The turbulent diffusion coefficients, kz and K, being phenomenological quantities could eventually be chosen separately for temperature, A* = Tw*, and salinity, A* = Sw*, and not necessarily be identical to that used in (2.61) for momentum. If it is assumed that there are no sources or sinks of heat or salt within the ocean, the right-hand side of (2.64) may be replaced by zero. The exchange of heat and salt between the ocean and the atmosphere can then be incorporated into the boundary conditions, under which the two equations (2.64) are solved,

PwW-z total s d z

Among the chemical reaction terms that have been suggested for inclusion as source terms SA in (2.49) are e.g. the sulphate-forming reactions found in sea-salt spray particles (Laskin et al., 2003).

The surface net energy flux ESotal [cf. (2.10)], the evaporation e and precipitation r are variables which link the ocean with the atmosphere, as well as the wind stress appearing in (2.62). In (2.65), Cw is the specific heat of water.

The above expressions do not include the contributions from ice-covered water. Bryan (1969) has constructed boundary conditions allowing for formation and melting of sea ice. Pack ice extending to a depth of less than 3 m is able to move, so Bryan adds a transport equation for such sea ice in the general form of (2.64) and with a suitable source term. More recent models include a specific ice cover model and take into account both melting and sublimation processes (see e.g. NCAR, 1997).

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