Spatio-temporal characteristics of the sea-ice volume of the Bohai Sea, China, in winter 2009/10

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%.

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

Water ◽

10.3390/w12051509 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1509

Author(s):

Yuanyi Li ◽

Huan Feng ◽

Guillaume Vigouroux ◽

Dekui Yuan ◽

Guangyu Zhang ◽

...

Keyword(s):

Storm Surge ◽

Bohai Sea ◽

Storm Surges ◽

Wave Force ◽

Laizhou Bay ◽

Bohai Bay ◽

Coastal Regions ◽

The Bohai Sea ◽

Tidal Phase ◽

Set Up

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.

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Estimating submarine groundwater discharges of the Bohai Sea, China using radium, hydrogen and oxygen isotopes and salinity

10.5194/egusphere-egu2020-6644 ◽

2020 ◽

Author(s):

Hailong Li ◽

Xiaolang Zhang ◽

Xuejing Wang ◽

Kai Xiao ◽

Yan Zhang ◽

...

Keyword(s):

Steady State ◽

Mass Balance ◽

River Water ◽

Bohai Sea ◽

Balance Model ◽

Laizhou Bay ◽

Bohai Bay ◽

Fresh Groundwater ◽

The Bohai Sea ◽

Submarine Groundwater

With an area of about 77,000 km2, the Bohai Sea includes three bays: Laizhou Bay, Bohai Bay and Liaodong Bay. In this study, 228Ra, &#948;D, &#948;18O 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 &#948;D, &#948;18O, and salinity in surface water in the entire Bohai Sea and &#948;D-salinity relations, the marine hydrological processes were investigated and the members of river water and groundwater for &#948;D and &#948;18O were determined. The steady-state mass-balance models of &#948;D, &#948;18O 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 228Ra is used to estimate submarine groundwater discharges of the entire Bohai Sea and its three bays.

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Suitability of locations in the Bohai Sea, China, for the exploitation of sea ice as a freshwater resource

Annals of Glaciology ◽

10.3189/2013aog62a304 ◽

2013 ◽

Vol 54 (62) ◽

pp. 267-272 ◽

Cited By ~ 2

Author(s):

Lantao Li ◽

Wei Gu ◽

Chengyu Liu ◽

Yingjun Xu ◽

Jinlong Chao ◽

...

Keyword(s):

Sea Ice ◽

Bohai Sea ◽

Mining Area ◽

Bohai Bay ◽

Liaodong Bay ◽

Gis Technology ◽

The Bohai Sea ◽

Freshwater Resource ◽

The Status ◽

Technological Level

AbstractBased on recent studies on sea ice and newly developed technologies, this paper examines the requirements and environmental factors for exploitation of sea ice as a freshwater resource. Considering the ‘mining’ of sea ice, the suitability of locations in the Bohai Sea, China, for exploitation was analysed and evaluated using GIS technology. The ice must be >10 cm thick, the intertidal zone must be narrow and the ‘mining’ area must have a water depth of at least 2 m. The sea areas with feasible resources are located mainly in the nearshore area of northern Liaodong Bay and in a narrow and long area along the coast of Bohai Bay. Most coastal areas of northern Liaodong Bay have favourable conditions, while Bohai Bay is widely constrained by unsuitable conditions. According to the status of the resources and the coastal environment conditions, the eastern and western coasts of northern Liaodong Bay are the most suitable areas for exploitation at the current technological level.

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Geosynchronous Satellite GF-4 Observations of Chlorophyll-a Distribution Details in the Bohai Sea, China

Sensors ◽

10.3390/s20195471 ◽

2020 ◽

Vol 20 (19) ◽

pp. 5471

Author(s):

Lina Cai ◽

Juan Bu ◽

Danling Tang ◽

Minrui Zhou ◽

Ru Yao ◽

...

Keyword(s):

Chlorophyll A ◽

Bohai Sea ◽

Seawater Temperature ◽

Remote Sensing Data ◽

Geosynchronous Orbit ◽

Laizhou Bay ◽

Bohai Bay ◽

The Bohai Sea ◽

Dynamic Factors ◽

Chla Concentration

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.

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Spatial distribution characteristics of sea-ice-hazard risk in Bohai, China

Annals of Glaciology ◽

10.3189/2013aog62a303 ◽

2013 ◽

Vol 54 (62) ◽

pp. 73-79 ◽

Cited By ~ 15

Author(s):

Wei Gu ◽

Chengyu Liu ◽

Shuai Yuan ◽

Ning Li ◽

Jinlong Chao ◽

...

Keyword(s):

Spatial Distribution ◽

Sea Ice ◽

Bohai Sea ◽

Hazard Index ◽

Bohai Bay ◽

Distribution Characteristics ◽

The Bohai Sea ◽

Hazard Risk ◽

Spatial Distribution Characteristics ◽

Marine Navigation

AbstractSea-ice hazard causes serious harm to aquaculture, marine navigation, offshore oil production and other activities in the Bohai Sea, China. To study the spatial distribution characteristics of sea-ice-hazard risk in Bohai is therefore desirable. The thickness and area of sea ice in the Bohai Sea during the winters (December–March) of 1987–2011 were estimated using data from the NOAA (US National Oceanic and Atmospheric Administration) satellite. The sea-ice thickness was converted into a sea-ice-hazard index after defining this index, and the different sea-ice-hazard risk grades were classified. The occurrence probability of sea-ice hazard was also calculated using fuzzy risk theory, and the spatial distribution characteristics of sea-ice-hazard risk in the Bohai Sea were studied. The results show that the sea-ice-hazard risk for offshore aquaculture decreased as the offshore distance increased. All the oilfields in Liaodong Bay are influenced by sea-ice hazard, two of the fields in Bohai Bay are slightly affected and the remaining fields are not influenced. The risk for marine navigation is related to the location of the port and the distance from the port. The risk in the port area is the highest; it is reduced by more than 30% at distances 10 km away from the port.

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Spatio-temporal characteristics of ship activities in the Bohai Sea based on GIS and AIS

地理科学进展 ◽

10.18306/dlkxjz.2020.07.010 ◽

2020 ◽

Vol 39 (7) ◽

pp. 1172-1181

Author(s):

Renli CHEN ◽

Yiqiang WANG ◽

Baijing LIU ◽

Meng GONG ◽

Xiaoqing WU ◽

...

Keyword(s):

Bohai Sea ◽

Temporal Characteristics ◽

The Bohai Sea ◽

Spatio Temporal

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Combined Effect of Tides and Wind on Water Exchange in a Semi-Enclosed Shallow Sea

Water ◽

10.3390/w11091762 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1762 ◽

Cited By ~ 5

Author(s):

Jiancheng Shang ◽

Jian Sun ◽

Lei Tao ◽

Yuanyi Li ◽

Zhenhua Nie ◽

...

Keyword(s):

Half Life ◽

Water Exchange ◽

Bohai Sea ◽

Numerical Models ◽

The Yellow Sea ◽

Laizhou Bay ◽

Bohai Bay ◽

Tracer Transport ◽

Shallow Sea ◽

The Bohai Sea

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.

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