Aerosols and Clouds calibration

Aerosol and cloud calibration is based on the processing of FRAM and LIDAR observations and is performed through a sequence of processing steps. The first step is the determination of whether the observing night satisfies the criteria for a clear night.

Clear night

Clear-night calibration determines whether the atmospheric conditions throughout an observing night are consistent with the reference clear atmosphere. Using FRAM monitoring data, CalibPipe converts the measured aerosol optical depths to Vertical Aerosol Optical Depth (VAOD), evaluates the nightly mean VAOD and its temporal stability, and compares these quantities with configurable site- and season-dependent thresholds. If both criteria are satisfied, the night is classified as clear, the reference clear-night aerosol model is selected for subsequent calibration steps, and no further aerosol calibration is required. Otherwise, the atmospheric calibration workflow proceeds with the analysis of additional atmospheric monitoring data.

Please find below an example configuration.

ClearNightAnalysis:
  stratospheric_aerosols_optical_depth: 0.005
  angstrom_coefficient: 2
  clear_atmosphere_max_vaod: 0.04
  fractional_rms_variability_amplitude_maximum: 0.01
  overwrite: True
  subarray_id: 1