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.
| Dimension short name | description |
|---|---|
| TIME_SPECTRA | Time axis for the spectral estimates |
| WAVENUMBER | Wavenumber for spectral estimates |
| N_SHEAR_SENSORS | number of shear channels |
| N_***_SENSORS | number of *** channels (such as ACC and VIB) |
| Parameter Name | Standard Name | Units of measurement | dimension |
|---|---|---|---|
| TIME | time | Days since YYYY-MM-DDT00:00:00Z | TIME_SPECTRA |
| SECTION_NUMBER | dimensionless | 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 | WAVENUMBER |
| DOF | degrees_of_freedom_of_spectrum | - | 1 |
| 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_ACC_SPEC | shear_and_acceleration_cross-spectral_matrix | - | [TIME_SPECTRA, WAVENUMBER, N_ACCEL_SENSORS*N_SHEAR_SENSORS] |
