a semienclosed sea in the western part of the Pacific Ocean, along the coast of East and Southeast Asia, between the Indochinese and Malaccan peninsulas and the islands of Kalimantan (Borneo), Palawan, Luzon, and Taiwan. It is connected by Formosa Strait with the East China Sea in the north, by the Bashi Channel and Luzon Strait with the Pacific Ocean in the northeast, by Singapore Strait with the Indian Ocean in the southwest, and by Karimata and Kelasa straits with the Java Sea in the south.
The South China Sea has an area of 3.537 million sq km, an average depth of 1,024 m, and a water volume of 3.622 million cu km. The shoreline is relatively weakly indented. Major inlets are the Gulf of Tonkin and the Gulf of Siam. The shores are primarily low-lying. The sea has one large island, Hainan. There are many small islands, including Nansha, Sisha (Paracel), and Bunguran (Great Natuna). Most of the small islands are coral islands. Several large rivers empty into the South China Sea, including the Hsi Chiang, the Red River, the Mekong, and the Chao Phraya (Mae Nam or Menam).
The western and southern parts of the sea are occupied by a broad continental shelf, known as the Sunda Shelf, with depths of 30–80 m, dropping to more than 150 m at the margin. In the northeast is a deep basin, with depths of more than 4,000 m in certain depressions. The greatest depth is 5,560 m. Underwater earthquakes and volcanic eruptions are characteristic. In the deeper parts of the sea, the bottom is covered with silt; in the shallower parts, it is covered with sandy silt, with stones and pebbles in some places.
The sea has a tropical climate, with an equatorial monsoon climate in the southern part. Prevailing winds are northeasterly in the winter and southerly and southwesterly in the summer. The average February temperature ranges from 15°C in the north to 25°C in the south; the average August temperature is 27°–28°C. The region receives 2,000–2,500 mm of precipitation a year. Typhoons occur frequently in the summer and fall. A southern current is clearly marked in the western part of the sea during the winter and a northern current during the summer. Currents in the eastern part of the sea are weak and inconsistent. Current velocities are about 1 km/hr. The average surface water temperature in February ranges from 20°C in the north to 27°C in the south, often exceeding 28°C in the Gulf of Siam. August temperatures are 28°–29°C. The salinity ranges from 31.0–33.0‰ in the summer to 31.5–34.0‰ in the winter. The temperature and salinity are virtually constant at depths greater than 2,000 m, measuring 2.3°C and 34.63‰, respectively. Tides are diurnal and mixed, reaching 5.9 m.
Fish are abundant, including tuna, southern herring, sardines, mackerel, drumfish, and eels. Sea turtles and trepangs are also caught. Major ports include Bangkok (Thailand), Hsiangkang, Canton, and Shant’ou (People’s Republic of China), Ho Chi Minh and Haiphong (Vietnam), and Manila (Philippines).
A. M. MUROMTSEV