It is very important to study the nontidal region, because characteristics in this area are very useful to us, for example, the tide range is small and the tide current is very strong. Suspended load isn’t easy to de...It is very important to study the nontidal region, because characteristics in this area are very useful to us, for example, the tide range is small and the tide current is very strong. Suspended load isn’t easy to deposite and the bed load is easy to move along the sea bed. Since 1936 many scientists think that there is a nontidal point M2 in the old eatuary (38°-38°10′N, 119°-119°20′E), and have determined the location of nontidal point. According to our observation, it isn’t a nontidal point but a nontidal line. This line is located near the section B.On the 15th day of lunar calendar this line is just located at section B, and in other days this line moves toward section A, but does’nt arrive in seetion A. The tide data that,have been observed on coast tide stations give eloquent proof of fact of nontidal line. In this region of near nontidal line the current speed is more than 90cm/sec., and the maximum is 120cm/sec. The minimum of tide range is about 30cm and the maximum is about 100cm. During the flood tide the current direction is south-east, and north-weat during the ebb tide. The residual current speed on section B is about 0.2 knot,and flow into north-west.展开更多
The Huanghe River is the second largest river in our country. The average annual runoff at the estuary is 44.28 billion cubic meters, the average annual suspended load is 1.12 billion tons, of which 24% was deposited ...The Huanghe River is the second largest river in our country. The average annual runoff at the estuary is 44.28 billion cubic meters, the average annual suspended load is 1.12 billion tons, of which 24% was deposited on the delta, 40% on the coast and the rest 36% is considered to be carried into the deep sea by various dynamic factors. We've measured the temperature, salinity, current and suspended load in the estuary from autumn of 1983 to summer of 1984 for building a harbour in future. According to our data and other historical data from some institutes, we've obtained following conclusions: 1) The distribution of temperature in winter is different with from that in summer: the contours of temperature in winter is parallel to coast line,and the contours of temperature in summer is coincident with latitudes. 2) The salinity in summer is lower than that in winter. There are three tongues of low values of salinity at the estuary in summer. They are pointed to North,North-east and South-east respectively. Only two tongues are appeared in winter-northward and south-eastward. 3) The distribution of suspended load is similar to the distribution of salinity,There are three tongues of high values of suspended load at the estuary in summer, they are pointed to North,North-east and Southeast respectively,the quantity of suspended load per litre in winter is much than in summer. 4) The influence of Huanghe River to North area of the estuary is less than to Laichou Bay. 5) The velocities of tide current at the estuary are very large.The maximum value is about 150era/see, and the directions of tide current are parallel to coastline.展开更多
To select from among forecasting approaches to shallow water wave five that are more important and currently employed are used to hindcast a wind-wave in the western Laizhou Bay in this paper. The prediction values ob...To select from among forecasting approaches to shallow water wave five that are more important and currently employed are used to hindcast a wind-wave in the western Laizhou Bay in this paper. The prediction values obtained are compared with wave data in the vicinity of the investigated water area, from which more reasionable values selected are treated as significant wave height (H1/3) and average wave period(-↑T) of a 50-year return period at a depth of 20m below the mean low water, both values being 5.50 metres and 9.50 seconds respectively.展开更多
It’s very important to study the transportation of suspended matter for the coats engineering. We have to understand the quantity and direction of the movement of suspended matter for studying the change of coast and...It’s very important to study the transportation of suspended matter for the coats engineering. We have to understand the quantity and direction of the movement of suspended matter for studying the change of coast and deposit of sediment on the sea bed. For this porpose we have measured the currents and the quantity of suspended matter near the section B in different seasons since 1983.According to data and calculation, we’ve got the following conclusions: 1) The quantity of suspended matter transported by tidal current through the section B is about 19.6 million tons each year, but the transportation, quantity is the same in both direction of flood tide and ebb tide. 2) The quantity of suspended matter removed by residual current is about 8.57 million tons each year, the direction of tran.spotation points to north'west. 3) The transportation quantity of suspended matter due to the winddriven current in. storm weather is about 0.95 million, tons each year,the direction of transportation points to south.展开更多
Tidal current asymmetry due to existence of shallow water constituent current is studied. It is found that there is a relationship between the asymmetry and the reversion of tidal current rotating.The influence functi...Tidal current asymmetry due to existence of shallow water constituent current is studied. It is found that there is a relationship between the asymmetry and the reversion of tidal current rotating.The influence function for determining when the reversion occurs can be used for finding characteristics of tidal current asymmetry.For a shallow water area where semidiurnal current dominates, the current characteristic at extremum moment ~↑t of the influence function is discovered:if both M2 and M4 constituent currents are in the same direction at the moment ~↑t, then at t=~↑t+TM2/2 their directions are opposite. It is convenient to discuss the asymmetry by the use of a parameter α which is defined as a ratio:-WM4 (~↑t)/WM2 (~↑t).In most cases,if α is larger than zero，the reversion of tidal current rotating will be occurring about the moment ~↑t, and current magnitude be adifference of Mz and M4 current magnitudes at ~↑t. If α is smaller than zero,the reversion will not happen,and current magnitude is a sum of both constituent current magnitudes at ~↑t. For the case that|α| is larger than 1,the current directions at ~↑t and ~↑t +TM2/2 are the same, as to |α| which is smaller than 1,two directions at two moments are opposite. Especially when ~↑t happens to be close to moments of both M2 and M4 current maximums, influence of the asymmetry will be significant, the larger theM4 current maximum, the more asymmetric the current.The influence of the asymmetry on sand movement is also dealt with,such an asymmetry will lead to the transportation of sand towards certain direction.展开更多
In order to test dynamic response of storm serges to the track, the intensity and the speed of typhoon on the coastal areas of Zhejiang and Jiangsu Provinces, the authors have made an attempt to simulate the model tyh...In order to test dynamic response of storm serges to the track, the intensity and the speed of typhoon on the coastal areas of Zhejiang and Jiangsu Provinces, the authors have made an attempt to simulate the model tyhoon surges on that regions. This work has been carried out by the finite-difference scheme with the quadratic conservation. The model tyhoons have been assumed to hit the coast of Zhejiang and Jiangsu provinces along the five main tracks and to be different in the intensity and the travelling speed respectively, By this computation some conclusions which are useful to further simulate typhoon surges on those regions have been obtained.展开更多
文摘It is very important to study the nontidal region, because characteristics in this area are very useful to us, for example, the tide range is small and the tide current is very strong. Suspended load isn’t easy to deposite and the bed load is easy to move along the sea bed. Since 1936 many scientists think that there is a nontidal point M2 in the old eatuary (38°-38°10′N, 119°-119°20′E), and have determined the location of nontidal point. According to our observation, it isn’t a nontidal point but a nontidal line. This line is located near the section B.On the 15th day of lunar calendar this line is just located at section B, and in other days this line moves toward section A, but does’nt arrive in seetion A. The tide data that,have been observed on coast tide stations give eloquent proof of fact of nontidal line. In this region of near nontidal line the current speed is more than 90cm/sec., and the maximum is 120cm/sec. The minimum of tide range is about 30cm and the maximum is about 100cm. During the flood tide the current direction is south-east, and north-weat during the ebb tide. The residual current speed on section B is about 0.2 knot,and flow into north-west.
文摘The Huanghe River is the second largest river in our country. The average annual runoff at the estuary is 44.28 billion cubic meters, the average annual suspended load is 1.12 billion tons, of which 24% was deposited on the delta, 40% on the coast and the rest 36% is considered to be carried into the deep sea by various dynamic factors. We've measured the temperature, salinity, current and suspended load in the estuary from autumn of 1983 to summer of 1984 for building a harbour in future. According to our data and other historical data from some institutes, we've obtained following conclusions: 1) The distribution of temperature in winter is different with from that in summer: the contours of temperature in winter is parallel to coast line,and the contours of temperature in summer is coincident with latitudes. 2) The salinity in summer is lower than that in winter. There are three tongues of low values of salinity at the estuary in summer. They are pointed to North,North-east and South-east respectively. Only two tongues are appeared in winter-northward and south-eastward. 3) The distribution of suspended load is similar to the distribution of salinity,There are three tongues of high values of suspended load at the estuary in summer, they are pointed to North,North-east and Southeast respectively,the quantity of suspended load per litre in winter is much than in summer. 4) The influence of Huanghe River to North area of the estuary is less than to Laichou Bay. 5) The velocities of tide current at the estuary are very large.The maximum value is about 150era/see, and the directions of tide current are parallel to coastline.
文摘To select from among forecasting approaches to shallow water wave five that are more important and currently employed are used to hindcast a wind-wave in the western Laizhou Bay in this paper. The prediction values obtained are compared with wave data in the vicinity of the investigated water area, from which more reasionable values selected are treated as significant wave height (H1/3) and average wave period(-↑T) of a 50-year return period at a depth of 20m below the mean low water, both values being 5.50 metres and 9.50 seconds respectively.
文摘It’s very important to study the transportation of suspended matter for the coats engineering. We have to understand the quantity and direction of the movement of suspended matter for studying the change of coast and deposit of sediment on the sea bed. For this porpose we have measured the currents and the quantity of suspended matter near the section B in different seasons since 1983.According to data and calculation, we’ve got the following conclusions: 1) The quantity of suspended matter transported by tidal current through the section B is about 19.6 million tons each year, but the transportation, quantity is the same in both direction of flood tide and ebb tide. 2) The quantity of suspended matter removed by residual current is about 8.57 million tons each year, the direction of tran.spotation points to north'west. 3) The transportation quantity of suspended matter due to the winddriven current in. storm weather is about 0.95 million, tons each year,the direction of transportation points to south.
文摘Tidal current asymmetry due to existence of shallow water constituent current is studied. It is found that there is a relationship between the asymmetry and the reversion of tidal current rotating.The influence function for determining when the reversion occurs can be used for finding characteristics of tidal current asymmetry.For a shallow water area where semidiurnal current dominates, the current characteristic at extremum moment ~↑t of the influence function is discovered:if both M2 and M4 constituent currents are in the same direction at the moment ~↑t, then at t=~↑t+TM2/2 their directions are opposite. It is convenient to discuss the asymmetry by the use of a parameter α which is defined as a ratio:-WM4 (~↑t)/WM2 (~↑t).In most cases,if α is larger than zero，the reversion of tidal current rotating will be occurring about the moment ~↑t, and current magnitude be adifference of Mz and M4 current magnitudes at ~↑t. If α is smaller than zero,the reversion will not happen,and current magnitude is a sum of both constituent current magnitudes at ~↑t. For the case that|α| is larger than 1,the current directions at ~↑t and ~↑t +TM2/2 are the same, as to |α| which is smaller than 1,two directions at two moments are opposite. Especially when ~↑t happens to be close to moments of both M2 and M4 current maximums, influence of the asymmetry will be significant, the larger theM4 current maximum, the more asymmetric the current.The influence of the asymmetry on sand movement is also dealt with,such an asymmetry will lead to the transportation of sand towards certain direction.
文摘In order to test dynamic response of storm serges to the track, the intensity and the speed of typhoon on the coastal areas of Zhejiang and Jiangsu Provinces, the authors have made an attempt to simulate the model tyhoon surges on that regions. This work has been carried out by the finite-difference scheme with the quadratic conservation. The model tyhoons have been assumed to hit the coast of Zhejiang and Jiangsu provinces along the five main tracks and to be different in the intensity and the travelling speed respectively, By this computation some conclusions which are useful to further simulate typhoon surges on those regions have been obtained.
