Lidar data types

Lidar data types in IRIS Focus

Data group

Data moment

In IRIS Focus

Data model

Data level

Scans / tasks

Radial wind data

radial_wind_speed

V - velocity

Time (number of rays or beams) x range (number of bins)

2

All scans

Radial wind data

CNR

SNR - signal-to-noise ratio

Time (number of rays or beams) x range (number of bins)

2

All scans

Radial wind data

CNR

CNR - carrier-to-noise ratio

Time (number of rays or beams) x range (number of bins)

2

All scans

Radial wind data

doppler_spectrum_width

W - spectral width

Time (number of rays or beams) x range (number of bins)

2

All scans

Radial wind data

doppler_spectrum_mean_error

ME - mean error on velocity estimation

Time (number of rays or beams) x range (number of bins)

2

All scans

Radial wind data

radial_wind_speed_ci

CIV - confidence index on velocity

Time (number of rays or beams) x range (number of bins)

2

All scans

Radial wind data

radial_wind_speed_status

STV - quality status on velocity

Time (number of rays or beams) x range (number of bins)

2

All scans

Radial beta data

relative_beta

RELB - relative backscatter

Time (number of rays or beams) x range (number of bins)

3

All scans

Radial absolute beta data

absolute_beta

ABSB - absolute backscatter

Time (number of rays or beams) x range (number of bins)

3

All scans

CNR stands for carrier-to-noise ratio. It represents the number of photons received from aerosol backscatter for a given range gate during the accumulation time. It can also be defined as the ratio between the cumulated power spectral density below the Doppler peak, P(S) (in orange in the graph below) and the cumulated power spectral density corresponding to the noise, P(N) (in blue). In IRIS Focus, CNR is directly obtained from the NetCDF files of the Windcube Scan Lidar.

SNR stands for the signal-to-noise ratio. It is a measure of post-processing signal quality and the quality of the wind velocity estimation.