The paper reviews observations of wind stress and wind profiles over oceans and continents, finding consistency with Charnock's relation between aerodynamic roughness length and friction velocity. The von Kármán constant is estimated to be 0.41 ± 0.025. For practical purposes, a neutral drag coefficient (referred to 10 m) can be approximated by either a power law or a linear form over the range 4 < V < 21 m s-1. Recent turbulence sensor comparison experiments suggest that data scatter in CDN(V) plots is mainly due to calibration uncertainties. Over land, vertical momentum transfer can be described using an effective roughness length or geostrophic drag coefficient, which incorporates both friction and form drag. Low relief topography and low mountains require a geostrophic drag coefficient of approximately 3 × 10^-3, while general land surfaces require a coefficient of approximately 2 × 10^-3, with a corresponding neutral drag coefficient of approximately 10 × 10^-3 and an effective aerodynamic roughness length of approximately 0.2 m. These values satisfy the requirement of global angular momentum balance.The paper reviews observations of wind stress and wind profiles over oceans and continents, finding consistency with Charnock's relation between aerodynamic roughness length and friction velocity. The von Kármán constant is estimated to be 0.41 ± 0.025. For practical purposes, a neutral drag coefficient (referred to 10 m) can be approximated by either a power law or a linear form over the range 4 < V < 21 m s-1. Recent turbulence sensor comparison experiments suggest that data scatter in CDN(V) plots is mainly due to calibration uncertainties. Over land, vertical momentum transfer can be described using an effective roughness length or geostrophic drag coefficient, which incorporates both friction and form drag. Low relief topography and low mountains require a geostrophic drag coefficient of approximately 3 × 10^-3, while general land surfaces require a coefficient of approximately 2 × 10^-3, with a corresponding neutral drag coefficient of approximately 10 × 10^-3 and an effective aerodynamic roughness length of approximately 0.2 m. These values satisfy the requirement of global angular momentum balance.