Figure 1 (IMAGE) Science China Press Caption Geostrophic currents retrieved from multi-decadal hydrological observational data based on WOA18 ((a), (b), (d), (e), cm s?1) and the mean horizontal absolute velocity |u| in the upper 200 m simulated by OFES ((c), cm s?1). The black solid line in the intermediate panel (c) represents the location of each section of geostrophic currents. Please note that the interval of velocity contours in the moderately deep undercurrent areas is small. Credit ©Science China Press Usage Restrictions Use with credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.