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.
N_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)
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] This dimension is 1x1. Use, for example, for N_FFT_SEGMENTS (number_of_fft_segments), SPEC_STD (standard_deviation_uncertainty_of_shear_spectrum), and is one value for the entire analysis.
[math]\displaystyle{ ^a }[/math] i.e. "Days since YYYY-MM-DDT00:00:00Z"
[math]\displaystyle{ ^b }[/math] SH_SPEC_CLEAN must be included in the file if these spectra were used to compute [math]\displaystyle{ \varepsilon }[/math]
