Simulation of meridional overturning in the upper layer of the South China Sea with an idealized bottom topography

2004 ◽  
Vol 49 (7) ◽  
pp. 740-746 ◽  
Author(s):  
Dongxiao Wang ◽  
Xiongbin Liu ◽  
Wenzhi Wang ◽  
Yan Du ◽  
Weidong Zhou
2020 ◽  
Vol 91 (6) ◽  
pp. 3454-3468
Author(s):  
Seongjun Park ◽  
Tae-Kyung Hong

Abstract Microseisms in frequencies of 0.05–0.5 Hz are a presentation of solid earth response to the ocean waves that are developed by atmospheric pressure change. The South China Sea provides a natural laboratory with a closed ocean environment to examine the influence of regional factors on microseism development as well as the nature of microseisms. The microseisms induced by typhoons crossing over the South China Sea are investigated. Typhoons are typical transient sources of varying strengths and locations. Primary microseisms develop nearly stationary in the northeastern South China Sea for most typhoons, suggesting effective environment for excitation of primary microseisms. Typhoon-induced secondary microseisms develop around the typhoon paths with time delays varying up to one day. Typhoon-induced microseism amplitudes are proportional to the ocean-wave amplitudes in the source regions, decaying with distance. Ocean waves develop following the typhoons for days. The dominant frequency of typhoon-induced microseisms increases with time due to the influence of dispersive ocean waves. The microseisms are affected by regional factors including crustal structures, coastal geometry, ocean depth, and ocean-bottom topography.


Ocean Science ◽  
2016 ◽  
Vol 12 (1) ◽  
pp. 335-344 ◽  
Author(s):  
Jingen Xiao ◽  
Qiang Xie ◽  
Dongxiao Wang ◽  
Lei Yang ◽  
Yeqiang Shu ◽  
...  

Abstract. We examine near-inertial variability of the meridional overturning circulation in the South China Sea (SCSMOC) using a global 1 / 12° ocean reanalysis. Based on wavelet analysis and power spectrum, we suggest that deep SCSMOC has a significant near-inertial band. The maximum amplitude of the near-inertial signal in the SCSMOC is nearly 4 Sv. The spatial structure of the signal features regularly alternating counterclockwise and clockwise overturning cells. It is also found that the near-inertial signal of SCSMOC mainly originates from the region near the Luzon Strait and propagates equatorward at a speed of 1–3 m s−1. Further analyses suggest that the near-inertial signal in the SCSMOC is triggered by high-frequency wind variability near the Luzon Strait, where geostrophic shear always exists due to Kuroshio intrusion.


2019 ◽  
pp. 67-76
Author(s):  
T. D. Leonova ◽  
M. G. Valitov ◽  
O. V. Belous

The bottom topography of the studied area of the South China Sea is characterized by an uneven distribution of depths, their sharp variations and the presence of a large number of seamounts. As a result of the research conducted, bathymetric profiles, a bathymetric map and a scheme of Faye anomalies were compiled. Geomorphological zoning was conducted. Sections of bottom distinguished by morphology were identified: 1) weakly dissected slope, steep (angles up to 15) in the upper part and more gentle (57) to the bottom of the deep-water step, 2) slope eroded by fluvial processes, 3) stepped slope, 4) chains of mountains and flat-topped hills, 5) accumulative bottom of the deep-water plain. It was established that the gravitational field as a whole reflects the complex structure of the bottom, and the local forms of the underwater relief are expressed in Faye anomalies. For elevations, zones of positive anomalies of Faye are marked, and sections of canyon-like valleys were mapped by an intense negative anomaly of the gravitational field to -60 mGal. In the process of endogenous evolution of the region, the relief became more complex. The primary endogenous continental slope was almost everywhere transformed by exogenous processes. Within the shelf, the filling of the basin led to the unification of all its projections into a single raised base. A significant role in the formation of the modern relief was played by large-scale repeated sea regressions, as a result of which the formation of the sedimentary cover was interrupted by periods of its erosion with the formation of planation surfaces. The Late Pleistocene peak of the regression (1618 thousand years BP), which caused the complete drainage of the shelf areas of the region, caused the erosion of the shelf and the movement of coarse clastic material through submarine canyons and valleys.


2016 ◽  
Vol 59 (9) ◽  
pp. 1827-1833 ◽  
Author(s):  
DongXiao Wang ◽  
JinGen Xiao ◽  
YeQiang Shu ◽  
Qiang Xie ◽  
Ju Chen ◽  
...  

2015 ◽  
Vol 12 (5) ◽  
pp. 2123-2146
Author(s):  
J. Xiao ◽  
D. Wang ◽  
Q. Xie ◽  
Y. Shu ◽  
C. Liu ◽  
...  

Abstract. The near-inertial variability of the meridional overturning circulation in the South China Sea (SCSMOC) has been analyzed based on a global 1/12° ocean reanalysis. The wavelet analysis and power spectrum of deep SCSMOC time series shows that there is a significant signal in the near-inertial band. The maximum amplitude of the near-inertial signal in the SCSMOC is nearly 4 Sv. The spatial structure of the signal features regularly alternating counterclockwise and clockwise overturning cells. It is also found that the near-inertial signal of SCSMOC mainly originates from the Luzon Strait and propagates equatorward with the speed of 1–3 m s−1. Further analyses suggest that the near-inertial signal in the SCSMOC is triggered by high-frequency wind variability near the Luzon Strait where geostrophic shear always exists due to Kuroshio intrusion.


Sign in / Sign up

Export Citation Format

Share Document