Offshore Spreading of Mississippi Waters: Pathways and Vertical Structure Under Eddy Influence

Yannis Androulidakis, Vassiliki Kourafalou, Matthieu Le Hénaff, Hee Sook Kang, Tracey Sutton, Shuangling Chen, Chuanmin Hu, Nektaria Ntaganou

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


The three-dimensional structure of the offshore export of Mississippi River (MR) waters is documented for the first time with in situ data. Numerical simulations and satellite data in the Gulf of Mexico (GoM) are also employed to study two pathways that were detected in summer of 2015, along the eastern and western sides of the Loop Current (LC). The initial formation of offshore branches was primarily due to the interaction of the anticyclonic LC and LC Eddy (which were close to the MR Delta and the Louisiana-Texas shelf-slope, respectively) with riverine waters that had been advected eastward by westerly winds (which reduced the westward buoyancy-driven currents). The interaction of anticyclonic circulation patterns with cyclones (LC Frontal Eddies) was found to influence the dynamics and structure of the branches. Thickness variability and other vertical characteristics of the brackish plumes were investigated from their origin in the northern GoM through their extension in the Straits of Florida. In particular, offshore branch thickness increased near the LC and LC Frontal Eddy fronts. The two types of pathways revealed different factors contributing to the low-salinity waters. Besides the MR input, precipitation contributed to the eastern pathway, while waters from additional northern GoM rivers contributed to the western pathway. The study offers new insights on the processes that control the formation and the offshore (southward) advection of low-salinity waters. These processes have implications on the properties of waters hundreds of kilometers from the northern river sources, extending to the southern Gulf and the Straits of Florida.

Original languageEnglish (US)
Pages (from-to)5952-5978
Number of pages27
JournalJournal of Geophysical Research: Oceans
Issue number8
StatePublished - Aug 1 2019


  • Gulf of Mexico
  • Observations
  • River plume

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Oceanography


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