HR: 1340h
AN: NG43A-0438    [Abstracts]
TI: Ocean Current Spatial Patterns from West Florida Shelf velocity Time Series Using the Self-organizing Map
AU: * Liu, Y
EM: yliu@marine.usf.edu
AF: College of Marine Science, University of South Florida, 140 7th Ave South, St. Petersburg, FL 33701 United States
AU: Weisberg, R H
EM: weisberg@marine.usf.edu
AF: College of Marine Science, University of South Florida, 140 7th Ave South, St. Petersburg, FL 33701 United States
AB: A neural network analysis based on the Self-Organizing Map (SOM) is used to examine patterns of the ocean current variability on the West Florida Shelf from time series of moored velocity data that span the three-year interval from October 1999 to September 2001. Three characteristic spatial patterns are extracted in the 3$\times$4 SOM array: spatially coherent southeastward and northwestward flows with strong currents, and a transition pattern of weak currents. On synoptic weather time scale the variations of these patterns are coherent with the local winds. On seasonal time scale the variations of the patterns are coherent with both the local winds and complementary SST patterns. The currents are predominantly southeastward during winter months (from October to March) and northwestward during summer months (June through September). The spatial patterns extracted by the (nonlinear) SOM method are asymmetric, a feature that is not captured by the (linear) Empirical Orthogonal Function method. Thus, we find: (1) southeastward currents are generally stronger than northwestward currents, (2) the coastal jet axis is located further offshore for southeastward currents relative to northwestward currents, and (3) the velocity vector rotations with depth are larger when the currents are southeastward than when they are northwestward.
DE: 9820 Techniques applicable in three or more fields
DE: 4219 Continental shelf processes
DE: 4279 Upwelling and convergences
DE: 4508 Coriolis effects
DE: 4512 Currents
SC: Nonlinear Geophysics [NG]
MN: 2004 AGU Fall Meeting