HR: 14:10h
AN: OS53B-03 [Abstracts]
TI: Non-hydrostatic Flow Observed in an Inlet Leading to Lake Pontchartrain
AU: * Li, C C
EM: cli@lsu.edu
AF: Department of Oceanography and Coastal Sciences, Louisiana State University, Baton
Rouge, LA 70803, United States
AU: Zheng, Q
EM: quanan@atmos.umd.edu
AF: Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD
20742, United States
AU: Hou, A
EM: ahou@lsu.edu
AF: Department of Environmental Studies, Louisiana State University, Baton Rouge, LA 70803,
United States
AU: Laws, E
EM: edlaws@lsu.edu
AF: Department of Oceanography and Coastal Sciences, Louisiana State University, Baton
Rouge, LA 70803, United States
AB:
A fundamental assumption in estuarine dynamics is that the flow is hydrostatic, except for surface gravity waves.
With increased refinement of high resolution numerical models, the need for non-hydrostatic models is again
argued and such models are being developed widely. The observational aspect of this question is however rarely
visited. Here, we present such observations in a tidal inlet leading to Lake Pontchartrain and show that the flow in
the lake's inlet is non-hydrostatic. Strong upwelling and downwelling, on the order of 0.35 m/s and separated by
100 m, were repeatedly measured during flood tide using an acoustic Doppler current profiler within two 25-m
bathymetric depressions 330 m apart. The flow was un-stratified due to tidal straining. The observed vertical
acceleration can reach as high as 1.7x10-2 m/s2. The non-hydrostatic parameter was larger than 1, verifying
that the flow was indeed non-hydrostatic. The significant implication of this study is that, since estuaries and tidal
passes are numerous in coastal water, and they are places where the mixing of terrestrial water and coastal
water occurs, it is necessary to include the non-hydrostatic dynamics for relevant environmental transport
processes wherever it proves to have non-hydrostatic flows.
DE: 1872 Time series analysis (3270, 4277, 4475)
DE: 4217 Coastal processes
DE: 4235 Estuarine processes (0442)
DE: 4279 Upwelling and convergences (4964)
DE: 4512 Currents
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting