气候变化领域集成服务门户(CCPortal): Time-Lapse Acoustic Imaging of Mesoscale and Fine-Scale Variability within the Faroe-Shetland Channel

CCPortal

DOI	10.1029/2019JC015861
	Time-Lapse Acoustic Imaging of Mesoscale and Fine-Scale Variability within the Faroe-Shetland Channel
	Dickinson A.; White N.J.; Caulfield C.P.
发表日期	2020
ISSN	21699275
卷号	125 期号:8
英文摘要	We describe and analyze the results of a three-dimensional seismic (i.e., acoustic) reflection survey from the Faroe-Shetland Channel that is calibrated with near-coincident hydrographic and satellite observations. 54 vertical seismic transects were acquired over a period of 25 days. On each transect, a 250- to 400-m-thick band of reflections is observed within the water column. Hydrographic measurements demonstrate that this reflective band is caused by temperature variations within the pycnocline that separates warm, near-surface waters of Atlantic origin from cold, deep waters that flow southward from the Nordic Seas. Tilting of reflective surfaces records geostrophic shear between these near-surface and deep waters. Measurements of temporal changes of pycnoclinic depth and of reflection tilt are used to infer the existence of an anticyclonic vortex that advects northeastward. Comparison with satellite measurements of sea-surface temperature and height suggests that this vortex is caused by meandering of the Continental Slope Current. A model of a Gaussian vortex is used to match seismic and satellite observations. This putative vortex grows to have a core radius of 40–50 km. It has a maximum azimuthal velocity of 0.3–0.4 m s−1 and translates at 0.01–0.1 m s−1. Within the pycnocline, diapycnal diffusivity, K, is estimated by analyzing the turbulent spectral subrange of tracked reflections. K varies between 10−5.7 m2 s−1and 10−5.0 m2 s−1 in a pattern that is broadly consistent with translation of the vortex. Our integrated study demonstrates the ability of time-lapse seismic reflection surveys to dynamically resolve the effects that mesoscale activity has upon deep thermohaline structure on scales from meters to hundreds of kilometers. ©2020. American Geophysical Union. All Rights Reserved.
语种	英语
来源期刊	Journal of Geophysical Research: Oceans
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/186709
作者单位	Bullard Laboratories, Department of Earth Sciences, University of Cambridge, Cambridge, United Kingdom; Now at Department of Physics, University of York, York, United Kingdom; BP Institute, University of Cambridge, Cambridge, United Kingdom; Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom
推荐引用方式 GB/T 7714	Dickinson A.,White N.J.,Caulfield C.P.. Time-Lapse Acoustic Imaging of Mesoscale and Fine-Scale Variability within the Faroe-Shetland Channel[J],2020,125(8).
APA	Dickinson A.,White N.J.,&Caulfield C.P..(2020).Time-Lapse Acoustic Imaging of Mesoscale and Fine-Scale Variability within the Faroe-Shetland Channel.Journal of Geophysical Research: Oceans,125(8).
MLA	Dickinson A.,et al."Time-Lapse Acoustic Imaging of Mesoscale and Fine-Scale Variability within the Faroe-Shetland Channel".Journal of Geophysical Research: Oceans 125.8(2020).