Observed strong currents under global tropical cyclones

Global TC's locations color coded with Saffir–Simpson Scale from JTWC (1979–2013) and NHC (1979–2013).

Global TC's locations color coded with Saffir–Simpson Scale from JTWC (1979–2013) and NHC (1979–2013).

TitleObserved strong currents under global tropical cyclones
Publication TypeJournal Article
Year of Publication2016
AuthorsChang Y.C, Tseng R.S, Chu P.C, Chen J.M, Centurioni LR
JournalJournal of Marine Systems
Date Published2016/07
Type of ArticleArticle
ISBN Number0924-7963
Accession NumberWOS:000375506200003
KeywordsClimatology; drifters; flows; hurricane; intensity; Northern Hemisphere; ocean currents; ocean response; pacific; south china sea; Southern Hemisphere; strait; surface currents; SVP drifter; Translation speed; tropical cyclones

Global data from drifters of the Surface Velocity Program (Niiler, 2001) and tropical cyclones (TCs) from the Joint Typhoon Warning Center and National Hurricane Center were analyzed to demonstrate strong ocean currents and their characteristics under various storm intensities in the Northern Hemisphere (NH) and in the Southern Hemisphere (SH). Mean TC's translation speed (U-h) is faster in the NH (similar to 4.7 m s(-1)) than in the SH (similar to 4.0 m s(-1)), owing to the fact that TCs are more intense in the NH than in the SH. The rightward (leftward) bias of ocean mixed-layer (OML) velocity occurs in the NH (SH). As a result of this slower Uh and thus a smaller Froude number in the SH, the flow patterns in the SH under the same intensity levels of TCs are more symmetric relative to the TC center and the OML velocities are stronger. This study provides the first characterization of the near-surface OML velocity response to all recorded TCs in the SH from direct velocity measurements. (C) 2016 Elsevier B.V. All rights reserved.

Short TitleJ. Mar. Syst.

To the best of our knowledge, the present study successfully provides a first statistical, spatial characterization of near-surface velocity response to all recorded tropical cyclones (TCs) in the Southern Hemisphere (SH), which is in agreement with the theoretical prediction. Overall, our results show what an average hurricane response looks like, nicely complementing other efforts that highlight the effect of the initial ocean state.

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