advective

Advective is an adjective describing processes in which properties are transported by the bulk motion of a fluid; the corresponding noun is advection. Advective transport is distinct from diffusive transport, which arises from random molecular motion or turbulent mixing and moves substances down gradients.

In physical and environmental sciences, advection refers to the horizontal or vertical transport of scalars such as heat, moisture, salinity, or pollutants by the fluid’s velocity field. The advective contribution to the evolution of a scalar concentration C is described by the term v · ∇C, where v is the velocity field. The governing transport equation often takes the form ∂C/∂t + v · ∇C = sources − sinks. The advective flux of C can be written as F_adv = v C (for mass transport) or, with density ρ, F_adv = ρ v C; for heat, analogous expressions use temperature or thermodynamic variables.

Advective processes are central in meteorology and oceanography. In the atmosphere, advective transport moves heat, moisture, and pollutants by wind, shaping weather patterns and fronts. In the ocean, currents advect temperature and salinity, influencing climate and ecosystem structure. In hydrology and groundwater science, advective transport describes the bulk movement of dissolved constituents with flowing water, complementing diffusion and dispersion.

Advective behavior is thus a key concept for understanding how substances and properties move in fluids, often dominating where large-scale flow carries material more effectively than gradient-driven diffusion.