text: It is defined as:
  - where D is a characteristic (usually vertical) length scale of a phenomenon; &nu;, the kinematic eddy viscosity; &Omega;, the angular velocity of planetary rotation; and &phi;, the latitude. The term 2 &Omega; sin &phi; is the Coriolis frequency.
  It is given in terms of the kinematic viscosity, &nu;; the angular velocity, &Omega;; and a characteristic length scale, L.
  There do appear to be some differing conventions in the literature.
  Tritton gives:
  In contrast, the NRL Plasma Formulary gives:
  where Ro is the Rossby number and Re is the Reynolds number.
  These equations can generally not be used in oceanography. An estimation of the viscous terms of Navier-Stokes equation (with eventually the Eddy Viscosity) and of the Coriolis terms needs to be done.