Level 3 data (shear probes)

Level 3 data contains the raw (and optionally cleaned) spectra derived from level 2 time series. Level 3 parameters are defined along a new TIME dimension, which is the average time of the individual spectral segments. The length of the TIME dimension equals the number of spectral segments. Parameter for the calculation of the spectra, e.g. segment length, are provided in the meta data.

Dimensions

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Dimension name	description
TIME_SPECTRA	length of the record of average times of spectral segments. This also equals time of dissipation estimates.
WAVENUMBER	length of the wavenumber array
N_SHEAR_SENSORS	number of shear channels (shear sensors)
N_***_SENSORS	number of *** channels (such as ACC and VIB)

Required Variables

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Parameter Name	Standard Name	Units of measurement	dimension
TIME	time	Days since YYYY-MM-DDT00:00:00Z	TIME_SPECTRA
SECTION_NUMBER		-	TIME_SPECTRA
PSPD_REL	platform_speed_wrt_sea_water	m s-1	TIME_SPECTRA
SH_SPEC	shear_probe_spectrum	s-2 cpm-1	[TIME_SPECTRA, WAVENUMBER, N_SHEAR_SENSORS]
KCYC	Cyclic wavenumber	cpm	[TIME_SPECTRA, WAVENUMBER]
DOF	degrees_of_freedom_of_spectrum	-	1

Optional Level 3 Variables

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Parameter Name	Standard Name	Units of measurement	dimension
PRES	water_pressure	dbar	TIME_SPECTRA
SH_SPEC_CLEAN	shear_probe_spectrum_clean	s-2 cpm-1	[TIME_SPECTRA, WAVENUMBER, N_SHEAR_SENSORS]
ACC_SPEC	acceleration_sensor_spectrum	m2 s-4 cpm-1	[TIME_SPECTRA, WAVENUMBER, N_ACCEL_SENSORS]
VIB_SPEC	vibration_sensor_spectrum	-	[TIME_SPECTRA, WAVENUMBER, N_VIB_SENSORS]
SH_VIB_SPEC	shear_and_vibration_cross-spectral_matrix	-	[TIME_SPECTRA, WAVENUMBER, N_VIB_SENSORS*N_SHEAR_SENSORS]
SH_ACC_SPEC	shear_and_acceleration_cross-spectral_matrix	-	[TIME_SPECTRA, WAVENUMBER, N_ACCEL_SENSORS*N_SHEAR_SENSORS]

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