Researchers discover ‘hotspots’ of rotating three-layer rotating gyre in the South China Sea

HKUST researchers discover

Geographical location and bathymetry of the South China Sea. Credit: HKUST

A research team led by Professor Jean Jianping, Director of the Hong Kong and Macau Ocean Research Center (CORE) at the Hong Kong University of Science and Technology (HKUST), made field observations and performed numerical simulations in the South China Sea. (SCS) and revealed unprecedented properties of 3D ocean motion in SCS through geophysical fluid dynamics theory.

the complex Ocean Rotation The system controls the energy conversion and water mass transport in the SCS, thus affecting biogeochemical processes, carbon budget, marine environmental health, regional climate change, and sustainable economic and social development in countries and surrounding regions, which account for about 22% of the world’s population. Studies on SCS circulation and dynamics are a foundation and an example for understanding SCS.

In the past few decades, there has been a growing global interest in ocean circulation research in the SCS. However, the scientific understanding of 3D water movement in this region is still very limited, ambiguous and sometimes misunderstood. This occurs due to a lack of observations, a lack of a reliable numerical model, and limited knowledge of the complex physical processes in the rotation of the SCS.

Until recently, based on observations, numerical simulationand inferring geophysical fluid dynamics, a research team led by Professor Gan, who is also a lead professor in the Department of Oceanography and the Department of Mathematics at Hong Kong University of Science and Technology, validated that the spin SCS has a three-layered structure, in which currents rotate counterclockwise, in Clockwise and clockwise in the upper, middle, and lower layers, respectively.

The study also found that the three-layered rotating cycles consist of dynamically active “hotspots” of intense currents along the steep continental slope surrounding the deep basin, rather than an orderly structure over the entire region as previously envisaged. Slope currents are mainly controlled by the combined effects of the monsoon, Kuroshio intrusion, and unique terrain, and are constantly modified and regulated by multiscale oceanic processes.

HKUST researchers discover

Schematic of three alternating alternating layers. Credit: HKUST

The study, which was recently published in Nature Communications, demonstrated the three-dimensional structure and physical mechanism of SCS rotation for the first time, and explained previous misunderstandings of water mass movement in this region. Based on these results, Professor Jan’s team created the WavyOcean System, a 3D simulation and visualization system for ocean circulation and biogeochemical processes in the SCS, which is validated and constrained by observations and dynamic logic.

“Because of the failure to capture the dynamic ‘hot spot’ in the marginal sea, almost all global models are unable to simulate the three-layered rotational structure and related physics in the South China Sea, even with the same space and physics,” Professor Gan says. temporal resolution. Therefore, compared to open oceanOur understanding and simulation of marginal global marine cycles, dictated by multiple factors such as seafloor topography, water exchange across straits, and dynamic multiscale processes, is more challenging than anticipated.”

“Observation is essential to ocean research. However, due to the strict spatio-temporal limitations of in situ observations, it is very difficult to understand the structure of ocean currents, especially for theoretical analysis of hemodynamic dynamics. Numerical experiments or simulated ‘observations’ are critical to ocean research, and an increasing number are adopting Of the new discoveries in the oceans now on a digital model that is rigorously validated by observations and geodynamic theory.”

As an expert in computational geophysical fluid dynamics, Professor Gann believes that numerical simulation is not a coding game for just input and output, but rather the process of creating a numerical scientific experiment and a “cool” observation. In addition to simulating and forecasting the real ocean, numerical modeling of the oceans is a key scientific tool for understanding ocean processes and phenomena and aiding in the exploration of the unknown.


Improving ocean circulation models


more information:
Jianping Gan et al, Hotspots of circulation in a large marginal sea, Nature Communications (2022). DOI: 10.1038 / s41467-022-29610-z

wavy ocean: Ocean.ust.hk:8443/SiteMapApi/new/index.jsp

the quote: Researchers Discover Three Rotating Layered ‘Hotspots’ in the South China Sea (2022, June 17) Retrieved June 19, 2022 from https://phys.org/news/2022-06-hotspots-three-layered -alternatively-rotating-Circulation.html

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