HR: 16:15h
AN: OS54A-02    [Abstracts]
TI: Large Eddy Simulation of Particle Settling in the Ocean Mixed Layer
AU: * Noh, Y
EM: noh@atmos.yonsei.ac.kr
AF: Department of Atmospheric Sciences, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749 Korea, Republic of
AU: Kang, I
EM: kis@atmos.yonsei.ac.kr
AF: Department of Atmospheric Sciences, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749 Korea, Republic of
AU: Herold, M
EM: m.herold@tu-bs.de
AF: Institute of Aerospace Systems, TU Braunschweig, Hermann Blenke 23, Braunshweig, 38108 Germany
AU: Raasch, S
EM: raasch@muk.uni-hannover.de
AF: Insitute of Meteorology and Climatology, University of Hannover, Herrenhaeuser Str 2, Hannover, 30419 Germany
AB: The settling velocity of suspended particles in the ocean mixed layer, which plays an important role in the biogeochemical process in the ocean, was calculated by analyzing the Lagrangian motion of a large number of particles in the three-dimensional turbulent structure of the ocean mixed layer simulated by LES. Two different types of the ocean mixed layer, with and without Langmuir circulation (LC), and two different types of particles with different terminal velocity in the still fluid ws were investigated. In the presence of LC, particles are swept down rapidly following the downward jets of LC, while the uniform downward propagation of particles characterized by diffusion occurs in the absence of it. Settling velocity is smaller than ws in all experiments, but the magnitude of the decrease is larger in the presence of LC, which is consistent with the Stommel's theory on the inhibition of particle settling by a vortex motion. The vertical distribution of particles and the probability distribution of the vertical velocity of particles also show significant effects of LC. Besides, it was found that the effect of turbulent flows on the particle settling becomes stronger for smaller ws.
DE: 4806 Carbon cycling
DE: 4842 Modeling
DE: 4863 Sedimentation
DE: 4568 Turbulence, diffusion, and mixing processes
DE: 4572 Upper ocean processes
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting