일몰 후 지표 부근 혼합층 발달 사례 분석

Abstract

Atmospheric boundary layer was intensively observed in three islands of the west sea from 18:00 on March 9, 2016 to March 12, 06:00 2016. In the atmospheric boundary layer observed at night, a mixed layer was developed instead of a stable layer. In this study, we investigated the cause of restriction of the stable layer and development of the mixed layer at night. The observed nocturnal potential temperature profiles in Daebudo showed the mixed layers on March 9 and March 10, and the stable layers on March 11. In order to understand the development of the mixed layer and the stable layer, the production ratios, which are buoyancy production term and shear production term in the turbulent kinetic energy equation were analyzed. Buoyant heat fluxes gradually increased during nighttime on March 9 and peaked at midnight, and gradually decreased thereafter. On March 9, nocturnal mixed layer was developed by buoyancy heat flux. On the other hand, we could not explain the mixed layer development with the buoyant heat flux on March 10. The shear production terms on March 10 night were higher than on March 9 and March 11. Especially, at 21:00 on March 10, when the mixed layer height was the highest during the intensive observation period(IOP), the shear production was maximum. On March 11, the buoyancy and the shear production at night were the lowest during IOP, so stable layer was formed. The increase of buoyancy and shear production played important role in the mixed layer at night.