Title: Explosive Ice Multiplication Induced by Multiplicative-Noise Fluctuation of Mechanical Breakup in Ice–Ice Collisions

Abstract

The number of ice fragments generated by breakup of large graupel in collisions with small graupel fluctuates randomly owing to fluctuations in relative sizes and densities of colliding graupel particles and the stochastic nature of fracture propagation. This paper investigates the impact of the stochasticity of breakup on ice multiplication. When both the rate of generation of primary ice and the initial number concentration of ice crystals are low, the system most likely loses all the initial ice and graupel owing to a lack of sustaining sources. Even randomness does not change this mean evolution of the system in its phase space. However, a fluctuation of ice breakup number gives a small but finite chance that substantial ice crystal fragments are generated by breakup of large graupel. That, in turn, generates more large graupel. This multiplicative process due to fluctuations potentially leads to a small but finite chance of explosive growth of ice number.A rigorous stochastic analysis demonstrates this point quantitatively. The randomness considered here belongs to a particular category called ‘‘multiplicative’’ noise, because the noise amplitude is proportional to a given physical state. To contrast the multiplicative-noise nature of ice breakup with a standard ‘‘additive’’ noise process, fluctuation ofmore » the primary ice generation rate is also considered as an example of the latter. These processes are examined by taking the Fokker–Planck equation that explicitly describes the evolution of the probability distribution with time. As an important conclusion, stability in the phase space of the cloud microphysical system of breakup in ice–ice collisions is substantially altered by the multiplicative noise.« less

Authors:

Yano, Jun-Ichi ^[1]; Phillips, Vaughan T. J. ^[2]

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+ Show Author Affiliations

1. Météo-France, and CNRS, Toulouse (France). CNRM
2. Univ. of Lund, Lund (Sweden). Dept. of Physical Geography and Ecosystem Science

Publication Date:

Thu Nov 10 00:00:00 EST 2016

Research Org.:

Hebrew Univ. of Jerusalem, Jerusalem (Israel)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1536986

Grant/Contract Number:  

SC0006788

Resource Type:

Accepted Manuscript

Journal Name:

Journal of the Atmospheric Sciences

Additional Journal Information:

Journal Volume: 73; Journal Issue: 12; Journal ID: ISSN 0022-4928

Publisher:

American Meteorological Society

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; meteorology & atmospheric sciences; cloud microphysics