"The hope is that comprehensive ocean models in combination with the spare in situ and the relatively abundant remotely sensed data provide the best means of studying and monitoring the oceans. Herein lies the importance and the promise of ocean models. For estimating the future state of the oceans, i.e., for prediction purposes, numerical ocean models are quite indispensable" (Kantha and Clayson, 2000).
No single model is going to be the best one for all applications. It is not a "one-size-fits-all" type of problem. The coastal ocean has shorter time scales than the deep ocean, and the bottom boundary layer and coastal boundaries are obviously more important factors for the former.
The type of model best suited to a given application depends not only on the region of interest, but also on the time scales and processes of interest. As an extreme example, a model that may be perfectly adequate for predicting tidal currents in a coastal region over the next 24-36 hours, may not be useful for predicting sea level rise over the next 100 years in the same region.
There are numerous Naval operations that may require a nowcast or forecast of currents, for example:
Some environmentally-related warfare questions
| ASW |
Can I detect and neutralize or avoid submarine threats?
What is the 3-D sound speed structure for input into my TDAs? |
| MIW |
Can I detect and neutralize or avoid mines and minefields?
Are the currents too strong for UDT swimmers? Where might drfiting mines go or come from? Can I adjust my EM sweep width based on water properties? |
| NSW |
Can I perform safe, timely and covert ingress and egress?
Are the currents too strong for swimmers or SDVs? Can I take advantage of tide height and currents? What's my survivability time in the water? |
Scenario: During a Fleet Battle Exercise, a pallet was dropped in 20m of water during a resupply operation at 26oN, 35oE on 12 September 2002 at 0200Z. A call comes in to the regional METOC center requesting guidance on which way the pallet will drift over the next 10 hours given that it is neutrally buoyant. Upon further questioning, you find that the pallet is expected to float at about 10m depth. How would you proceed? What products would you look at? Would you know if there is tidal forcing included in the products you are looking at? How about wind forcing? Could you estimate the shear between the surface and 10m depth? Could you tell how the currents change direction over the 10 hours the pallet has been in the water?
After you have completed this course, you should know how to proceed in situations that arise such as the one above. And while you won't recall all the details of each of the models described in this course, you will learn which models or products may or may not be appropriate to be used in a particular situation.
Continue on to the first module: Basics Concepts in Physical Oceanography