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2.3.2 Wind Stress     continued...

Another dataset that has just been released is the Comprehensive Oceanographic Data Set (COADS), that is the latest (to 1992) archive of marine surface observations. Thus not only winds but also surface heat fluxes are available as an average over each month of the year until 1992 at 2 degrees 2 degrees resolution.

Climatological wind fields in the past have usually been computed from many years of ship observations, but they can also be obtained from a series of analyzed pressure or wind field outputs of weather prediction models.

To assist synoptic (i.e. at the same time or real-time) type ocean model simulations several of the weather prediction centers around the world have started to archive their analyzed and predicted pressure fields, winds and surface heat fluxes. Among these are the British Meteorological Office in Bracknell, England and the European Centre for Medium Range Weather Forecasting (ECMWF) in Reading, England. The ECMWF fluxes are available from July 1, 1985.

The US Navy at Fleet Numerical Ocean Central (FNOC) at Monterey, CA also runs an operational GCM on a daily basis covering the whole globe, the output of which is available every 6 hours in near-real time. One can obtain two sets of winds, computed by different models at two different height levels. One, at the 10m level above the surface, is computed by the (Global) Planetary Boundary Layer (PBL) model, using output fields of the global weather prediction model. The other set, winds at the 50m level, are direct outputs from the global prediction model. The surface heat flux components are all outputs of the PBL model. An example of the winds over the North Pacific for May 1993 will be shown in the next release of this chapter.

The vast majority of results to date have been obtained from models with climatological wind fields. Examples of recent global model results with these winds can be found in Semtner and Cherwin [58] and Hurlburt et al. [31].

(See exercise 7.)