Coupling of the microphysical and optical properties of an Arctic nimbostratus cloud during the ASTAR 2004 experiment: Implications for light-scattering modeling

• Published in: Journal of Geophysical Research
• Main Authors: Jourdan, Olivier, Mioche, Guillaume, Garrett, Timothy, Schwarzenboeck, Alfons, Vidot, Jérôme, Xie, Yu, Shcherbakov, Valery, Yang, Ping, Gayet, Jean-François
• Other Authors: Laboratoire de météorologie physique (LaMP), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), IUT d'Allier (IUT d'Allier), Université Clermont Auvergne 2017-2020 (UCA 2017-2020 ), Binghamton University SUNY, State University of New York (SUNY)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Arctic; Alfred Wegener Institute; Spitsbergen
• Online Access: https://hal.science/hal-01893505; https://hal.science/hal-01893505/document; https://hal.science/hal-01893505/file/JourdanetalJGR2010JD014016.pdf; https://doi.org/10.1029/2010jd014016

International audience [1] Airborne measurements in an Arctic mixed-phase nimbostratus cloud were conducted in Spitsbergen on 21 May 2004 during the international Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR) campaign. The in situ instrument suite aboard the Alfred Wegener Institute Polar 2 aircraft included a polar nephelometer (PN), a cloud particle imager (CPI), a Nevzorov probe, and a standard PMS 2DC probe to measure the cloud particle single-scattering properties (at a wavelength of 0.8 mm), and the particle morphology and size, as well as the in-cloud partitioning of ice/water content. The main objective of this work is to present a technique based on principal component analysis and light-scattering modeling to link the microphysical properties of cloud particles to their optical characteristics. The technique is applied to the data collected during the 21 May case study where a wide variety of ice crystal shapes and liquid water fractions were observed at temperatures ranging from −1°C to −12°C. CPI measurements highlight the presence of large supercooled water droplets with diameters close to 500 mm. Although the majority of ice particles were found to have irregular shapes, columns and needles were the prevailing regular habits between −3°C and −6°C while stellars and plates were observed at temperatures below −8°C. The implementation of the principal component analysis of the PN scattering phase function measurements revealed representative optical patterns that were consistent with the particle habit classification derived from the CPI. This indicates that the synergy between the CPI and the PN can be exploited to link the microphysical and shape properties of cloud particles to their single-scattering characteristics. Using light-scattering modeling, we have established equivalent microphysical models based on a limited set of free parameters (roughness, mixture of idealized particle habits, and aspect ratio of ice crystals) that reproduce the main optical features assessed ...