Offshore Spreading of Mississippi Waters: Pathways and Vertical Structure Under Eddy Influence
Document Type
Article
Publication Date
8-2019
Keywords
Gulf of Mexico, HYCOM, Observations, River plume
Digital Object Identifier (DOI)
https://doi.org/10.1029/2018JC014661
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.
Was this content written or created while at USF?
Yes
Citation / Publisher Attribution
JGR Oceans, v. 124, issue 8, p. 5952-5978
Scholar Commons Citation
Androulidakis, Yannis; Kourafalou, Vassiliki; Le Hénaff, Matthieu; Kang, HeeSook; Sutton, Tracey; Chen, Shuangling; Hu, Chuanmin; and Ntaganou, Nektaria, "Offshore Spreading of Mississippi Waters: Pathways and Vertical Structure Under Eddy Influence" (2019). C-IMAGE Publications. 145.
https://digitalcommons.usf.edu/cimage_pubs/145
Comments
Data used in this article are available for download:
Salinity and temperature measurements from an oceanographic glider deployed in the northeastern Gulf of Mexico, cruise DP02, August 2015
CTD data salinity, temperature, depth for Cruise DP02 R/V Point Sur in-situ deep seawater and associated fauna, August 8-22, 2015, Viosca Knoll GoM