A study on the leeway drift characteristic of a typical fishing vessel common in the Northern South China Sea

2021 ◽  
Vol 109 ◽  
pp. 102498
Author(s):  
Sujing Meng ◽  
Wei Lu ◽  
Yun Li ◽  
Hui Wang ◽  
Lifang Jiang
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Fishing Vessel ◽  
China Sea ◽  
Leeway Drift

scholarly journals Identification of Fishing Vessel Types and Analysis of Seasonal Activities in the Northern South China Sea Based on AIS Data: A Case Study of 2018

2021 ◽  
Vol 13 (10) ◽  
pp. 1952
Author(s):  
Yanan Guan ◽  
Jie Zhang ◽  
Xi Zhang ◽  
Zhongwei Li ◽  
Junmin Meng ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Research Work ◽  
Gradient Boosting ◽  
Identification System ◽  
Fishing Vessel ◽  
China Sea ◽  
Fishing Vessels ◽  
Light Gradient

In recent years, concern has increased about the depletion of marine resources caused by the overexploitation of fisheries and the degradation of ecosystems. The Automatic Identification System (AIS) is a powerful tool increasingly used for monitoring marine fishing activity. In this paper, identification of the type of fishing vessel (trawlers, gillnetters and seiners) was carried out using 150 million AIS tracking points in April, June and September 2018 in the northern South China Sea (SCS). The vessels’ spatial and temporal distribution, duration of fishing time and other activity patterns were analyzed in different seasons. An identification model for fishing vessel types was developed using a Light Gradient Boosting Machine (LightGBM) approach with three categories with a total of 60 features: speed and heading, location changes, and speed and displacement in multiple states. The accuracy of this model reached 95.68%, which was higher than other advanced algorithms such as XGBoost. It was found that the activity hotspots of Chinese fishing vessels, especially trawlers, showed a tendency to move northward through the year in the northern SCS. Furthermore, Chinese fishing vessels showed low fishing intensity during the fishing moratorium months and traditional Chinese holidays. This research work indicates the value of AIS data in providing decision-making assistance for the development of fishery resources and marine safety management in the northern SCS.

GEOPHYSICAL RESPONSE OF THE LIUHUA CARBONATE PLATFORM IN NORTHERN SOUTH CHINA SEA

2011 ◽  
Vol 31 (4) ◽  
pp. 105-112
Author(s):  
Guangxu ZHANG ◽  
Shiguo WU ◽  
Weilin ZHU ◽  
Hesheng SHI ◽  
Duanxin CHEN
Keyword(s):  
South China Sea ◽  
South China ◽  
Carbonate Platform ◽  
Northern South China Sea ◽  
China Sea

Records of sea-level highstand over the Meghalayan age/late Holocene from uranium-series ages of beachrock in Weizhou Island, northern South China Sea

The Holocene ◽  
2021 ◽  
pp. 095968362110332
Author(s):  
Tingli Yan ◽  
Kefu Yu ◽  
Rui Wang ◽  
Wenhui Liu ◽  
Leilei Jiang
Keyword(s):  
South China Sea ◽  
Sea Level ◽  
South China ◽  
Intertidal Zone ◽  
Meteoric Water ◽  
Northern South China Sea ◽  
Water Environment ◽  
Sea Levels ◽  
China Sea ◽  
Micro Structures

Beachrock is considered a good archive for past sea-levels because of its unique formation position (intertidal zone). To evaluate sea-level history in the northern South China Sea, three well-preserved beachrock outcrops (Beigang, Gongshanbei, and Hengling) at Weizhou Island, northern South China Sea were selected to examine their relative elevation, sedimentological, mineralogical, and geochemical characteristics. Acropora branches with well-preserved surface micro-structures were selected from the beachrocks and used to determine the ages of these beachrocks via U-series dating. The results show that the beachrocks are composed of coral reef sediments, terrigenous clastics, volcanic clastics, and various calcite cements. These sediments accumulated in the intertidal zone of Weizhou Island were then cemented in a meteoric water environment. The U-series ages of beachrocks from Beigang, Gongshanbei, and Hengling are 1712–768 ca. BP, 1766–1070 ca. BP, and 1493–604 ca. BP (before 1950 AD) respectively. Their elevations are 0.91–1.16 m, 0.95–1.24 m, and 0.82–1.17 m higher than the modern homologous sedimentary zones, respectively. Therefore, we concluded that the sea-level in the Meghalayan age (1766–604 ca. BP) was 0.82–1.24 m higher than the present, and that the sea-level over this period showed a declining trend.

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