Ekman spiral via complex wind w = u + i v: d^2 w/dz^2 = (i f/K) w

Ekman-spiral framework via complex-valued winds (Ekman 1905 Ark Mat Astron Fys 2, 11). Setup: steady atmospheric boundary layer under constant eddy-viscosity K and Coriolis f has -f v = K d^2 u/dz^2 + f u_g and f u = K d^2 v/dz^2 + f v_g.…