On the Estimation of Lagrangian Diffusivity: Influence of Nonstationary Mean Flow

CORC > 南海海洋研究所 > 中国科学院南海海洋研究所 > 热带海洋环境国家重点实验室(LTO)

	On the Estimation of Lagrangian Diffusivity: Influence of Nonstationary Mean Flow
	Qian, YK ; Peng, SQ ; Liang, CX ; Lumpkin, R
刊名	JOURNAL OF PHYSICAL OCEANOGRAPHY
	2014
卷号	44 期号:10 页码:2796-2811
ISSN号	0022-3670
通讯作者	speng@scsio.ac.cn
中文摘要	Eddy mean flow decomposition is crucial to the estimation of Lagrangian diffusivity based on drifter data. Previous studies have shown that inhomogeneous mean flow induces shear dispersion that increases the estimated diffusivity with time. In the present study, the influences of nonstationary mean flows on the estimation of Lagrangian diffusivity, especially the asymptotic behavior, are investigated using a first-order stochastic model, with both idealized and satellite-based oceanic mean flows. Results from both experiments show that, in addition to inhomogeneity, nonstationarity of mean flows that contain slowly varying signals, such as a seasonal cycle, also cause large biases in the estimates of diffusivity within a time lag of 2 months if a traditional binning method is used. Therefore, when assessing Lagrangian diffusivity over regions where a seasonal cycle is significant [e.g., the Indian Ocean (IO) dominated by monsoon winds], inhomogeneity and nonstationarity of the mean flow should be simultaneously taken into account in eddy mean flow decomposition. A temporally and spatially continuous fit through the Gauss Markov (GM) estimator turns out to be very efficient in isolating the effects of inhomogeneity and nonstationarity of the mean flow, resulting in estimates that are closest to the true diffusivity, especially in regions where strong seasonal cycles exist such as the eastern coast of Somalia and the equatorial IO.
学科主题	Oceanography
收录类别	SCI
资助信息	Strategic Priority Research Program of the Chinese Academy of Sciences [XDA11010304]; MOST of China [2011CB403505, 2010CB950302]; Knowledge Innovation Program of the Chinese Academy of Sciences [SQ201305]; National Natural Science Foundation of China [41376021, 41306013]; Hundred Talent Program of the Chinese Academy of Sciences; NOAA's Climate Program Office; Atlantic Oceanographic and Meteorological Laboratory
原文出处	AMER METEOROLOGICAL SOC
WOS记录号	WOS:000342861100012
公开日期	2014-12-11
内容类型	期刊论文
源URL	[http://ir.scsio.ac.cn/handle/344004/10503]
专题	南海海洋研究所_热带海洋环境国家重点实验室(LTO)
推荐引用方式 GB/T 7714	Qian, YK,Peng, SQ,Liang, CX,et al. On the Estimation of Lagrangian Diffusivity: Influence of Nonstationary Mean Flow[J]. JOURNAL OF PHYSICAL OCEANOGRAPHY,2014,44(10):2796-2811.
APA	Qian, YK,Peng, SQ,Liang, CX,&Lumpkin, R.(2014).On the Estimation of Lagrangian Diffusivity: Influence of Nonstationary Mean Flow.JOURNAL OF PHYSICAL OCEANOGRAPHY,44(10),2796-2811.
MLA	Qian, YK,et al."On the Estimation of Lagrangian Diffusivity: Influence of Nonstationary Mean Flow".JOURNAL OF PHYSICAL OCEANOGRAPHY 44.10(2014):2796-2811.