Record Label : sea_surface_wave_mean_period_from_variance_spectral_density_second_frequency_moment
Record Title : Sea Surface Wave Mean Period from Variance Spectral Density Second Frequency Moment
CF Standard Name : sea_surface_wave_mean_period_from_variance_spectral_density_second_frequency_moment
Record Description : The wave directional spectrum can be written as a five dimensional function S(t,x,y,f,theta) where t is time, x and y are horizontal coordinates (such as longitude and latitude), f is frequency 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. Frequency moments, M(n) of S1 can then be calculated as follows: M(n) = integral(S1 f^n df), where f^n is f to the power of n. The second wave period, T(m2) is calculated as the square root of the ratio M(0)/M(2).
Canonical Units : s