Level 3 data contains the raw (and optionally cleaned) spectra derived from level 2 time series and is saved in the NetCDF group "L3_spectra". 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
| 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
| Parameter Name |
Standard Name |
Units of measurement |
dimension
|
| TIME |
time |
CF-Conventions compatible offset[math]\displaystyle{ ^b }[/math] |
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
|
| SH_SPEC_CLEAN[math]\displaystyle{ ^a }[/math] |
shear_probe_spectrum_clean |
s-2 cpm-1 |
[TIME_SPECTRA, WAVENUMBER, N_SHEAR_SENSORS]
|
[math]\displaystyle{ ^a }[/math] SH_SPEC_CLEAN must be included in the file if these spectra were used to compute [math]\displaystyle{ \varepsilon }[/math]
[math]\displaystyle{ ^b }[/math] i.e. "Days since YYYY-MM-DDT00:00:00Z"
Optional Level 3 Variables
| Parameter Name |
Standard Name |
Units of measurement |
dimension
|
| PRES |
water_pressure |
dbar |
TIME_SPECTRA
|
| 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]
|
Return Dataset requirements for shear probes
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go to next: Level 4 data.
