Ice Crystal Complexity and Link to the Cirrus Cloud Radiative Effect

Geophysical monograph, pp. 47–85

Abstract

The aim of this chapter is to present emerging information on ice crystal morphology in the nano- and microscale from various sources, and explore its impact on ice crystal's single-scattering properties and ultimately on cirrus cloud radiative effect. Increasing amount of observations in the last decade have shown that cirrus ice crystals invariably contain some degree of facet roughness, hollowness, or other morphological complexities that make the crystal shape deviate from that of a pristine hexagonal shape. These morphological complexities are found to be present in a wide variety of environmental conditions. A set of physical and statistical complexity parameters is used to quantify ice crystal complexity depending on the application. Although laboratory studies have shown that complexity parameters tend to increase with increasing crystal growth rate, observations in natural cirrus indicate that complexity parameters only weakly vary at cirrus temperatures below 230 K. Morphological complexities affect the optical properties of ice crystals. Implementing the optical properties of complex ice crystals in climate models has shown that the radiative effect of crystal complexity is a cooling of 1–2 Wm −2 globally. Due to the prevalence of ice crystal morphological complexities and their influence on cirrus radiative properties, the radiative effect of crystal complexity should be taken into account in future climate models. However, work is still needed to transfer the increasing knowledge of the physical nature of ice crystal complexity into optical particle models and eventually into parameterizations used in models.

Authors 11

1. Emma Järvinen

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany

2. Bastiaan van Diedenhoven

   Columbia University

   Affiliation as printed

   Center for Climate System Research, Columbia University, New York, NY, USA

3. Nathan Magee

   The College of New Jersey

   Affiliation as printed

   Department of Physics, The College of New Jersey, Ewing, NJ, USA

4. Steven P. Neshyba

   University of Puget Sound

   Affiliation as printed

   Department of Chemistry, University of Puget Sound, Tacoma, WA, USA

5. Martin Schnaiter

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany

6. Guanglang Xu

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany

7. Olivier Jourdan

   Centre National de la Recherche Scientifique · Université Clermont Auvergne · Observatoire de Physique du Globe de Clermont-Ferrand · Laboratoire de Météorologie Physique

   Affiliation as printed

   Laboratoire de Météorologie Physique, Université Clermont Auvergne/OPGC/CNRS, Clermont-Ferrand, France

   Laboratoire de Météorologie Physique, Université Clermont Auvergne/OPGC/CNRS, Clermont-Ferrand, France

8. David James Delene

   University of North Dakota

   Affiliation as printed

   Department of Atmospheric Sciences, University of North Dakota, Grand Forks, ND, USA

9. Fritz Waitz

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany

10. Simone Lolli

    National Research Council - Institute of Methodologies for Environmental Analysis · National Research Council · Universitat Politècnica de Catalunya

    Affiliation as printed

    CommSensLab, Department of Signal Theory and Communications, Universitat Politècnica de Catalunya, Barcelona, Spain

    Institute of Methodologies for Environmental Analysis, National Research Council of Italy, Tito, Italy

    CommSensLab, Department of Signal Theory and Communications, Universitat Politècnica de Catalunya, Barcelona, Spain

11. Seiji Kato Aachen Now at SRON Netherlands Institute for Space Research

    Langley Research Center · Space Research Organisation Netherlands

    Affiliation as printed

    NASA Langley Research Center, Hampton, VA, USA

    now at SRON Netherlands Institute for Space Research, Leiden, Netherlands