edu.ucar.opensky::articles:22118 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T15:45:54.848096 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7w3808v Additional global climate cooling by clouds due to ice crystal complexity 2018-11-02T00:00:00Z publication https://n2t.org/ark:/85065/d7w3808v https://doi.org/10.5194/acp-18-15767-2018 Järvinen, Emma author Jourdan, O. author Neubauer, D. author Yao, B. author Liu, C. author Andreae, M. O. author Lohmann, U. author Wendisch, M. author McFarquhar, G. M. author Leisner, T. author Schnaiter, M. author UCAR/NCAR - Library publisher Ice crystal submicron structures have a large impact on the optical properties of cirrus clouds and consequently on their radiative effect. Although there is growing evidence that atmospheric ice crystals are rarely pristine, direct in situ observations of the degree of ice crystal complexity are largely missing. Here we show a comprehensive in situ data set of ice crystal complexity coupled with measurements of the cloud angular scattering functions collected during a number of observational airborne campaigns at diverse geographical locations. Our results demonstrate that an overwhelming fraction (between 61% and 81%) of atmospheric ice crystals sampled in the different regions contain mesoscopic deformations and, as a consequence, a similar flat and featureless angular scattering function is observed. A comparison between the measurements and a database of optical particle properties showed that severely roughened hexagonal aggregates optimally represent the measurements in the observed angular range. Based on this optical model, a new parameterization of the cloud bulk asymmetry factor was introduced and its effects were tested in a global climate model. The modelling results suggest that, due to ice crystal complexity, ice-containing clouds can induce an additional short-wave cooling effect of -1.12 W m(2) on the top-of-the-atmosphere radiative budget that has not yet been considered. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2018 Author(s). This work is licensed under a Creative Commons Attribution 4.0 International license. None eng geoscientificInformation