scholarly journals Storm Surges in the Bohai Sea: The Role of Waves and Tides

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1509
Author(s):  
Yuanyi Li ◽  
Huan Feng ◽  
Guillaume Vigouroux ◽  
Dekui Yuan ◽  
Guangyu Zhang ◽  
...  

A storm surge is a complex phenomenon in which waves, tide and current interact. Even though wind is the predominant force driving the surge, waves and tidal phase are also important factors that influence the mass and momentum transport during the surge. Devastating storm surges often occur in the Bohai Sea, a semi-enclosed shallow sea in North China, due to extreme storms. However, the effects of waves on storm surges in the Bohai Sea have not been quantified and the mechanisms responsible for the higher surges that affect part of the Bohai Sea have not been thoroughly studied. In this study, we set up a storm surge model, considering coupled effects of tides and waves on the surges. Validation against measured data shows that the coupled model is capable of simulating storm surges in the Bohai Sea. The simulation results indicate that the longshore currents, which are induced by the large gradient of radiation stress due to wave deformation, are one of the main contributors to the higher surges occurring in some coastal regions. The gently varying bathymetry is another factor contributing to these surges. With such bathymetry, the wave force direction is nearly uniform, and pushes a large amount of water in that direction. Under these conditions, the water accumulates in some parts of the coast, leading to higher surges in nearby coastal regions such as the south coast of the Bohai Bay and the west and south coasts of the Laizhou Bay. Results analysis also shows that the tidal phase at which the surge occurs influences the wave–current interactions, and these interactions are more evident in shallow waters. Neglecting these interactions can lead to inaccurate predictions of the storm surges due to overestimation or underestimation of wave-induced set-up.

2013 ◽  
Vol 54 (62) ◽  
pp. 97-104 ◽  
Author(s):  
Chengyu Liu ◽  
Wei Gu ◽  
Jinlong Chao ◽  
Lantao Li ◽  
Shuai Yuan ◽  
...  

AbstractTo investigate the spatio-temporal characteristics of sea-ice resource, we used sea-ice volume to measure the amount of sea-ice resource in the Bohai Sea, China. The sea-ice area was extracted from Advanced Very High Resolution Radiometer (AVHRR) remote-sensing images using the zonal threshold method. The sea-ice thickness was estimated using a sea-ice model based on shortwave radiation theory and field measurements. The spatio-temporal characteristics of sea-ice volume were then analysed using GIS technology. The results indicate that the Bohai Sea experienced two sea-ice volume peaks in winter 2009/10. The largest sea-ice volume was in Liaodong Bay (∼80.26% of the entire sea-ice volume of the Bohai Sea). Bohai Bay had the second largest ice volume, and Laizhou Bay the smallest. The relationship between sea-ice volume and distance from shore is essentially exponential. The proportion of total sea-ice volume that is 0–10 km from shore is ∼42.43%, whereas the proportion that is 100–110 km from shore is only 0.002%.


2020 ◽  
Author(s):  
Hailong Li ◽  
Xiaolang Zhang ◽  
Xuejing Wang ◽  
Kai Xiao ◽  
Yan Zhang ◽  
...  

<p>With an area of about 77,000 km<sup>2</sup>, the Bohai Sea includes three bays: Laizhou Bay, Bohai Bay and Liaodong Bay. In this study, <sup>228</sup>Ra, δD, δ<sup>18</sup>O and salinity data were collected from surface seawater in the entire Bohai Sea, river water, and groundwater along its coastline in August 2017. Based on the spatial distributions of δD, δ<sup>18</sup>O, and salinity in surface water in the entire Bohai Sea and δD-salinity relations, the marine hydrological processes were investigated and the members of river water and groundwater for δD and δ<sup>18</sup>O were determined. The steady-state mass-balance models of δD, δ<sup>18</sup>O and salinity are given and used to estimate submarine fresh groundwater discharges and the flushing times of the entire Bohai Sea and its three bays. Based on the results of the flushing times, the steady-state mass-balance model of <sup>228</sup>Ra is used to estimate submarine groundwater discharges of the entire Bohai Sea and its three bays.</p>


Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5471
Author(s):  
Lina Cai ◽  
Juan Bu ◽  
Danling Tang ◽  
Minrui Zhou ◽  
Ru Yao ◽  
...  

We analyzed the distribution of chlorophyll-a (Chla) in the Bohai Sea area based on data from the geosynchronous orbit optical satellite Gaofen-4 (GF-4), which was launched in 2015, carrying a panchromatic multispectral sensor (PMS). This is the first time the geosynchronous orbit optical satellite GF-4 remote-sensing data has been used in China to detect the Chla change details in the Bohai Sea. A new GF-4 retrieved model was established based on the relationship between in situ Chla value and the reflectance combination of 2 and 4 bands, with the R2 of 0.9685 and the total average relative error of 37.42%. Twenty PMS images obtained from 2017 to 2019 were applied to analyze Chla in Bohai sea. The results show that: (1) the new built Chla inversion model PMS-1 for the GF-4 PMS sensor can extract Chla distribution details in the Bohai Sea well. The high Chla content in the Bohai Sea is mainly located in coastal areas, such as the top of Laizhou Bay, Bohai Bay and Liaodong Bay, with the value being around 13 µg/L. The concentration of Chla in the Bohai Strait and northern Yellow Sea is relatively low with the value being around 5 µg/L. (2). Taking full advantage of the continuous observation of geostationary orbit satellite, GF-4 with a high-resolution sensor PMS of 50 m can effectively detect short-term change (changes within 10 min) in Chla concentration. The changes mainly appear at the southwest and northeast costal area as well as in the center of Bohai Sea with the change value of around 3 µg/L. (3) The change of Chla concentration in the Bohai sea is related to the environmental factors such as seawater temperature, salinity, illumination and nutrient salts, as well as the dynamic factors such as wind, flow field and tidal current.


Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1762 ◽  
Author(s):  
Jiancheng Shang ◽  
Jian Sun ◽  
Lei Tao ◽  
Yuanyi Li ◽  
Zhenhua Nie ◽  
...  

The Bohai Sea is a semi-enclosed shallow sea in China, where the tides and wind are the dominant factors contributing to the water exchange with the Yellow Sea. However, existing studies on this water exchange primarily consider only the effect of tidal action, neglecting the contribution of wind. In this study, numerical models were used to simulate the hydrodynamic processes and tracer transport, with the consideration of both tides and wind. Based on the models, the two time scales, age and half-life, are applied to study the water exchange in the Bohai Sea quantitatively. The results show that the age and half-life decrease significantly when wind is included in the simulation, revealing that wind is an important contributor to the water exchange in such a semi-enclosed shallow sea. Under the combined forcing of tides and wind, the water transport in the Bohai Sea becomes clockwise, in contrast with the counterclockwise transport driven by the tides only. The seasonal-varying wind leads to a fluctuation of water exchange in an annual cycle, with the stronger water exchange in the northern (Liaodong Bay) and the western (Bohai Bay) regions of the Bohai Sea in winter and in the southern part (Laizhou Bay) in summer.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yumei Ding ◽  
Lei Ding

A hindcast of typical extratropical storm surge occurring in the Bohai Sea in October 2003 is performed using a three-dimensional (3D) Finite Volume Coastal Ocean Model (FVCOM). The storm surge model is forced by 10 m winds obtained from the Weather Research Forecasting (WRF) model simulation. It is shown that the simulated storm surge and tides agree well with the observations. The nonlinear interaction between the surge and astronomical tides, the spatial distribution of the maximum surge level, and the hydrodynamic response to the storm surge are studied. The storm surge is the interaction of the surge and the astronomical tides. The currents change rapidly during the storm surge and turn to be the unidirectional at some places where the tidal currents are usually rectilinear. The results show that the local surge current velocity in each depth, with a magnitude of the same order as the astronomic tidal currents, increases or decreases rapidly depending on the relationship between the winds and current directions. Furthermore, the current pattern gets more complicated under the influence of the direction of the winds, which might affect sand movement in the coastal water of the Bohai Sea.


2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Jianlong Feng ◽  
Delei Li ◽  
Yan Li ◽  
Qiulin Liu ◽  
Aimei Wang
Keyword(s):  

2012 ◽  
Vol 518-523 ◽  
pp. 1321-1324 ◽  
Author(s):  
An Ning Suo ◽  
Xu Bin Pan ◽  
Jian Hua Zhao ◽  
Yong Hai Yu

Since 1988, great changes of primary production, pollutants loading, coastline and sea area have happened in the Bohai Sea in China. These environmental changes increased the value of marine ecosystem services value from 529.42 billion RMB in 1988 to 558.83 billion RMB in 2010. The ecosystem services values of recreation, food and materials production, O2 supply, climate regulation and primary productivity were raised. However, other marine ecosystem services value, including biological control, pollutant purification, knowledge broaden and biodiversity protection were lowered. In addition, value of ecosystem services increased in Liaodong Bay and Bohai Bay, but decreased in middle Bohai and Bohai strait, and it no change in Laizhou Bay,.This spatial difference of ecosystem service function value was mainly caused by the change of recreation function, O2 supply function and climate regulation function.


2011 ◽  
Vol 94-96 ◽  
pp. 810-814
Author(s):  
Jin Shan Zhang ◽  
Wei Sheng Zhang ◽  
Chen Cheng ◽  
Lin Yun Sun

Bohai Bay is an semi-closed bay, the storm surge disaster is very serious in past. Now more and more large ocean engineering are built here, To study changes of storm surge induced by the construction of large-scale coastal engineering in Bohai Bay in present, 2D numerical storm surge model is established with large - medium - small model nested approach. The three most typical storms surges: 9216, 9711 and by cold wave in October 2003 are simulated in the condition of before and after implementation of planning projects in Bohai Bay. Changes of storm surge water level due to implementation of artificial projects are analysis in this paper.


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