Chanhyung Jeon, D. Randolph Watts, Hong Sik Min, Dong Guk Kim, Sok Kuh Kang, Il-Ju Moon and Jae-Hun Park^*

Published in Frontiers in Marine Science, June 2022

An array of five pressure-recording inverted echo sounder (PIES) moorings spanning a distance of 420 km around the subtropical countercurrent and North Equatorial Current regions of the western Pacific detected extraordinary sea level drops from November to December 2013. In October 2013, three typhoons, namely, Danas, Wipha, and Francisco, consecutively passed east of the PIES sites, which significantly strengthened pre-existing cyclonic cold eddies to create the observed sea level drops. The typhoon-strengthened cold eddies propagated westward over approximately 1000 km for approximately 4 months and eventually met the Kuroshio offshore Taiwan. The approaching eddies interacted with the Kuroshio upstream for ~3 months and reduced the Kuroshio intensity by up to 24% in February–May 2014, the lowest record for the last 26 years of satellite measurements. Our results can provide a new mechanism linking typhoon-to-eddy-to-Kuroshio variability through oceanic processes.

Fig. Typhoon tracks (gray solid line) and intensity with Saffir–Simpson scale (color dots every 6 h). Background color indicates the sea-surface height (SSH) difference between before (October 5th, 2013) and after (October 31st, 2013) three typhoons (Danas, Wipha, and Francisco). Black solid line extending northeast of Taiwan indicates the mean Kuroshio path, and green indicates perpendicular lines to the Kuroshio path every 10 km. Red line is the Kuroshio upstream used for Kuroshio intensity estimation. Pressure-recording inverted echo sounder (PIES) mooring sites are marked with cyan triangles. Red trapezoid is the calculation region of the ocean heat content (OHC) change. PS, ECS, and ES indicate the Philippine, East China, and East Seas, respectively.

Jeon, C., Watts, D., Min, H., and et al. 2022. Weakening of the Kuroshio Upstream by Cyclonic Cold Eddies Enhanced by the Consecutive Passages of Typhoons Danas, Wipha, and Francisco (2013). Front. Mar. Sci., 9, https://doi.org/10.3389/fmars.2022.884768