Seawater dynamical models

Circulation models are based on the equations of motion of the geophysical fluid dynamics and on the thermodynamics of seawater. The model area is divided into finite size grid cells. The state of the ocean is described by the velocity, temperature, and salinity in each grid cell, and its time evolution can be computed from the three-dimensional model equations. To reduce the computational demands, the model ocean is usually incompressible and the vertical acceleration is neglected, the latter assumption is known as hydrostatic approximation. This removes sound waves in the ocean from the model solution. In the horizontal equations, the Boussinesq approximation is applied and small density changes are ignored except in the horizontal pressure gradient terms. This implies that such models conserve... 

Before discussing the chemical dynamics of estuarine systems it is important to briefly review some of the basic principles of thermodynamic or equilibrium models and kinetics that are relevant to upcoming discussions in aquatic chemistry. Similarly, the fundamental properties of freshwater and seawater are discussed because of the importance of salinity gradients and their effects on estuarine chemistry. 

A.G. Murray, G.A. Jackson (1993). Viral dynamics II A model of the interaction of ultraviolet light and mixing processes on virus survival in seawater. Mar. Ecol. Prog. Ser., 102,105-114. 

Fig. 14.18 Upper panel illustrates dissolved chloride concentration in pore waters collected from the summit of Hydrate Ridge during ODP leg 204 (Sites 1249, 1250, from Torres et al. 2004) and from a gravity core recovered from this area during RV SONNE expedition SO-143 (Haeckel et al. 2004). These data (panels A-C) indicate that hydrate is forming at very fast rates, so as to maintain the extremely high chloride values. Furthermore, to sustain the rapid formation rates, Torres et al. (2004) and Haeckel et al. (2004) show that methane must be supplied in the gas phase, as illustrated by the cartoon in panel. Methane solubility in seawater is too low for aqueous transport to deliver sufficient methane to form the observed hydrate deposits. D. Mass balance calculations based on a simple box model (E) indicate that the massive deposits recovered from the Hydrate Ridge summit probably formed in a period of the order of lOO s to lOOO s of years, highlighting the dynamic nature of these near-surface deposits (modified from Torres et al. 2004 and Haeckel et al. 2004).

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