Datenpaket: Dataset: PPD-2K Particle shape and particle size distribution from DOME-C, Antarctica

In-situ measurements of small atmospheric ice crystals (< 100 µm) on the Antarctic plateau are rare. Yet, small ice crystals are abundant in a region that often reaches cirrus temperatures even in the warmest season. The Particle Phase Discriminator (PPD-2K) was deployed on DOME-C, Antarctica during austral summer 2023/2024. It was used to characterize the microphysical and optical properties of individual ice fog and diamond dust ice crystals having spherical equivalent diameters between 11 and 150 µm. These properties included particle concentration, size distribution and spatial light scattering patterns in the forward direction that allow the analysis of the particle sphericity (particle phase), shape and crystal complexity.

PPD-2K Size Distribution from 11-21-2023 094440 UTC until 01-07-2024 222452 UTC. PPD flow: 5 lpm Calibration coefficients: a = 2.02, b = 0.522 and c = 0 Note: Empty images and triggers that are triggered on noise are removed. File 'DOME_C_final_level2': Concentration measurements (optical particle counter) Data produced with 10 s averaging 1st Column: datetime in UTC 2nd Column: Ntot, Total concentration in 1/ccm 3rd Column: dNtot, Uncertainty in total concentration in 1/ccm 4th Column: Droplet_fraction 5th Column: Droplet_fraction upper Clopper-Pearson confidence interval 6th Column: Droplet_fraction lower Clopper-Pearson confidence interval 7th Column onwards: dN/dlogDp for spherical equivalent diameter size bins in 1st row last Column: lidar classification (d: diamond dust, i: ice fog, m: mixed fog, l: liquid cloud precipitation) File 'DOME_C_images_final_level2.csv': Diffraction pattern image analysis Columns: Date,UTC time,Seconds of day,Image name,Folder name,Mean intensity,Saturation ratio,Sphere,Fit,Sphere diameter,FFT_0,FFT_1,FFT_2,FFT_3,FFT_4,FFT_5,FFT_6,FFT_7,FFT_8,k-value,Entropy,Contrast,Homogeneity,Correlation,Energy,combined roughness,Shape,Optical diameter,ICCD gain,Trigger gain,Trigger threshold,Trigger intensity,TOF,Norm Variance,Sum Sq Res Mie,CNN_shape The CNN shapes correspond to: 0: Irregular 1: Large (or nearly saturated) 2: Pristine 3: Rough 4: Small Rough 5: Small (often triggered on noise) 6: Spherical 7: Sublimating The shapes correspond to the maximum Fourier coefficient.