Advection module

Kumar, S., and Homsy, G. M., Chaotic advection in creeping flow of viscoelastic fluids between slowly modulated eccentric cylinders. Phys. Fluids 8,1774-1787 (19%). 

SCRAM (28) is a TDE dynamic, numerical finite difference soil model, with a TDE flow module and a TDE solute module. It can handle moisture behavior, surface runoff, organic pollutant advection, dispersion, adsorption, and is designed to handle (i.e., no computer code has been developed) volatilization and degradation. This model may not have received great attention by users because of the large number of input data required. 

The current version of GEM-AQ has five size-resolved aerosols types, viz. sea salt, sulphate, black carbon, organic carbon, and dust. The microphysical processes which describe formation and transformation of aerosols are calculated by a sectional aerosol module (Gong et al. 2003). The particle mass is distributed into 12 logarithmically spaced bins from 0.005 to 10.24 pm radius. This size distribution leads to an additional 60 advected tracers. The following aerosol processes are accounted for in the aerosol module nucleation, condensation, coagulation, sedimentation and dry deposition, in-cloud oxidation of SO2, in-cloud scavenging, and below-cloud scavenging by rain and snow. 

Upper canopy layer The dominant term in the upper canopy is the effect on the sink of the velocity perturbation through the last term of (5.27), r/2Lc [AuCB. Since Ail peaks at the hillcrest, this produces a minimum in Ac there. This effect can be interpreted as the canopy counterpart of the dominant role played by changes in surface stress on a rough hill in modulating the surface flux boundary condition, and thereby Ac, as discussed earlier. Hence, as a result of quite different dynamics, the dominant influences on Ac in the lower and upper canopy layers are in phase leading to a minimum in Ac at the hillcrest. This simple picture is modulated by other effects in the upper canopy layer, however. The eddy flux divergence couples the upper canopy to the shear stress layer above where advection is important at first order (5.26) and within which the contributions to Ac that are caused by canopy dynamics must decay to match the inviscid, streamline convergence effects around z = hi. 

Water column optics and penetration of UVR Modulation of UVR exposure and effects by vertical mixing and advection... 

Operator splitting methods require less computational resources but demand more thought. In general, stability is not guaranteed. However, operator splitting encourages modular models and allows the use of the best available numerical technique for each module. Thus advection, kinetics, cloud processes, and aerosol processes each reside in different modules. Techniques used for these subproblems will be outlined subsequently. For applications in other problems, the reader is referred to Oran and Boris (1987). 

The model has a reactive module, which solves reaction kinetics and equilibrium reactions, and a transport module, which incorporates the advection-dispersion equation. The transport/reaction equation is formulated for each redox acceptor in the fluid phase as follows... 

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