High-resolution Numerical Simulation Of Tidal Waves In The Global And East China Sea

Based on the Semi-implicit Cross-scale Hydroscience Integrated System Model(SCHISM)ocean model,this paper uses an unstructured triangular grid to construct a global ocean tide numerical model.The simulation results of the model are verified by using the measured tide station data,and the two are in good agreement.According to the simulation results,the same tide map of the four major oceanic components(M₂,S₂,K₁,O₁)was drawn,and the tidal wave distribution characteristics of the four major oceanic components were further analyzed.Finally,using the constructed global model to provide open boundary water level conditions for the regional model,regional tidal wave models(117.5?132°E,23.5?41°N)in the Bohai,Yellow and East China Seas were constructed,and4 Bohai,Yellow,and East China Seas were analyzed and studied.The tidal and tidal current characteristics of the main tidal components(M₂,S₂,K₁,O₁).The main research conclusions are as follows:(1)The distribution characteristics of global M₂tidal components are very little different from the comparison models(FES2014b,NAO.99b),and the distribution characteristics of tidal waves are very similar.There are 6 wet points in the Pacific Ocean,4tidal-free points in the Atlantic Ocean,and 3 tidal-free points in the Indian Ocean.There are two M₂subtidal high amplitude regions in the equatorial Pacific Ocean,the amplitude of which exceeds 40cm,even 60cm.Generally speaking,the amplitude of the M₂component in the waters near the east coast of the North Pacific and the North Atlantic is greater than that of the waters near the west coast.There are 9 tidal-free points distributed in the Pacific Ocean,4 tidal-free points in the Atlantic Ocean,and their positions are almost the same as the M₂tidal points,and 3 tidal-free points are distributed in the Indian Ocean.The amplitude of the S₂subtide is much smaller than that of the M₂subtide,and it does not exceed 20 cm in most sea areas.The distribution characteristics of global K₁tidal components are very little different from the comparison models(FES2014b,NAO.99b),and the distribution patterns of tidal waves are almost the same.There are 5 tidal-free points in the Pacific Ocean,3 tidal-free points in the Atlantic Ocean,and only 1 tidal-free point in the Indian Ocean.The amplitude of the K₁tidal component is generally small,and it tends to increase from the ocean to the coast.The spatial distribution of O₁component is similar to that of K₁component.There are 5 tidal-free points in the Pacific Ocean,2tidal-free points in the Atlantic Ocean,and 2 tidal-free points in the Indian Ocean.The amplitude of the O₁tidal component in the Pacific Ocean is relatively small,not exceeding20 cm in most sea areas,and there is an increasing trend from the ocean to the north and south poles.(2)There are 4 M₂tidal-free points distributed in the Bo,Huang,and East China Sea.The distribution characteristics of the M₂tidal component are similar to the results of previous studies,and the 60°isobaric line of the South Yellow Sea runs east-west.West Korea Bay,Jianghua Bay of the Yellow Sea,and the northern waters of the Taiwan Strait are the high-amplitude regions of tidal waves,with amplitudes exceeding 2m.The cotidal chart of S₂tidal component is similar to that of the M₂tidal component,but the amplitude is relatively small.There are two K₁tidal-free points distributed in the Bo,Huang,and East China Seas,all of which are counterclockwise rotating tidal wave systems.The high-amplitude zone of the K₁tidal component is located at the top of the Liaodong Bay and West Korea Bay,and the maximum amplitude exceeds 40 cm.The distribution characteristics of the O₁component are similar to the K₁component,but the amplitude is relatively small.(3)The M₂tidal current ellipse in the East China Sea and the Bohai Sea mainly rotates clockwise,and the tidal current ellipse in the Yellow Sea mainly rotates counterclockwise.The M₂tidal tidal current strong current area is mainly located in the coastal waters.In the East China Sea,the Hangzhou Bay,the Yellow Sea's Jianghua Bay and the West Korea Bay,the tidal velocity reaches or exceeds 1.0m/s;the weak current areas are mainly located at the edge of the continental shelf of the East China Sea,the Taiwan Strait,the Tsushima Strait,the central part of the South Yellow Sea and the Bohai Sea.The elliptical distribution pattern of S₂tidal current is basically the same as that of M₂tidal current ellipse,but the value is relatively small.The K₁tidal tidal current ellipse in the East China Sea mainly rotates clockwise,while the Bohai Sea and the Yellow Sea are the opposite,and the tidal current ellipse mainly rotates counterclockwise.The K₁tidal current strong current area is located in the Korean Strait and the Bohai Strait.The maximum velocity of the Korean Strait reaches 30cm/s,while the maximum velocity of the Bohai Strait is close to 50cm/s.The K₁tidal current velocity in the central waters of the Yellow Sea and the East China Sea is relatively small,and basically does not exceed 10 cm/s.The tidal current distribution characteristics of O₁tidal component are basically similar to those of K₁tidal component.The strong tidal current area is also located in the Bohai Strait and the Korean Strait,with a maximum velocity of 30 cm/s.