摘要:
根据大通水文站的流量和引水船站的盐度系列资料,应用谱分析方法研究长江口径流、盐度的变化规律及两者的相互关系.分析表明,长江口径流存在4～8a,2～3a,1.5a,1a,30～60d及20d的及化周期;盐度存在5～10a,2～3a,1.5a,1a,0.5a,40～50d,26～30d,14～15d7～8d及3.5d的变化周期.径流和盐度的谱结构在各水文年基本一致,均以1a周期变化占优势,但盐度谱结构在高频部分较径流的谱结构具有更大的振荡.盐度与流量的5～10a,2～3a,1.5a,1a的周期振动上存在高相关.径流对盐度变化的影响主要体现在低频部分.在低频变化中表现为盐度变化滞后于径流变化,在高频带呈同步变化.
关键词:
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径流 /
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盐度 /
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谱分析 /
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长江河口
Abstract:
The spectrum analysis is applied to analyse the fluctuations of the discharge and salinity, the characteristics of correlation between salinity and discharge in the Changjiang Estuary.The results show that the quasi-periods of discharge include 4.0-8.0,2.0-3.0,1.5 a, 30-60 and 20 d; the quasi-periods of salinity are 5.0-10.0, 2.0-3.0,1.5,1.0, 0.5 a, 40.0-50.0,7.0-8.0 and 3.5 d.The spectrum structures of salinity in different typical hydrologic years are almost similar to those of discharge.The dominant quasi-periods of discharge and salinity are 1 a.The high-frequency vibration of salinity is stronger than that of discharge.The analysis also shows that the close correlation is existed between salinity and discharge, their correlation periods are 5.0-10.0, 2.0-3.0, 1.5,1.0 and 0.5 a.The low-frequency fluctuation of salinity is primarily affected by discharge and lags the fluctuation of discharge.
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