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The Wegener-Bergeron-Findeisen process – Its discovery and vital importance for weather and climate

Storelvmo, Trude; Tan, Ivy

Meteorologische Zeitschrift Vol. 24 No. 4 (2015), p. 455 - 461

37 references

published: Jul 21, 2015
published online: Apr 13, 2015
manuscript accepted: Oct 20, 2014
manuscript revision received: Oct 16, 2014
manuscript revision requested: Oct 3, 2014
manuscript received: Jul 11, 2014

DOI: 10.1127/metz/2015/0626

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Abstract

The Wegener-Bergeron-Findeisen process refers to the rapid growth of ice crystals at the expense of surrounding cloud droplets, which frequently occurs in atmospheric mixed-phase clouds. The process is a result of the difference in saturation vapor pressures with respect to liquid and ice, and may in some circumstances lead to abrupt and complete cloud glaciation at temperatures between −40 °C and 0 °C in the Earth's atmosphere. The process is named after three eminent scientists who were active in the first half of the 20th century, among them being German meteorologist Walter Findeisen (1909–1945). In his classical paper published in 1938, Findeisen described the contemporary understanding of the Wegener-Bergeron-Findeisen process and other key cloud microphysical processes. Here, we compare the understanding of the aforementioned processes at the time with that of the present, and find that they are remarkably similar. We also discuss how the Wegener-Bergeron-Findeisen process is implemented in state-of-the-art numerical models of the atmosphere, and highlight its importance for both weather and climate.

Keywords

Wegener-Bergeron-Findeisen processmixed-phase cloudsweather and climate