Tidal analysis in the venturi-shaped area between Zhenhai and Shenjiamen in the East China Sea
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, a...
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| Published in: | Chinese journal of oceanology and limnology Vol. 27; no. 1; pp. 103 - 111 |
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| Main Author: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
Heidelberg
SP Science Press
01-02-2009
Springer Nature B.V Marine Science School of Zhejiang Ocean University, Zhoushan 316004, China%Zhejiang Institute of Hydraulics & Estuary, Hangzhou 310020, China |
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| Online Access: | Get full text |
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| Summary: | 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 level became lower with the increase of the distance from the narrow throat area. This is somehow different from the theory that the tidal level increases gradually when it moves towards the top narrow area of a V-shaped bay or estuary. |
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| Bibliography: | P227 TU251.3 East China Sea Luotou Waterway 37-1150/P East China Sea; harmonic analysis; Luotou Waterway; tidal features; venturi-shaped area;Zhejiang coastal water venturi-shaped area tidal features harmonic analysis Zhejiang coastal water ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 0254-4059 2096-5508 1993-5005 2523-3521 |
| DOI: | 10.1007/s00343-009-0103-2 |