DOI: 10.1029/2017JC013624
Scopus记录号: 2-s2.0-85052844496
论文题名: Water Column Stability and the Role of Velocity Shear on a Seasonally Stratified Shelf, Mississippi Bight, Northern Gulf of Mexico
作者: Dzwonkowski B. ; Fournier S. ; Park K. ; Dykstra S.L. ; Reager J.T.
刊名: Journal of Geophysical Research: Oceans
ISSN: 21699275
出版年: 2018
卷: 123, 期: 8 起始页码: 5777
结束页码: 5796
语种: 英语
英文关键词: Gulf of Mexico
; Mississippi Bight
; near-inertial oscillations
; shear
; stratification
; water column stability
英文摘要: Water column stability is a critical component of coastal systems, regulating the vertical exchange of momentum, mass, and biogeochemical constituents. Observations of water column velocity and hydrographic conditions during the summer of 2010 were used to investigate aspects of the region of freshwater influence in the Mississippi Bight. Conductivity-temperature-depth surveys south of Mobile Bay indicated strong stratification (peak buoyancy frequencies ~0.09–0.3 s−1) across the inner and midshelf. Despite this strong stratification, mooring data from the 20-m isobath indicated that the bulk Richardson numbers (Ri) can span 3 orders of magnitude, O(1–100). Examination of the high-frequency (hourly) shear and buoyancy frequency time series revealed downwelling conditions, and near-inertial oscillations were primarily responsible for generating instances of relatively low stability (bulk Ri < 1). Periods of intense near-inertial oscillations also intermittently drove synthetic gradient Ri to critical or near-critical levels within the pycnocline. While the near-inertial oscillations were dominated by a clockwise rotating two-layer structure, there was also a secondary three-layer structure, both of which interacted with the low-frequency upwelling to produce highly variable vertical structuring of the horizontal velocity. The resulting velocity shear on water column stability may have important implications for shelf hypoxia during the stratified season in the Mississippi Bight. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113316
Appears in Collections: 气候减缓与适应
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作者单位: Department of Marine Sciences, University of South Alabama, Dauphin Island, AL, United States; Dauphin Island Sea Lab, Dauphin Island, AL, United States; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States; Department of Marine Sciences, Texas A&M University at Galveston, Galveston, TX, United States
Recommended Citation:
Dzwonkowski B.,Fournier S.,Park K.,et al. Water Column Stability and the Role of Velocity Shear on a Seasonally Stratified Shelf, Mississippi Bight, Northern Gulf of Mexico[J]. Journal of Geophysical Research: Oceans,2018-01-01,123(8)