Consistency test of precipitating ice cloud retrieval properties obtained from the observations of different instruments operating at Dome C (Antarctica)

Abstract

Abstract. Selected case studies of precipitating ice clouds at Dome C (Antarctic Plateau) were used to test a new approach for the estimation of ice cloud reflectivity at 24 GHz (12.37 mm wavelength) using ground-based far infrared spectral measurements from the REFIR-PAD Fourier transform spectroradiometer and backscattering/depolarization lidar profiles. The resulting reflectivity was evaluated with the direct reflectivity measurements provided by a co-located micro rain radar (MRR) operating at 24 GHz, that was able to detect falling crystals with large particle size, typically above 600 µm. To obtain the 24 GHz reflectivity, we used the particle effective diameter and the cloud optical depth retrieved from the far infrared spectral radiances provided by REFIR-PAD and the tropospheric co-located backscattering lidar to calculate the modal radius and the intercept of the particle size distribution. These parameters spanned in the wide ranges between 570–2400 µm and 10−2–104 cm−5, respectively. The retrieved effective sizes and optical depths mostly varied in the ranges 70–250 µm and 0.1–5, respectively. From these parameters, the theoretical reflectivity at 24 GHz was obtained by integrating the size distribution over different cross sections for various habit crystals provided by Eriksson et al. (2018) databases. From the comparison with the radar reflectivity measurements, we found that the hexagonal column-like habits, the columnar crystal aggregates, and the 5/6 branches bullet rosettes showed the best agreement with the MRR observations. The dispersion coefficient of the crystal particle size distribution was assumed in the range 0–2 according to the temperature dependence found in previous studies. The retrieved values of the intercept and slope were found in good agreement with these studies. The presence of the inferred habits was confirmed by the crystal images taken by the ICE-CAMERA, operating in proximity of REFIR-PAD and the MRR. In particular, the occurrence of hexagonal column-like ice crystals was confirmed by the presence of 22∘ solar halos, detected by the HALO-CAMERA. The average crystal lengths obtained from the retrieved size distribution were also compared to those estimated from the ICE-CAMERA images. The agreement between the two results confirmed that the retrieved parameters of the particle size distributions correctly reproduced the observations.

Light scattering matrix for bullet-rosette aggregates of atmospheric ice particles within the geometrical optics approximation

“…According to data of experimental measurements, atmospheric ice aggregates take a significant part of particles in cirrus clouds [29][30][31] , see Fig. 1.…”

Radar‐Derived Snowfall Microphysical Properties at Davis, Antarctica

“…K‐Band Micro Rain Radars (MRRs) have been the central instrument used to monitor and understand the microphysics of snowfall above the surface across the Antarctic in recent years. MRRs have been deployed at Princess Elisabeth Station (72°S,23°E) (Gorodetskaya et al., 2015; Souverijns et al., 2017), Dumont d’Urville (66°S,140°E) (Grazioli, Genthon, et al., 2017; Vignon et al., 2020), Mario Zucchelli (74°S,164°E) (Bracci et al., 2022a; Scarchilli et al., 2020) and Concordia (75°S,123°E) (Di Natale et al., 2022). Recent campaign deployments of scanning X‐Band radars and vertically pointing W‐Band radars at various locations around and adjacent to coastal East Antarctica provided detailed microphysical information on cloud phase, snowfall, and supercooled drizzle (Gehring et al., 2022; Grazioli, Madeleine, et al., 2017), including for the Atmospheric Radiation Measurement (ARM) Measurements of Aerosols, Radiation and Clouds over the Southern Ocean (MARCUS) campaign (Alexander et al., 2021).…”

Data bank of the optical properties of ice particles of cirrus clouds for interpretation of lidar data of Russian Orbital Station

“…Observation of the state of the atmosphere and the underlying surface of the Earth using active remote sensing instruments (such as lidars and radars) installed on spacecraft [15][16][17][18][19][20] make it possible to quickly and globally study climateforming factors and their relationships within the climate system as a whole [21][22][23][24][25][26][27][28][29] .…”