Level 2 data (shear probes)

Level 2 data, that is saved in the NetCDF group "L2_cleaned", are the full resolution, cleaned and despiked parameters from level 1. The initial data set is subdivided in sections and labeled accordingly in the parameter SECTION_NUMBER with integers. Level 2 data is ready for estimating spectra. In addition to cleaned and despiked level 1 data channels, level 2 data comprises the additional parameter summarized in the table below.

It is important that the platform speed with respect to water, as used in the dissipation estimates, is included in this level. Also note that the shear probe time series (and optionally acceleration and vibration) must be cleaned and filtered as needed at this level, and will not be altered further when estimating dissipation rates.

Dimensions

Dimension short name	description
TIME [math]\displaystyle{ ^a }[/math]	length of the record from turbulence (fast) data channels
N_SHEAR_SENSORS	number of shear channel (shear sensors)
N_***_SENSORS [math]\displaystyle{ ^b }[/math]	number of *** channel (sensors)

[math]\displaystyle{ ^a }[/math] At this level platform speed must be provided. We require that this is given at the shear probe time (not TIME_SLOW or TIME_CTD. Please interpolate if needed.
[math]\displaystyle{ ^b }[/math] Please use these examples for related sensors, e.g.:
N_VIB_SENSORS for vibration (piezo-acceleration) sensors
N_ACC_SENSORS for vibration acceleration sensors

Variables

Variable Name	Req.[math]\displaystyle{ ^a }[/math]	Standard Name	Units of measurement	Dimensions
TIME	R	time	CF-Convention[math]\displaystyle{ ^b }[/math]	TIME
SHEAR	R	[sea][math]\displaystyle{ ^c }[/math]_water_velocity_shear	s-1	TIME, N_SHEAR_SENSORS
PSPD_REL	R	platform_speed_wrt_[sea][math]\displaystyle{ ^c }[/math]_water	m s-1	TIME
SECTION_NUMBER	R	unique_identifier_for_each_section_ of_data_from_timeseries	-	TIME
VIB	HR	platform_vibration	m s-2, or -[math]\displaystyle{ ^d }[/math]	TIME, N_VIB_SENSORS
ACC	O	platform_acceleration	m s-2, or -[math]\displaystyle{ ^d }[/math]	TIME , N_ACC_SENSORS

[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
[math]\displaystyle{ ^d }[/math]: Acceleration and vibration sensors are sometimes not calibrated and their records are used as raw values.

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