Kourafalou Vassiliki H.

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Vassiliki H.

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Now showing 1 - 4 of 4
  • Article
    Physical characteristics and evolution of a long-lasting mesoscale cyclonic eddy in the Straits of Florida
    (Frontiers Media, 2022-03-30) Zhang, Yingjun ; Hu, Chuanmin ; Kourafalou, Vassiliki ; Liu, Yonggang ; McGillicuddy, Dennis J. ; Barnes, Brian B. ; Hummon, Julia M.
    Ocean eddies along the Loop Current (LC)/Florida Current (FC) front have been studied for decades, yet studies of the entire evolution of individual eddies are rare. Here, satellite altimetry and ocean color observations, Argo profiling float records and shipborne acoustic Doppler current profiler (ADCP) measurements, together with high-resolution simulations from the global Hybrid Coordinate Ocean Model (HYCOM) are used to investigate the physical and biochemical properties, 3-dimensional (3-D) structure, and evolution of a long-lasting cyclonic eddy (CE) in the Straits of Florida (SoF) along the LC/FC front during April–August 2017. An Angular Momentum Eddy Detection Algorithm (AMEDA) is used to detect and track the CE during its evolution process. The long-lasting CE is found to form along the eastern edge of the LC on April 9th, and remained quasi-stationary for about 3 months (April 23 to July 15) off the Dry Tortugas (DT) until becoming much smaller due to its interaction with the FC and topography. This frontal eddy is named a Tortugas Eddy (TE) and is characterized with higher Chlorophyll (Chl) and lower temperature than surrounding waters, with a mean diameter of ∼100 km and a penetrating depth of ∼800 m. The mechanisms that contributed to the growth and evolution of this long-lasting TE are also explored, which reveal the significant role of oceanic internal instability.
  • Article
    Preparedness, planning, and advances in operational response
    (Oceanography Society, 2021-06-03) Westerholm, David G. ; Ainsworth, Cameron H. ; Barker, Christopher H. ; Brewer, Peter G. ; Farrington, John W. ; Justić, Dubravko ; Kourafalou, Vassiliki H. ; Murawski, Steven A. ; Shepherd, John G. ; Solo-Gabriele, Helena M.
    During the last 50 years, the numbers and sizes of oil spills have been significantly reduced through prevention. But spills still occur, and it is critical to prepare for these events through planning and exercises. Operational decisions are designed to expedite cleanup and minimize overall impacts, yet they often involve complex trade-offs between a multitude of competing interests. It is imperative to apply the best technology and science when events occur. However, while planning and response tactics have evolved over time, determining what may be most at risk is often confounded by sparse background data, modeling limitations, scalability, or research gaps. Since 2010, the Gulf of Mexico Research Initiative (GoMRI) and other oil spill research helped address many issues and propelled advances in spill modeling. As a result, there is an increased understanding of environmental impacts, how to assess damages, and the unintended consequences of spill countermeasures. The unprecedented amount of information resulting from this research has strengthened the bridge between the academic community and operational responders and brought improvements in preparedness, planning, and operations. This paper focuses primarily on GoMRI research and advances that relate to operational activities, as well as limitations and opportunities for gap-filling future research.
  • Article
    Bio‐optical, physical, and chemical properties of a loop current eddy in the Gulf of Mexico
    (American Geophysical Union, 2023-02-25) Zhang, Yingjun ; Hu, Chuanmin ; Barnes, Brian B. ; Liu, Yonggang ; Kourafalou, Vassiliki H. ; McGillicuddy, Dennis J. ; Cannizzaro, Jennifer P. ; English, David C. ; Lembke, Chad
    Multi‐sensor data collected with in situ and satellite instruments during August 2015 were used to understand how the three‐dimensional bio‐optical properties of a Loop Current Eddy (LCE) in the Gulf of Mexico (GoM) contrast those of the background waters, and how these properties are related to physical and chemical properties. With a surface radius of ∼150 km and vertical extension to 1,400–1,500 m, the LCE was found to have highly stratified waters in two layers, with one lying just below the mixed layer (16 m) and the other coinciding with the pycnocline (∼120–200 m within the eddy). Strong contrasts were found in the bio‐optical properties (chlorophyll‐a concentration, absorption of particulate and dissolved matters, particulate backscattering, and beam‐c attenuation) across the eddy core, eddy edge, and surrounding waters. Absorption coefficients (400 nm) of surface particulate and dissolved matters were ∼4 times higher in the surrounding waters than in the eddy core, while surface reflectance (400 nm) in the eddy core was ∼7 times higher than in the surrounding waters. The magnitude of deep chlorophyll maximum (DCM) was comparable (0.3–0.33 mg/m3) in all waters, but the depth of DCM in the eddy core (∼115 m) was much deeper than in the surrounding waters (60–75 m). These contrasts were found to correspond to different water masses with different physical (temperature, density, and buoyancy frequency) and chemical properties (salinity and dissolved oxygen concentration), where physical processes (river plume advection and eddy‐induced downwelling) appeared to drive the changes in bio‐optical properties.
  • Dataset
    Multispecies larval otolith increment data from samples collected on R/V F.G. Walton Smith cruises WS0714, WS0720, WS0809 in the Straits of Florida from 2007-2008 (FK Population Connectivity project)
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2021-12-28) Cowen, Robert K. ; Kourafalou, Vassiliki ; Paris-Limouzy, Claire B. ; Sponaugle, Su
    Multispecies larval otolith increment data from samples collected on R/V F.G. Walton Smith cruises WS0714, WS0720, WS0809 in the Straits of Florida from 2007-2008. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/529658