气候变化领域集成服务门户(CCPortal): Local and Remote Controls on Arctic Mixed-Layer Evolution

CCPortal

DOI	10.1029/2019MS001671
	Local and Remote Controls on Arctic Mixed-Layer Evolution
	Neggers R.A.J.; Chylik J.; Egerer U.; Griesche H.; Schemann V.; Seifert P.; Siebert H.; Macke A.
发表日期	2019
ISSN	19422466
起始页码	2214
结束页码	2237
卷号	11 期号:7
英文摘要	In this study Lagrangian large-eddy simulation of cloudy mixed layers in evolving warm air masses in the Arctic is constrained by in situ observations from the recent PASCAL field campaign. A key novelty is that time dependence is maintained in the large-scale forcings. An iterative procedure featuring large-eddy simulation on microgrids is explored to calibrate the case setup, inspired by and making use of the typically long memory of Arctic air masses for upstream conditions. The simulated mixed-phase clouds are part of a turbulent mixed layer that is weakly coupled to the surface and is occasionally capped by a shallow humidity layer. All eight simulated mixed layers exhibit a strong time evolution across a range of time scales, including diurnal but also synoptic fingerprints. A few cases experience rapid cloud collapse, coinciding with a rapid decrease in mixed-layer depth. To gain insight, composite budget analyses are performed. In the mixed-layer interior the heat and moisture budgets are dominated by turbulent transport, radiative cooling, and precipitation. However, near the thermal inversion the large-scale vertical advection also contributes significantly, showing a distinct difference between subsidence and upsidence conditions. A bulk mass budget analysis reveals that entrainment deepening behaves almost time-constantly, as long as clouds are present. In contrast, large-scale subsidence fluctuates much more strongly and can both counteract and boost boundary-layer deepening resulting from entrainment. Strong and sudden subsidence events following prolonged deepening periods are found to cause the cloud collapses, associated with a substantial reduction in the surface downward longwave radiative flux. ©2019. The Authors.
英文关键词	Arctic mixed layers; Arctic mixed-phase clouds; large-eddy simulation; large-scale subsidence; Polarstern research Vessel; warm air intrusions
语种	英语
scopus关键词	Atmospheric thermodynamics; Boundary layers; Budget control; Radiative Cooling; Remote control; Ships; Subsidence; In-situ observations; Mixed layer; Mixed-phase cloud; Research vessels; Substantial reduction; Turbulent transports; Upstream conditions; Warm air; Large eddy simulation; advection; air mass; atmospheric forcing; atmospheric transport; calibration; cloud; cooling; field method; in situ measurement; Lagrangian analysis; large eddy simulation; mixed layer; moisture content; precipitation (climatology); research vessel; turbulent mixing; warm water
来源期刊	Journal of Advances in Modeling Earth Systems
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/156965
作者单位	Institute for Geophysics and Meteorology, University of Cologne, Cologne, Germany; Leibniz Institute for Tropospheric Research (TROPOS), Leipzig, Germany
推荐引用方式 GB/T 7714	Neggers R.A.J.,Chylik J.,Egerer U.,et al. Local and Remote Controls on Arctic Mixed-Layer Evolution[J],2019,11(7).
APA	Neggers R.A.J..,Chylik J..,Egerer U..,Griesche H..,Schemann V..,...&Macke A..(2019).Local and Remote Controls on Arctic Mixed-Layer Evolution.Journal of Advances in Modeling Earth Systems,11(7).
MLA	Neggers R.A.J.,et al."Local and Remote Controls on Arctic Mixed-Layer Evolution".Journal of Advances in Modeling Earth Systems 11.7(2019).