Level 4 data (shear probes)

Level 4 data include the final dissipation estimates as time series, as well as indicators for the quality and accuracy of the estimates and additional derived parameters. It is saved in the NetCDF group "L4_dissipation". Each dissipation estimate in level 4 corresponds to a spectrum in the level 3 data. Consequently, the level 3 and 4 TIME dimensions are the same. Parameter EPSI_FINAL is the final dissipation rate estimate, averaged of the selected estimates (using the QC flags) at that depth.

Dimensions

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Dimension short name	description
TIME_SPECTRA	length of the record of average times of spectral segments
N_SHEAR_SENSORS	number of shear channels (shear sensors)

Required Variables

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Parameter Name	Standard Name	Units of measurement	dimensions
TIME	time	CF-Conventions compatible offset${}^c$	TIME_SPECTRA
SECTION_NUMBER	unique_identifier_for_each_section _of_data_from_timeseries	-	TIME_SPECTRA
PSPD_REL	flow_past_sensor	m s-1	TIME_SPECTRA
EPSI	specific_turbulent_kinetic_energy_dissipation _in_water	W kg-1	[TIME_SPECTRA, N_SHEAR_SENSORS]
EPSI_FINAL	specific_turbulent_kinetic_energy_dissipation _in_water	W kg-1	TIME_SPECTRA
KMAX	maximum_wavenumber_used_for_estimating_ turbulent_kinetic_energy_dissipation	cpm	[TIME_SPECTRA, N_SHEAR_SENSORS]
EPSI_FLAGS ${}^a$	dissipation_qc_flags	-	[TIME_SPECTRA, N_SHEAR_SENSORS]
METHOD ${}^b$	method_used_for_estimating_ turbulent_kinetic_energy_dissipation	-	[TIME_SPECTRA, N_SHEAR_SENSORS]

${}^a$ Quality control coding for the final dissipation estimate.

${}^b$ METHOD=0 for spectral integration, METHOD=1 for fitting to the inertial subrange.

${}^c$ i.e. "Days since YYYY-MM-DDT00:00:00Z"

Optional Level 4 Variables

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Parameter Name	Standard Name	Units of measurement	dimension
PRES	water_pressure	dbar	TIME_SPECTRA
KVISC	kinematic_viscosity_of_water	m2 s-1	TIME_SPECTRA
FOM	figure_of_merit	-	[TIME_SPECTRA, N_SHEAR_SENSORS]
MAD	mean_absolute_deviation	-	[TIME_SPECTRA, N_SHEAR_SENSORS]
VAR_RESOLVED	variance_resolved	-	[TIME_SPECTRA, N_SHEAR_SENSORS]
KMIN	minimum_wavenumber_used_for_estimating_ turbulent_kinetic_energy_dissipation	cpm	[TIME_SPECTRA, N_SHEAR_SENSORS]
EPSI_STD	expected_standard_deviation_of_the_ logarithm_of_the_dissipation_estimate	-	[TIME_SPECTRA, N_SHEAR_SENSORS]

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