TY  - JOUR
AU  - Järvinen, Emma
AU  - Schnaiter, Martin
AU  - Mioche, Guillaume
AU  - Jourdan, Olivier
AU  - Shcherbakov, Valery N.
AU  - Costa, Anja
AU  - Afchine, Armin
AU  - Krämer, Martina
AU  - Heidelberg, Fabian
AU  - Jurkat, Tina
AU  - Voigt, Christiane
AU  - Schlager, Hans
AU  - Nichman, Leonid
AU  - Gallagher, Martin
AU  - Hirst, Edwin
AU  - Schmitt, Carl
AU  - Bansemer, Aaron
AU  - Heymsfield, Andy
AU  - Lawson, Paul
AU  - Tricoli, Ugo
AU  - Pfeilsticker, Klaus
AU  - Vochezer, Paul
AU  - Möhler, Ottmar
AU  - Leisner, Thomas
TI  - Quasi-Spherical Ice in Convective Clouds
JO  - Journal of the atmospheric sciences
VL  - 73
IS  - 10
SN  - 1520-0469
CY  - Boston, Mass.
PB  - American Meteorological Soc.
M1  - FZJ-2016-05939
SP  - 3885 - 3910
PY  - 2016
AB  - Homogeneous freezing of supercooled droplets occurs in convective systems in low and midlatitudes. This droplet-freezing process leads to the formation of a large amount of small ice particles, so-called frozen droplets, that are transported to the upper parts of anvil outflows, where they can influence the cloud radiative properties. However, the detailed microphysics and, thus, the scattering properties of these small ice particles are highly uncertain. Here, the link between the microphysical and optical properties of frozen droplets is investigated in cloud chamber experiments, where the frozen droplets were formed, grown, and sublimated under controlled conditions. It was found that frozen droplets developed a high degree of small-scale complexity after their initial formation and subsequent growth. During sublimation, the small-scale complexity disappeared, releasing a smooth and near-spherical ice particle. Angular light scattering and depolarization measurements confirmed that these sublimating frozen droplets scattered light similar to spherical particles: that is, they had angular light-scattering properties similar to water droplets. The knowledge gained from this laboratory study was applied to two case studies of aircraft measurements in midlatitude and tropical convective systems. The in situ aircraft measurements confirmed that the microphysics of frozen droplets is dependent on the humidity conditions they are exposed to (growth or sublimation). The existence of optically spherical frozen droplets can be important for the radiative properties of detraining convective outflows.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000384679900007
DO  - DOI:10.1175/JAS-D-15-0365.1
UR  - https://juser.fz-juelich.de/record/820670
ER  -