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
|
| N_WAVENUMBER |
length of the wavenumber array
|
| N_SHEAR_SENSORS |
number of shear channels (shear sensors)
|
| N_***_SENSORS |
number of *** channels
|
| N_SH_ACC_SPEC |
number of shear-acceleration cross spectra
|
| N_SH_VIB_SPEC |
number of shear-vibration cross spectra
|
| N_GLOBAL_VALUES [math]\displaystyle{ ^a }[/math] |
dimension for 1 data point (for the entire analysis)
|
[math]\displaystyle{ ^a }[/math] Dimension for variables of the size 1x1 for variables such as N_FFT_SEGMENTS and DOF.
Variables
| Parameter Name |
Req.[math]\displaystyle{ ^a }[/math] |
Standard Name |
Units of measurement |
dimension
|
| TIME |
R |
time |
CF-Convention[math]\displaystyle{ ^b }[/math] |
TIME_SPECTRA
|
| SECTION_NUMBER |
R |
unique_identifier_for_each_section_ of_data_from_timeseries |
- |
TIME_SPECTRA
|
| PSPD_REL |
R |
platform_speed_wrt_[sea][math]\displaystyle{ ^c }[/math]_water |
m s-1 |
TIME_SPECTRA
|
| SH_SPEC |
R |
shear_probe_spectrum |
s-2 cpm-1 |
TIME_SPECTRA, N_WAVENUMBER, N_SHEAR_SENSORS
|
| KCYC |
R |
cyclic_wavenumber |
cpm |
TIME_SPECTRA, N_WAVENUMBER
|
| SH_SPEC_CLEAN |
R |
shear_probe_spectrum_clean |
s-2 cpm-1 |
TIME_SPECTRA, N_WAVENUMBER, N_SHEAR_SENSORS
|
| N_FFT_SEGMENTS |
R |
number_of_fft_segments |
- |
N_GLOBAL_VALUES
|
| N_VIB_SENSORS |
R |
number_of_vibration_sensors_used_for_cleaning_spectra |
- |
N_GLOBAL_VALUES
|
| SPEC_STD |
R |
standard_deviation_uncertainty_of_shear_spectrum |
- |
N_GLOBAL_VALUES
|
| PRES |
HR |
[sea][math]\displaystyle{ ^c }[/math]_water_pressure |
dbar |
TIME_SPECTRA
|
| ACC_SPEC |
O |
acceleration_sensor_spectrum |
m2 s-4 cpm-1 |
TIME_SPECTRA, N_WAVENUMBER, N_ACCEL_SENSORS
|
| VIB_SPEC |
O |
vibration_sensor_spectrum |
- |
TIME_SPECTRA, WAVENUMBER, N_VIB_SENSORS
|
| SH_VIB_SPEC |
O |
shear_and_vibration_cross-spectral_matrix |
- |
TIME_SPECTRA, N_WAVENUMBER, N_SH_VIB_SPEC
|
| SH_ACC_SPEC |
O |
shear_and_acceleration_cross-spectral_matrix |
- |
TIME_SPECTRA, N_WAVENUMBER, N_SH_ACC_SPEC
|
| DOF |
O |
degrees_of_freedom_of_spectrum |
- |
N_GLOBAL_VALUES
|
[math]\displaystyle{ ^a }[/math]: Code for the requirement of variable, R: Required, HR: Highly recommended, O: Optional
[math]\displaystyle{ ^b }[/math]: Unit and offset need to be compatible with the Climate and Forecast (CF)-convention
[math]\displaystyle{ ^c }[/math]: User can choose between water or sea_water depending on the environment
Return Dataset requirements for shear probes
go to previous: Level 2 data
go to next: Level 4 data.
