The rate at which adjacent flow diverges along an axis oriented normal to the flow at the point in question; the opposite of confluence. The diffluence may be measured by ∂vn/∂n or V∂ψ/∂n, where V is the speed of the wind, the n axis is oriented 90° clockwise from the direction of the wind vector, vn is the wind component in the n direction, and ψ is the wind direction measured in degrees clockwise from a reference direction.