Advection

The predominantly horizontal transport of an atmospheric property by the wind, e.g. moisture[?] or heat advection. Mathematically it is the operator (in z and p vertical coordinates)

<math>\mathbf{v} \cdot \nabla = u \frac{\partial}{\partial x} + v \frac{\partial}{\partial y} + w \frac{\partial}{\partial z} = u \frac{\partial}{\partial x} + v \frac{\partial}{\partial y} + \omega \frac{\partial}{\partial p}</math>.