Henry Charnock

Henry Charnock CBE FRS (25 December 1920 – 28 November 1997) was a British meteorologist. He is well known for his work on surface roughness and wind stress over water surfaces. The now named "Charnok's relationship" describes the aerodynamic roughness length, ${\displaystyle z_{0}}$, over a water surface by:

${\displaystyle z_{0}=Cu_{*}^{2}/g}$

where ${\displaystyle u_{*}}$ is the friction velocity and ${\displaystyle g}$ is the acceleration due to gravity (typically the Standard gravity). ${\displaystyle C}$ is Charnock's proportionality constant, shown to be 0.156.