August 2020 – TD 316 OPERATING MANUAL – Motus Wave Sensor 5729
Page 31
Orbital Ratio Spectrum, K(f)
gives the ratio of vertical to horizontal motions corrected for the wavenumber and water
depth
where:
C11(f), C22(f), and C33(f), are the cross-spectra of displacement in Vertical, East and North direction. k(f), is the wave
number and h is the water depth.
Fourier Coefficients Spectrum, A1(f), B1(f), A2(f), B2(f)
are used to calculate all frequency based parameters
Wave Peak
Direction, θ
gives the direction of the peak wave period. The wave peak direction is calculated as;
where:
is the frequency that gives the maximum energy in the specter E(f).
Wave Peak Direction Wind
is calculated using the waves defined as Wind. The range of Wind and Swell are
configurable using the
Swell Wind Separation Frequency (Hz)
parameter.
Wave Peak Direction Swell
is calculated using the waves defined as Wind. The range of Wind and Swell are
configurable using the
Swell Wind Separation Frequency (Hz)
parameter.
Wave Mean Direction
is the energy weighted mean direction over all frequency bins.
The spreading angle is a measure of how wide the directional cone is over which the wave direction is distributed
(Kumar and Anoop, 2013).
Significant Wave Height
is defined either as
H
m0
,
H
1/3
,
H
1/10
or H
1/1
; the difference in magnitude between the four
definitions is only a few percent. See definition of each parameter below.
Significant Wave Height
is equivalent to
Wave Height.
Wave Height Wind/Swell H
m0
is a modern definition of significant wave height defined as four times the standard
deviation of the surface elevation. Full name is
Significant Wave Height, Wind/Swell H
m0
Wave Height Wind H
m0
is calculated using the waves defined as Wind. The range of Wind and Swell are configurable
using the
Swell Wind Separation Frequency (Hz)
parameter. Full name is
Significant Wave Height Wind H
m0
Wave Height Swell H
m0
is calculated using the waves defines as Swell. The range of Wind and Swell are configurable
using the
Swell Wind Separation Frequency (Hz)
parameter. Full name is
Significant Wave Height Swell H
m0
