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 filenameoutput: output filename or directoryoptions: see Options belowalgorithm_options: see Algorithm options below
Types:
blview: Vaisala BL-VIEW L2 productchm15k: Lufft CHM 15kcl31: Vaisala CL31cl51: Vaisala CL51cl61: Vaisala CL61cosp: COSP simulated lidardefault: the same format as the output ofalcf lidarminimpl: Sigma Space MiniMPLmpl: 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 or0if 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 thefix_cl_rangeoption (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.fix_cl_range(experimental): Fix CL31/CL51 range correction (ifnoise_h2firmware option if off). The critical range is taken fromcl_crit_range.lat: <lat>: Latitude of the instrument (degrees North). Default: Taken from lidar data ornoneif not available.lon: <lon>: Longitude of the instrument (degrees East). Default: Taken from lidar data ornoneif not available.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 thresholdcloud_nsd: <n>: Number of noise standard deviations to subtract. Default:5.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 algorithmnone: disable cloud base detection
- Calibration:
default: multiply backscatter by a calibration coefficientcalibration_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
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.
Examples:
Process Vaisala CL51 data in cl51_nc and store the output in
cl51_alcf_lidar, assuming instrument altitude of 100 m above sea level.
alcf lidar cl51 cl51_nc cl51_alcf_lidar altitude: 100

ALCF