The calculation of the number of ice crystals for the model of frazil ice evolution is very important and affects the whole frazil events. In this paper, the general formula for the number of frazil ice crystals was established considering secondary nucleation, flocculation, gravity and turbulent entrainment, and ice crystals by melting. Meanwhile, two physical processes of secondary nucleation and flocculation were expressed by introducing critical impact velocity and the probability of flocculation from previous models. It has been found that the simulation results of frazil ice evolution are in good agreement with the experimental data and actual project. Then, Sobol method is carried out to judge parameters' influence degree, which found the number of nuclei produced [Formula: see text] is the most sensitive and has the greatest influence on the model results. In addition, sensitivity analysis of these parameters shows that they can affect the maximum supercooling and the period of supercooling. Therefore, the calculation method of the number of ice crystals is applied, which provides technical support for exploring the water temperature and internal relationship of frazil ice evolution.
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http://dx.doi.org/10.1038/s41598-023-33097-z | DOI Listing |
Commun Earth Environ
November 2024
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany.
The ice-covered period of large Arctic rivers is shortening. To what extent will this affect biogeochemical processing of nutrients? Here we reveal, with silicon isotopes (δSi), a key winter pathway for nutrients under river ice. During colder winter phases in the Lena River catchment, conditions are met for frazil ice accumulation, which creates microzones.
View Article and Find Full Text PDFAnn Rev Mar Sci
July 2024
4Ocean Sciences Division, US Naval Research Laboratory, Stennis Space Center, Mississippi, USA.
Sediments covering Arctic continental shelves are uniquely impacted by ice processes. Delivery of sediments is generally limited to the summer, when rivers are ice free, permafrost bluffs are thawing, and sea ice is undergoing its seasonal retreat. Once delivered to the coastal zone, sediments follow complex pathways to their final depocenters-for example, fluvial sediments may experience enhanced seaward advection in the spring due to routing under nearshore sea ice; during the open-water season, boundary-layer transport may be altered by strong stratification in the ocean due to ice melt; during the fall storm season, sediments may be entrained into sea ice through the production of anchor ice and frazil; and in the winter, large ice keels more than 20 m tall plow the seafloor (sometimes to seabed depths of 1-2 m), creating a type of physical mixing that dwarfs the decimeter-scale mixing from bioturbation observed in lower-latitude shelf systems.
View Article and Find Full Text PDFSci Rep
April 2023
State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin, China.
The calculation of the number of ice crystals for the model of frazil ice evolution is very important and affects the whole frazil events. In this paper, the general formula for the number of frazil ice crystals was established considering secondary nucleation, flocculation, gravity and turbulent entrainment, and ice crystals by melting. Meanwhile, two physical processes of secondary nucleation and flocculation were expressed by introducing critical impact velocity and the probability of flocculation from previous models.
View Article and Find Full Text PDFEnviron Sci Technol
February 2023
Department of Building, Civil and Environmental Engineering, Concordia University, Montreal, Quebec H3G 1M8, Canada.
Sea ice can serve as a temporary sink for microplastics (MPs), and thus, it too can function as a secondary source of and transport medium for MPs. This study aimed to explore the effect of various MP properties and environmental characteristics on the entrainment and enrichment of MPs in ice under varying turbulence conditions. It was found that high rotation speed in freshwater distinctively enhanced the entrainment of hydrophobic MPs in ice, this being attributable to the combined effects of frazil ice and air bubbles.
View Article and Find Full Text PDFSci Adv
October 2022
National Institute of Polar Research, Tachikawa 190-8518, Japan.
Antarctic Bottom Water (AABW) occupies the abyssal layer of the world ocean and contributes to the global overturning circulation. It originates from dense shelf water, which forms from brine rejection during sea ice production. An important region of AABW formation has been identified off the Cape Darnley polynya.
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