Automatic Lidar and Ceilometer

Command line interface

alcf-calibrate – Calibrate ALC backscatter.


alcf calibrate <type> [--] <time_periods> <input> <output>


Calibration based the O’Connor et al. (2004) method of lidar ratio (LR) in fully opaque stratocumulus clouds.

Arguments following -- are treated as literal strings. Use this delimiter if the input or output file names might otherwise be interpreted as non-strings, e.g. purely numerical file names.


  • type: Lidar type (see Types below).
  • time_periods: File containing calibration time periods of stratocumulus clouds in the backscatter profiles (see Time periods below).
  • input: Input directory containing NetCDF files (the output of alcf lidar).
  • output: Output calibration file.


  • chm15k: Lufft CHM 15k.
  • cl31: Vaisala CL31.
  • cl51: Vaisala CL51.
  • minimpl: Sigma Space MiniMPL.
  • mpl: Sigma Space MPL.


Time periods file is a text file containting start and end time (see Time format below) of a time period separated by whitespace, one time period per line:

<start> <end>
<start> <end>

where start is the start time and end is the end time.

Time format

YYYY-MM-DD[THH:MM[:SS]], where YYYY is year, MM is month, DD is day, HH is hour, MM is minute, SS is second. Example: 2000-01-01T00:00:00.


Read time periods from time_periods.txt, lidar profiles from the directory lidar and write the calibration coefficient to calibration.txt.

alcf calibrate time_periods.txt lidar calibration.txt