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The Role of Ice Splintering on Microphysics of Deep Convective Clouds Forming Under Different Aerosol Conditions: Simulations Using the Model With Spectral Bin Microphysics
Author(s) -
Qu Yi,
Khain Alexander,
Phillips Vaughan,
Ilotoviz Eyal,
Shpund Jacob,
Patade Sachin,
Chen Baojun
Publication year - 2020
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2019jd031312
Subject(s) - ice nucleus , ice crystals , cloud condensation nuclei , clear ice , sea ice growth processes , atmospheric sciences , aerosol , condensation , drop (telecommunication) , bin , nucleation , meteorology , environmental science , sea ice , geology , physics , sea ice thickness , antarctic sea ice , arctic ice pack , thermodynamics , telecommunications , algorithm , computer science
Observations during the Ice in Clouds Experiment‐Tropical (ICE‐T) field experiment show that the ice particles concentration in a developing deep convective clouds at the level of T = −15 °C reached about 500 L −1 , that is, many orders higher than that of ice‐nucleating particle. To simulate microphysics of these clouds, the 2‐D Hebrew University Cloud model (HUCM) with spectral bin microphysics was used in which two main types of ice multiplication mechanisms were included in addition to the Hallet‐Mossop mechanism. In the first ice multiplication mechanism ice splinters form by drop freezing and drop‐ice collisions. Ice multiplication of this type dominates during developing stage of cloud evolution, when liquid water content is significant. At later stage when clouds become nearly glaciated, ice crystals are produced largely by ice splintering during ice‐ice collisions (the second ice multiplication mechanism). Simulations show that droplet size distributions, as well as size distributions of ice particles, agree well with the measurements during ICE‐T. Simulations with different cloud condensation nuclei concentrations show the existence of the “optimum” cloud condensation nuclei concentration (or droplet concentration), at which concentration of ice splinters reaches maximum. In these simulations ice nucleation caused by the direct formation of ice crystals upon ice‐nucleating particles, as well as the Hallett‐Mossop process, has a negligible contribution to the ice crystal concentration.