Inâ€cloud variability of LIDAR depolarization of polar and midlatitude cirrus

• Published in: Geophysical Research Letters
• Main Authors: Del Guasta, Massimo, Vallar, Edgar
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2003
• Subjects: General Earth and Planetary Sciences; Geophysics; Dumont d'Urville; Dumont-d'Urville; Antarc*; Antarctica
• Online Access: https://www.openaccessrepository.it/record/189352; https://doi.org/10.1029/2003gl017163

LIDAR depolarization is commonly used for discriminating liquid and ice particles. Since depolarization depends in a complicated manner on particle shape and size, inâ€cloud variability of depolarization has been used as an indicator of the microphysical homogeneity of cirrus. The comparison between midlatitude (Florence, Italy, 43. 60°N) and polar (Dumont d'Urville, Antarctica, 66. 68°S) cirrus showed a lower mean depolarization and a higher inâ€cloud uniformity of cloud depolarization for polar clouds in the (−80, −50°C) temperature range. A wider inâ€cloud variability of depolarization was observed in polar clouds at higher temperatures (−50, −30°C), reflecting the presence of supercooled liquid layers. The large inâ€cloud variability of depolarization in Florence cirrus could be explained with a microphysics that is dynamically and chemically perturbed as compared with the polar site. Aged jet contrails are, in fact, present in many Florence cirrus records.