基于高精度海洋动力模型的珠江口羽状流季节和年际变化规律研究
徐闯(1991—), 男, 河南省南阳市人, 硕士研究生, 主要从事近岸海洋动力模拟研究。E-mail:xuch46@mail2.sysu.edu.cn |
Copy editor: 林强
收稿日期: 2018-09-29
要求修回日期: 2018-12-04
网络出版日期: 2019-06-17
基金资助
中央高校基本科研业务费专项资金(17lgzd20)
热带海洋环境国家重点实验室(中国科学院南海海洋研究所)开放课题(LTO1605)
国家自然科学基金(41306105)
版权
Study on the seasonal and interannual variability of river plume in the Pearl River Estuary based on a high-resolution ocean dynamic model
Copy editor: LIN Qiang
Received date: 2018-09-29
Request revised date: 2018-12-04
Online published: 2019-06-17
Supported by
Fundamental Research Funds for the Central Universities(17lgzd20)
State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences(LTO1605)
National Natural Science Foundation of China(41306105)
Copyright
基于高精度海洋动力模型FVCOM (finite-volume community ocean model), 模拟分析了1999—2010年珠江口羽状流的季节和年际变化规律, 并结合经验正交函数(empirical orthogonal function, EOF)分析探讨了影响珠江口羽状流扩展变化的主要动力因子。采用模拟时段内的现场观测数据对多年模拟结果进行验证, 结果表明模型具有较高的精度, 能够较好地模拟珠江口羽状流的扩展变化规律。模拟结果显示, 珠江口羽状流存在显著的季节变化。夏季, 受大径流和西南风的影响, 羽状流的扩展呈现双向特征, 即粤西沿岸扩展和粤东离岸扩展同时存在, 扩展范围最大; 冬季, 径流衰减为最小值, 风场转变为强烈的东北风, 羽状流被紧紧挤压在西岸, 形成狭窄的条带状, 扩展范围最小; 春、秋两季属于过渡季节, 羽状流扩展情况类似, 均表现为沿岸向粤西扩展。年际变化层面, 夏季羽状流的年际变化最为显著, 呈现粤东扩展占优型、近似对称型和粤西扩展占优型三种形态; 春季羽状流的年际变化次之, 羽状流的差异主要体现在珠江口和粤西海域; 秋、冬两季羽状流的年际变化较小, 尤以冬季最小。EOF分析的第一模态可以解释整体变化的91.2%, 反映了径流量对珠江口羽状流的影响; 第二模态可以解释整体变化的4.1%, 反映了盛行风对珠江口羽状流的影响。
徐闯 , 许永基 , 胡嘉镗 , 李适宇 , 刘晋涛 . 基于高精度海洋动力模型的珠江口羽状流季节和年际变化规律研究[J]. 热带海洋学报, 2019 , 38(3) : 43 -52 . DOI: 10.11978/2018098
Based on the sea surface salinity data from 1999 to 2010 simulated by the high-resolution Finite-Volume Community Ocean Model (FVCOM), the seasonal and interannual variability of river plume in the Pearl River Estuary was analyzed and the main dynamic factors related to the variability were also discussed in combination with Empirical Orthogonal Function (EOF) analysis in this study. The field observation data during the simulation period were used to verify the simulation results for the 12 years, and the verification results showed that the model had higher accuracy and simulated the extension and variability of the plume fairly well. The simulated results showed that the plume exhibited significant seasonal variability. Affected by the high river discharge and southwesterly wind, the summertime plume exhibited a bidirectional structure with the plume extending westward attaching to the coast and eastward detaching from the coast. The extension area of the summertime plume was the largest. In winter, the river discharge attenuated to a minimum and the wind field changed into strong northeasterly wind. Consequently, the plume was squeezed to the western coast tightly to form a narrow band with the smallest extension area. The spring and autumn periods were transitional seasons, and the plume in these two seasons exhibited westward alongshore spreading. The summertime plume exhibited significant interannual variability with three main patterns, namely, the eastward extension dominated, approximately symmetric extension and westward extension dominated. In spring, the interannual variability of the plume was followed by that in summer and the variability mostly occurred in the western region and river estuary. The interannual variability in autumn and winter was not significant, especially in winter. The first EOF mode could explain 91.2% of the total variance, corresponding to the change in river discharge. The second EOF mode could explain 4.1% of the total variance, corresponding to the change in prevailing wind.
图2 盐度验证结果a—d为2006年7、8月珠江口表、底层盐度模拟值和观测值比对结果, e—p为1999—2010年香港环保署逐年观测盐度和模拟盐度比对结果 Fig. 2 Validation results of salinity. (a-d) The comparison results of simulated and observed salinity at both surface and bottom in Pearl River Estuary during July-August 2006. (e-p) The comparison results of observed and simulated salinity collected from Hong Kong Environmental Protection Department from 1999 to 2010 |
图3 1999—2010年多年平均的各个月份的径流量及口门分流比(a)、矢量风场(b)、标量风速(c)和30‰等盐度线围成的羽状流扩展面积(d)Fig. 3 Twelve-year-averaged river discharge and distribution ratios of the four western and eastern outlets (a), vector wind (b), scalar wind speed (c), and plume area enclosed by 30‰ isohaline in each month (d) |
图5 1999—2010年各个季节季均径流(a)、矢量风场(b)、标量风速(c)和30‰等盐度线围成的羽状流面积(d)Fig. 5 Twelve-year-averaged river discharge (a), vector wind (b), scalar wind speed (c), and plume area (d) in each season |
图8 1999-2010年月均珠江口表层盐度异常场EOF分解的第一空间模态(a)、第二空间模态(b)、第一时间模态(c)和第二时间模态(d)第一模态可以解释整体变化的91.2%, 第二模态可以解释整体变化的4.1% Fig. 8 First spatial mode (a), 2nd spatial mode (b), 1st temporal mode (c), and 2nd temporal mode (d) of EOF analysis of monthly mean sea surface salinity anomaly (‰) field during 1999-2010. The first mode can explain 91.2% of the total variance, and the second mode can explain 41.2% of the total variance |
The authors have declared that no competing interests exist.
作者已声明无竞争性利益关系。
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