的营养盐、浮游植物及溶解氧进行模拟研究, 结果显示, 改进的RCA水质模型较好地再现了洪季珠江口营养盐、浮游植物和溶解氧在水平及垂向上的空间分布, 这表明该水质模型能较好地反映珠江河口中生态因子的关键过程。珠江口的缺氧现象在物理和生化过程的共同作用下, 被限制在伶仃洋的西滩和中滩及磨刀门海域。在洪季, 大量冲淡水进入珠江口形成锋面, 颗粒态有机物(particulate organic matter, POM)在锋面的影响下, 大量集中沉降在伶仃洋的西滩及中滩特定区域及磨刀门外, 产生较高的底泥耗氧率(sediment oxygen demand, SOD)。而在高SOD的区域, 水体分层通常也较明显, 因而产生缺氧现象。另一方面, 伶仃洋水体中磷的限制作用明显, 加上悬浮泥沙的遮光作用, 不利于浮游植物生长, 使得初级生产力低; 而在陆架上, 悬沙浓度减少使初级生产力增加, 但由于海源颗粒有机碳(particulate organic carbon, POC)的沉积分散于整个陆架上, 无法产生伶仃洋内的高SOD区域, 加上水体分层不明显, 并没有产生缺氧现象。

关键词: 珠江口, 泥沙模块, 遮光效应, RCA三维水质模型

Abstract:

The RCA water quality model was incorporated with the sediment module and the light shading effect due to the high turbidity in the Pearl River Estuary (PRE). The modified RCA water quality model was then applied to the PRE. Results show that the modified RCA model can reproduce the distribution of nutrients, phytoplankton and dissolved oxygen (DO) in the PRE successfully, which means the modified model can capture the main processes of water quality in the PRE. In the wet season, huge amount of fresh water enters the PRE and results in a river plume. Particulate organic matter (POM) deposits intensely in specific areas of western and central shoal of the Lingdingyang Estuary and outside Modaomen as a result of the plumes. Furthermore, high deposition rate of POM in specific areas leads to high sediment oxygen demand (SOD), which coincides with the areas with strong stratification. High SOD and strong stratification lead to hypoxia. On the shelf areas, primary production increases as the suspended sediment concentration decreases, but the increasing primary production does not result in hypoxia as the marine particulate organic carbon (POC) spreads all over the shelf and the stratification is weak.

Key words: Pearl River Estuary (PRE), sediment module, shading effect, RCA water quality model