HR: 0800h
AN: OS41D-0505    [Abstracts]
TI: Tidal Convergence Fronts in Cook Inlet, Alaska
AU: * Li, C
EM: chunyan@skio.peachnet.edu
AF: Skidaway Institute of Oceanography, 10 Ocean Science Circle, Savannah, GA 31411
AU: Li, X
EM: xiaofeng.li@noaa.gov
AF: NOAA/NESDIS, ERA/3, WWBG ROOM 102, 5200 AUTH ROAD, CAMP SPRING, MD 20746-4304
AU: Pichel, W G
EM: william.pichel@noaa.gov
AF: NOAA/NESDIS, ERA/3, WWBG ROOM 102, 5200 AUTH ROAD, CAMP SPRING, MD 20746-4304
AB: Cook Inlet, Alaska is an extremely dynamic system, with tidal range up to 9 m, maximum current up to 12 knots, and an average maximum surface current of 3 knots. The water depth is mostly between 20 and 40 m in the upper inlet. Since Cook Inlet is elongated, the strong current system tends to generate axial convergence fronts. Synthetic Aperture Radar images from satellite RADARSAT-1 have shown frontal lines along the axial direction of Cook Inlet. These frontal lines can be more than 100 km in length. It also appears that the fronts vary in position from time to time. We hypothesize that the convergence fronts are a result of strong tidal current under the influence of strong bottom friction. The cross channel variation in bottom friction caused by significant depth variations tends to generate differences in both magnitude and phase of tidal flow. These cross channel differences in flow field can generate convergence along the channel. This hypothesis is tested with some preliminary studies using a diagnostic 2-D tidal model using realistic bathymetry. The model is driven by tidal data along Cook Inlet from NOAA stations. The model results have shown that the strong tidal current does produce significant convergence across the channel with significant depth variations. The maximum convergence calculated from the model is consistent with that from SAR images.
DE: 4275 Remote sensing and electromagnetic processes (0689)
DE: 4528 Fronts and jets
DE: 4560 Surface waves and tides (1255)
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting