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Variability in shelf transports in the Gulf of Alaska, Part III: Observations of the Alaska Coastal Current from a moored buoy array
Nancy B. Kachel, University of Washington, Seattle, WA; and N. A. Bond, C. W. Mordy, P. J. Stabeno, and P. Sullivan
The Alaska Coastal Current (ACC) is strong coastal current that flows ~1000km along the Alaskan coast. The ACC is a buoyancy and wind driven current with an average transport of ~1.x106 m3s-1. The focus of this presentation is that region along the Kenai Peninsula and Shelikof Strait, where measurements are being collected under the auspices of GLOBEC's Coastal Gulf of Alaska Program (1999-present) and NOAA’s Fisheries Oceanography Coordinated Investigations (1984-present). Currents and water properties (temperature and salinity) are measured directly using current meters from more than dozen moorings. Along shore transport is correlated with the along-shore component of the wind (r ~ 0.6). Cross shelf transport is more difficult to determine, but the moorings together with trajectories for drifters and water properties indicate that the bathymetry play a key role. In addition, preliminary evidence indicates that some aspects of the cross-shelf and on-shelf flow are related to the winds, but not necessarily in a straightforward manner. For example, in many cases there has been a more coherent response to the cessation, rather than to the onset, of a strong forcing event. In addition, the sense and magnitude of the cross-shelf flow near the surface is not simply related to its counterpart at depth, even during periods of strong downwelling or moderate upwelling favorable winds. Nevertheless, our results suggest that the mooring observations can be used to provide useful and meaningful estimates of the ACC's response to atmospheric forcing.
Session 2, From Air to Sea
Wednesday, 6 August 2003, 3:45 PM-5:05 PM
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