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

Authors

Yannis Androulidakis, University of Miami
Vassiliki Kourafalou, University of Miami
Matthieu Le Henaff, University of Miami; National Oceanic and Atmospheric Administration
HeeSook Kang, University of Miami
Tracey Sutton, Nova Southeastern UniversityFollow
Shuangling Chen, University of South Florida
Chuanmin Hu, University of South Florida
Nektaria Ntaganou, University of Miami

ORCID

0000-0002-5280-7071

Document Type

Article

Publication Title

Journal of Geophysical Research: Oceans

ISSN

2169-9291

Publication Date

8-4-2019

Keywords

Gulf of Mexico, HYCOM, Observations, River plume

Abstract

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.

DOI

10.1029/2018JC014661

Comments

©2019. American Geophysical Union. All Rights Reserved.

Additional Comments

Gulf of Mexico Research Initiative grant #s: GOMA23160700, DEEPEND: GOMRI2014‐IV‐914; NASA grant #: NNX14AL98G; NOAA grant #s: NA17NOS4510099, NA15OAR4320064, NA15NOS4510226, NA11NOS4780045

NSUWorks Citation

Yannis Androulidakis, Vassiliki Kourafalou, Matthieu Le Henaff, HeeSook Kang, Tracey Sutton, Shuangling Chen, Chuanmin Hu, and Nektaria Ntaganou. 2019. Offshore Spreading of Mississippi Waters: Pathways and Vertical Structure Under Eddy Influence .Journal of Geophysical Research: Oceans . https://nsuworks.nova.edu/occ_facarticles/1048.