24 Aug 2022
24 Aug 2022
Status: this preprint is currently under review for the journal AMT.

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

Gianluca Di Natale1, David D. Turner2, Giovanni Bianchini1, Massimo Del Guasta1, Luca Palchetti1, Alessandro Bracci3,4, Luca Baldini3, Tiziano Maestri4, William Cossich4, Michele Martinazzo4, and Luca Facheris5 Gianluca Di Natale et al.
  • 1National Institute of Optics, CNR-INO, Via Madonna del Piano 10, Sesto Fiorentino, Firenze, Italy
  • 2NOAA/OAR/Global Systems Laboratory, Boulder, Colorado, USA
  • 3Institute of Atmospheric Sciences and Climate, CNR-ISAC, Rome, Italy
  • 4Department of Physics and Astronomy “Augusto Righi”, Alma Mater Studiorum University of Bologna, Bologna, Italy
  • 5Department of Information Engineering, University of Florence, Via di Santa Marta 3, Firenze, Italy

Abstract. Selected case studies of precipitating ice clouds at Dome-C (Antarctic Plateau) are used to test a new approach for the estimation of ice cloud reflectivity at 24 GHz (12.37 mm of wavelength) using ground-based far infrared spectral measurements from the REFIR-PAD Fourier transform spectroradiometer and backscattering/depolarization lidar profiles. The resulting reflectivity is evaluated with the direct reflectivity measurements provided by a co-located micro rain radar (MRR) operating at 24 GHz, which is able to detect falling crystals with large particle size, typically above 500 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. From these, the theoretical reflectivity at 24 GHz is obtained by integrating the size distribution over different microwave 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 column-like habits and the plates/columnar crystal aggregates show the best agreement with the MRR observations. The presence of (hexagonal) columns is confirmed both by the presence of 22° solar halos, detected by the HALO-CAMERA, and by the crystal images taken by the ICE-CAMERA, operating in proximity of REFIR-PAD and the MRR. The average crystal lengths obtained from the retrieved size distribution are also compared to the ones estimated from the ICE-CAMERA images. The agreement between the two results confirms that the retrieved parameters of the particle size distributions correctly reproduce the observations.

Gianluca Di Natale et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2022-215', Bryan A. Baum, 13 Sep 2022
  • RC2: 'Comment on amt-2022-215', Andrew Heymsfield, 14 Sep 2022

Gianluca Di Natale et al.

Gianluca Di Natale et al.


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Short summary
In this paper we describe a new approach to test the consinstency of the precipitating ice cloud optical and microphysical properties in Antarctica, at Dome-C, retrieved from hyperspectral measurements in the far infrared, with the reflectivity detected by a co-located micro rain radar operating at 24 GHz. The retrieved ice crystal sizes were found in accordance with the direct measurements of an optical imager, also installed at Dome-C, which is able to collect the falling ice particles.