ALCF^beta

Command line interface

alcf lidar

alcf lidar - process lidar data

The processing is done in the following order:

• noise removal
• calibration
• time resampling
• height resampling
• cloud detection
• cloud base detection

Usage: alcf lidar <type> <lidar> <output> [<options>] [<algorithm_options>]

Arguments:

• type: lidar type (see Types below)
• lidar: input lidar data directory or filename
• output: output filename or directory
• options: see Options below
• algorithm_options: see Algorithm options below

Types:

• chm15k: Lufft CHM 15k
• cl31: Vaisala CL31
• cl51: Vaisala CL51
• cosp: COSP simulated lidar
• minimpl: Sigma Space MiniMPL
• mpl: Sigma Space MPL (converted via SigmaMPL)
• mpl2nc: Sigma Space MPL (converted via mpl2nc)

Options:

• altitude: Altitude of the instrument (m). Default: Taken from lidar data or 0 if not available.
• calibration: <algorithm>: Backscatter calibration algorithm. Available algorithms: default, none. Default: default.
• couple: <directory>: Couple to other lidar data. Default: none.
• cl_crit_range: <range>: Critical range for the fix_cl_range option (m). Default: 6000.
• cloud_detection: <algorithm>: Cloud detection algorithm. Available algorithms: default, none. Default: default.
• cloud_base_detection: <algorithm>: Cloud base detection algorithm. Available algorithms: default, none. Default: default.
• eta: <eta>: Multiple-scattering factor to assume in lidar ratio calculation. Default: 0.7.
• fix_cl_range (experimental): Fix CL31/CL51 range correction (if noise_h2 firmware option if off). The critical range is taken from cl_crit_range.
• noise_removal: <algorithm>: Noise removal algorithm. Available algorithms: default, none. Default: default.
• output_sampling: <period>: Output sampling period (seconds). Default: 86400 (24 hours).
• tlim: { <low> <high> }: Time limits (see Time format below). Default: none.
• tres: <tres>: Time resolution (seconds). Default: 300 (5 min).
• tshift: <tshift>: Time shift (seconds). Default: 0.
• zlim: { <low> <high> }: Height limits (m). Default: { 0 15000 }.
• zres: <zres>: Height resolution (m). Default: 50.

Algorithm options:

• Cloud detection:
  • default: cloud detection based on backscatter threshold
    • cloud_nsd: <n>: Number of noise standard deviations to subtract. Default: 3.
    • cloud_threshold: <threshold>: Cloud detection threshold (sr^-1.m^-1). Default: 2e-6.
  • none: disable cloud detection
• Cloud base detection:
  • default: cloud base detection based cloud mask produced by the cloud detection algorithm
  • none: disable cloud base detection
• Calibration:
  • default: multiply backscatter by a calibration coefficient
    • calibration_file: <file>: calibration file
  • none: disable calibration
• Noise removal:
  • default:
    • noise_removal_sampling: <period>: Sampling period for noise removal (seconds). Default: 300.
  • none: disable noise removal