SAFIRE ATR42: PMA/2D-S dataset

The 2D-S cloud microphysics dataset contains microphysics in situ measurements gathered during EUREC4A field campaign with a 2D-Stereo (2D-S) probe installed on the SAFIRE ATR-42 (right-hand underwing pod). The dataset contains one file per flight, 19 files in total.
The 2D-S is an Optical Array Probe that images cloud, drizzle and rain particles in the 10-1280 µm size range (nominal, extended to 2.56 mm in post-processing) onto a linear array of 128 photodiodes with a resolution of 10 µm. The silhouette of each particle crossing the sample area (laser sheet) is reconstructed and recorded as a black and white image by the probe.
The retrieval of particles' geometrical descriptors (size, area, perimeter, ...) from the 2D images is done in post-processing, once most artifacts are corrected (noisy pixel and shattering/splashing event removal, size correction for out-of-focus particles : see process level description field).

The concentrations in the first bins (e.g. up to 30 µm) is a topic of active debate as counts resulting from spurious detection (e.g. noisy pixel) amplified by the shallow depth of field may yield overestimated concentrations.

Available microphysical parameters are Particle Size Distribution (PSD), Total concentration (NT) and Liquid Water Content (LWC, assuming particles are spherical with a density of 1g/cm3 ), given at a frequency of 1 Hz. Data acquisition was synchronized with the ATR-42 GPS synchronized clock and the data is geolocalized using aircraft position.