气候变化领域集成服务门户(CCPortal): Spatial and temporal variability of the Agulhas Retroflection: Observations from a new objective detection method

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DOI	10.1016/j.rse.2020.112239
	Spatial and temporal variability of the Agulhas Retroflection: Observations from a new objective detection method
	Russo C.S.; Lamont T.; Krug M.
发表日期	2021
ISSN	00344257
卷号	253
英文摘要	This study presents an improved method to identify the Location of the Agulhas Current's Core and Edges (LACCE), throughout the greater Agulhas system. In this study the method is applied to daily altimetric fields of absolute dynamic topography and geostrophic velocities. LACCE compares favourably with previous algorithms used to track the position of the Agulhas Current. The ability of the LACCE to correctly identify the core and edges of the Agulhas Current is also established through comparisons with along-track altimetry datasets and in situ observations of current speed and direction across both the Agulhas Current and the Agulhas Return Current. Our results show that LACCE can successfully be applied to a merged altimetry dataset to monitor changes in the Agulhas Current's position caused by mesoscale processes such as early retroflection events or transient features like Natal Pulses. To demonstrate the use of the LACCE, the Agulhas Current position outputs from the algorithm computed over a 26-year period (1993 to 2018) are then used to describe the spatial and temporal variability of the Retroflection. Our results show that the Agulhas Retroflection generally occurs in the region from 15.01–20.03°E and 40.47–38.44°S. The retroflection exhibits a trimodal distribution, indicating three preferential longitudes (15, 18 and 19.5°E). Despite not being statistically significant, the results suggest some seasonal variation in the modal position of the Retroflection, with it frequenting western longitudes more during the austral summer, in agreement with previous studies. Early retroflections were found to occur more often during the austral spring and summer, with few taking place in winter and almost none in autumn. The observations from this study agree with previous studies that found the triggering mechanism for early retroflections (east of 22.54°E) to be the interaction between large Agulhas Current meanders (Natal Pulses) with northward extensions of Agulhas Return Current meanders. © 2020 Elsevier Inc.
英文关键词	Agulhas Current location; Agulhas Retroflection; Early retroflections; Greater Agulhas Current system; LACCE; Satellite oceanography; Seasonality
语种	英语
scopus关键词	Remote sensing; Soils; Absolute dynamic topography; Detection methods; In-situ observations; Mesoscale process; Seasonal variation; Spatial and temporal variability; Transient features; Triggering mechanism; Topography; detection method; geostrophic flow; in situ measurement; observational method; seasonal variation; spatial variation; spatiotemporal analysis; temporal variation; topography; Agulhas Current; Indian Ocean; Varanidae
来源期刊	Remote Sensing of Environment
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/179005
作者单位	South African Environmental Observation Network (SAEON), Egagasini Node, 5th Floor Foretrust Building, Martin Hammerschlag Way, Cape Town, 8000, South Africa; Oceans and Coasts Research, Department of Environment, Forestry and Fisheries, P O Box 52126, Victoria & Alfred Waterfront, Cape Town, 8002, South Africa; Bayworld Centre for Research and Education, 5 Riesling Road, Constantia, Cape Town, 7806, South Africa; Nansen-Tutu Centre for Marine Environmental Research, Department of Oceanography, University of Cape Town, Rondebosch, 7700, South Africa
推荐引用方式 GB/T 7714	Russo C.S.,Lamont T.,Krug M.. Spatial and temporal variability of the Agulhas Retroflection: Observations from a new objective detection method[J],2021,253.
APA	Russo C.S.,Lamont T.,&Krug M..(2021).Spatial and temporal variability of the Agulhas Retroflection: Observations from a new objective detection method.Remote Sensing of Environment,253.
MLA	Russo C.S.,et al."Spatial and temporal variability of the Agulhas Retroflection: Observations from a new objective detection method".Remote Sensing of Environment 253(2021).