Ekman pumping
= Ekman pumping
{c}
{title2=$w_E$}
{wiki}
Spatial convergence or divergence of <Ekman transport> drives vertical motion at the base of the Ekman layer. With upward vertical coordinate,
$$
w_E=\widehat{\mathbf z}\mathbin\cdot
\nabla\times\left(\frac{\boldsymbol\tau}{\rho f}\right).
$$