87th AMS Annual Meeting

Thursday, 18 January 2007: 2:15 PM
Some OSSE issues for the coastal ocean observing system (COOS)
212B (Henry B. Gonzalez Convention Center)
Christopher N. K. Mooers, Univ. of Miami/RSMAS, Miami, FL; and D. S. Ko
The USA is beginning to develop the Integrated Ocean Observing System (IOOS) as a national priority. IOOS has a global ocean component for climate issues, etc. and a coastal ocean component (COOS) for the Exclusive Economic Zone (EEZ), extending from ca. 200 NM offshore to the head-of-tide in rivers. COOS is multidisciplinary in nature and linked to many research and societal uses. It is to be comprised of real-time observing subsystems, predictive modeling and analysis subsystems, and information management subsystems. The coastal ocean is presently under-sampled but there are promising autonomous observing system elements coming into practice; coastal ocean numerical models are rapidly becoming usefully competent; and user-friendly, real-time data streams are becoming generally available. However, there are numerous alternative observing, modeling, and data assimilation systems to consider, a situation that cries out for the conduct of Observing System Simulation Experiments (OSSEs).

The circulation, and ecosystems, of the coastal ocean are under the strong influence of the coastline morphology and the continental margin bottom topography and their various anomalies. They are also under the strong influence of atmospheric forcing, tidal forcing, boundary current forcing, and runoff from rivers, etc. These influences vary strongly from coastal region-to-coastal region; hence, one COOS design may not fit all.

As a specific example, the Straits of Florida - Florida Current - East Florida Shelf complex is considered. Predictions with the East Florida Shelf Information System (EFSIS, an implementation of the Princeton Ocean Model (POM)) a nowcast/forecast system (which is fully forced but free-running) have identified mesoscale eddies shed by the Florida Current as the prime forecast challenge in this domain; their life cycle properties are so regular that a targeted observing system may be in order. Options include strategically located bottom-mounted arrays of velocity profilers or upper-ocean profiling drifters, among other possibilities. Preparatory steps for OSSEs are outlined, including model-observation comparisons of correlation scales. The NRL Intra-Americas Sea -Navy Coastal Ocean Model (IAS-NCOM), a similar but fully data-assimilative nowcast/forecast system covering a much larger domain and a different grid, is evaluated as a candidate “nature run”.

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