![]() ![]() The free-drift model includes effects of sea surface tilt as a geostrophic current balance. The quasi-steady free drift model neglects inertia of the ice and ocean mixed layer and describes the effect of wind forcing. ![]() Tidal velocity contributions are also neglected so that daily averages of ice motions are considered. Deep ocean currents are estimated as the average of recent wind-driven model errors. Effects of ice stress divergence and other un-modeled physics are approximated using optimal estimation. This statistical component is estimated from the difference between recent ice motion observations and the deterministic components of the model. Its mean and variance are then held constant for the forecast period. The blended model is more accurate than the free-drift model that comprises its deterministic component for the test case presented here. The across-shelf structures of the ocean circulation and the associated sea surface height (SSH) variability are examined on the west Florida shelf (WFS) for the 3-yr interval from September 1998 to December 2001. Five sets of characteristic circulation patterns are extracted from 2-day, low-pass-filtered data using the self-organizing map: extreme upwelling and downwelling structures with strong. currents, asymmetric upwelling and downwelling structures with moderate currents, and a set of transitional structures with weak currents. The temporal variations of these structures are coherent with the local winds on synoptic weather time scales. On seasonal time scales they are related to both the local winds and the water density variations. The circulation is predominantly upwelling during autumn to spring months (October–April) and downwelling during summer months (June–September). Coastal sea level fluctuations are related to both the dynamical responses of the inner shelf circulation to meteorological forcing and the offshore SSH.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |