under discussion
Created: Feb. 8, 2021
Proposer: Andy Saulter
Proposed Date: 2021-02-01
Change Date: Feb. 8, 2021, 11:46 a.m.
Term: sea_surface_wave_mean_wavenumber_from_variance_spectral_density_first_wavenumber_moment
Unit: m-1
Unit ref: UPRM
The wave directional spectrum can be written as a five dimensional function S(t,x,y,k,theta) where t is time, x and y are horizontal coordinates (such as longitude and latitude), k is wavenumber and theta is direction. S has the standard name sea_surface_wave_directional_variance_spectral_density. S can be integrated over direction to give S1= integral(S dtheta) and this quantity has the standard name sea_surface_wave_variance_spectral_density. Wavenumber is the number of oscillations of a wave per unit distance. Wavenumber moments, M(n) of S1 can then be calculated as follows: M(n) = integral(S1 k^n dk), where k^n is k to the power of n. The mean wavenumber, k(1), is calculated as the ratio M(1)/M(0).