Sea level change and beach process — A case study in south Zhejiang beach - |
| |
Authors: | Wang Baocan Jin Qingxiang Lao Zhisheng |
| |
Institution: | (1) Institute of Estuarine and Coastal Research, East China Normal University, Shanghai, China |
| |
Abstract: | This paper describes changes in sea level off the coast of China in history and at present. The evidence concerning low sea
level during the last glacial phase, Holocene marine transgression which was discovered from sea bottom in East China Sea
and China's bordering seas, and their adjacent coastal areas, where, by drilling, relic sediment, peat deposite, and mollusc
shell fossils have been obtained, and their dates are deduced through measurement of radiocarbon (C14), identified that low sea level about 15000 years ago stood in the depth of 150 m below the present level in East China Sea,
and that the subsequent transgression carried the sea up to the present sea level 6000 years ago, when the present China's
coast and other continent's coasts were outlined.
Due to a number of factors, the sea level oscillates seasonally in the border sea of China. Averagely speaking, the annual
range of the seasonal changes in sea level is about 35 m off the south Zhejiang coast, where the highest value of 20 cm occurs
in September, and the lowest of-15 cm occurs in March. The reason may be mainly due to the seasonal variations of climate
and river run-off, as well as the Taiwan Warm Current. Similar seasonal oscillations in sea level also occur in Bohai Gulf,
Yellow Sea, East China Sea and the South China Sea.
The beach process of south Zhejiang is strongly affected by the seasonal oscillations in sea level. The width of beach is
4 to 6 km, the slope is approximately in 1 : 1000. If the sea level rises or falls 1 cm, the beach submergence or emergence
is led to be about 10 m in width. As a result, the relative equilibrium of beach will be changed by the seasonal oscillations
in sea level. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|