Comparison of mid-latitude single- and mixed-phase cloud optical depth from co-located infrared spectrometer and backscatter lidar measurements

Year: 2021

Authors: Di Natale G., Barucci M., Belotti C., Bianchini G., D’Amato F., Del Bianco S., Gai M., Montori A., Sussmann R., Viciani S., Vogelmann H., Palchetti L.

Autors Affiliation: CNR INO, Natl Inst Opt, Via Madonna Piano 10, Florence, Italy; CNR IFAC, Inst Appl Phys, Via Madonna del Piano 10, Florence, Italy; Karlsruhe Inst Technol, IMK IFU, Garmisch Partenkirchen, Germany

Abstract: The long-wave downwelling spectral radiance measurements performed by means of the Far-Infrared Radiation Mobile Observation System (FIRMOS) spectrometer at the summit of the Zugspitze (German Alps) in the winter 2018/19 allowed the retrieval of the optical and microphysical properties of ice and mixed clouds, showing a good agreement of the statistical relationship between the ice water path and the ice optical depth with the ones from previous works. In this paper the optical depths retrieved from FIRMOS are initially compared with selected cases calculated from backscattering light detection and ranging (lidar) data by using a transmittance method. Then, in order to compare the whole FIRMOS dataset, the power-law relationship between backscattering and extinction is used to apply the Klett method and automatize the routine. Minimizing the root mean square differences, the exponent k of the powerlaw relationship is assessed to be 0.85 with a variability in the range of 0.60–1.10 for ice clouds and 0.50 with a variability within 0.30–0.70 for mixed clouds.


Volume: 14 (10)      Pages from: 6749  to: 6758

KeyWords: cloud optical depth
infrared spectrometer
DOI: 10.5194/amt-14-6749-2021

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