The Kuroshio Current and the Gulf Stream, which are the strongest warm currents in the northern hemisphere, repeatedly warm and cool at the same time on a scale of several years to a dozen years, even though they are as far apart as about XNUMX kilometers across the North American continent. It was revealed by joint research groups such as Ochanomizu University, the University of Tokyo, and Japan Agency for Marine-Earth Science and Technology.
According to this study, the Kuroshio Current and the Gulf Stream are information on the strength of each other's currents and changes in the flow path through the north-south movement of the "westerlies jet stream," which is a strong westerly wind that exists over the mid-latitude region all year round. Is exchanged and the water temperature is synchronized.Along with this synchronization, the sea surface temperature off the east coast of Japan and the east coast of the United States repeatedly warms and cools at the same time.This phenomenon was named "boundary current synchronization".
Boundary flow synchronization has been detected and analyzed in recent years by both high-resolution satellite observations that measure sea surface temperature with infrared rays and high-resolution climate simulations that use global climate models that reproduce the atmosphere and oceans on supercomputers. Also statistically demonstrated by.
In addition, when the relationship between the changes in sea surface temperature and the atmosphere in the waters near the Kuroshio and the Gulf Stream was analyzed, it was found that the westerly jet stream tends to move north (north bias) when the two currents are warmer than normal.Based on these results, this study proposes the hypothesis that boundary current synchronization is a phenomenon in which the atmosphere and the ocean influence each other and fluctuate.
Furthermore, it was also observed that the fluctuation of the westerly jet stream accompanying the boundary flow synchronization tends to bring about abnormal weather such as intense heat as if aiming at the metropolitan area in the mid-latitude region of the northern hemisphere including Japan (1994). The heat wave of July 2018, etc.).
Understanding this phenomenon is expected to contribute to the prediction of abnormal weather and the management of fishery resources such as sardines and saury that are affected by the water temperature and flow off the eastern coast of Japan.
Paper information:[Science] The Gulf Stream and Kuroshio Current are synchronized
