Recently, the State Key Laboratory of Tropical Marine Environment (LTO) of the South China Sea Institute of Oceanography of the Chinese Academy of Sciences and a number of units inside and outside the United Nations have made new progress in the study of the mechanism of changes in the upper ocean circulation of global warming. The research was published in Science Advances.
In the context of global warming, ocean circulation changes significantly, thereby changing the redistribution of material and energy in the ocean and playing an important regulatory role in the marine environment and climate system. Therefore, the impact of global warming on ocean circulation has become a frontier and hotspot of international research. However, it is unclear what physical mechanisms global warming primarily affect ocean circulation.
Wind stress is the main driving force for the upper ocean circulation. After exhaustive numerical experiments in global ocean patterns, the study found that in the context of global warming, changes in upper ocean circulation are mainly driven by sea surface warming, while changes in wind stress play only a secondary role. The study is the first to find that the warming of the sea surface caused by global warming has a consistent acceleration trend in the upper ocean circulation in more than three-quarters of the world’s oceans. Specifically, in subtropical circulation and equatorial circulation systems, the heat absorption of seawater enhances the vertical layer of ocean density, limiting the upper circulation to a shallower layer, which in turn accelerates the upper circulation and slows down with the lower circulation. For example, the Kuroshio flow from Taiwan to Kyushu, Japan, along the continental slope of the East China Sea is part of the subtropical circulation across the North Pacific, and the acceleration of the surface layer of kuroshio caused by global warming has an important impact on the east Sea circulation and ecological environment. In addition, the study also revealed that the acceleration of the Antarctic flow around the pole is closely related to the uneven heat absorption in the north-south direction of the sea and the corresponding geostatic adjustment, confirming the results of the latest marine and satellite observations.
Figure 1. Ocean surface circulation map
Figure 2:Changes in the global oceanic upper circulation caused by sea surface warming in the context of global warming. Red arrows indicate ocean current acceleration, blue arrows indicate deceleration, and fill indicates changes in the height of the upper specific capacity
This result provides a new idea for exploring the changes of ocean circulation under the background of global warming, and has important reference significance for assessing the uncertainty of future changes in ocean circulation. (Source: South China Sea Institute of Oceanology, Chinese Academy of Sciences)
Related paper information:https://doi.org/10.1126/sciadv.abj8394