Tidal analysis in the venturi-shaped area between Zhenhai and Shenjiamen in the East China Sea

作     者：吕华庆 胡建炯 

作者机构：Marine Science School of Zhejiang Ocean University Zhejiang Institute of Hydraulics & Estuary 

出 版 物：《Chinese Journal of Oceanology and Limnology》 (中国海洋湖沼学报（英文版）)

年 卷 期：2009年第27卷第1期

页      面：103-111页

核心收录：

学科分类：07[理学] 0707[理学-海洋科学] 

基　　金：Supported by Study on the Temporal and Spatial Distributions of Temperature and Salinity in Xiangshan Bay and the Northern Zhejiang Coastal Waters in the East China Sea of the Education Department of Zhejiang Provincial Government of China (Project No. 20061134) Study on Environment Dynamics and Nutrient Circulation in Xiangshan Bay and its Surrounding Areas in the East China Sea of the Second Institute of Oceanography, State Oceanic Administration, China (Project No. SOED0605) 

主　　题：East China Sea harmonic analysis Luotou Waterway tidal features venturi-shaped area Zhejiang coastal water 

摘      要：In order to better understand the general tidal features in the venturi-shaped area between Zhenhai and Shenjiamen in the northern coastal region of Zhejiang Province in the East China Sea, the tidal data were obtained from both the three permanent tide stations of Zhenhai, Dinghai and Shenjiamen, and four temporary tide stations of Mamu, Chuanshan, Guoju and Liuheng, along with the current speed being observed at Luotou Waterway. Results from harmonic analysis show that: (1) The area was dominated by shallow water tides with irregular semi-diurnal features, and the smallest tidal range occurred in the area near a crossing line between Zhenhai and Dinghai stations, indicating that a tidal node existed in the southern Hangzhou Bay; (2) Formulae, HS2/HM2 0.4 and gM2-(gK1+gO1)=270° (where H and g are harmonic constants), could be used as judging criteria for high and low tidal level diurnal inequalities; (3) The duration difference between ebb and flood tides could be roughly assessed by the ratio of HM4 vs. HM2; and the larger the ratio is, the bigger the duration difference is. At the same time, the duration period could be assessed by 2gM2-gM4, the epoch difference between M2 and M4 tidal constituents. If 2gM2-gM4 180°, then the ebb duration is longer than the flood duration; if 180° 2gM2-gM4 360°, the result is reversed; (4) Taking Dinghai station as a center point, the highest tidal levels and the average high tidal levels, as well as the average tidal ranges at all stations became higher and larger both southeastwards and northwestwards, while the lowest tidal levels and the average low tidal levels appeared to be lower both southeastwards and northwestwards; and (5) The tidal patterns were not all in line with the tidal current patterns. As a conclusion, the smallest tidal range occurred in the narrow part of the venturi-shaped area. Along the both sides of the area, the highest tidal level and tidal range became higher and larger, while the lowest tidal lev