气候变化领域集成服务门户(CCPortal): Generation and Intensification of Mesoscale Anticyclones by Orographic Wind Jets: The Case of Ierapetra Eddies Forced by the Etesians

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DOI	10.1029/2019JC015810
	Generation and Intensification of Mesoscale Anticyclones by Orographic Wind Jets: The Case of Ierapetra Eddies Forced by the Etesians
	Ioannou A.; Stegner A.; Dubos T.; Le Vu B.; Speich S.
发表日期	2020
ISSN	21699275
卷号	125 期号:8
英文摘要	Motivated by the recurrent formation and intensification of the Ierapetra anticyclones in the southeast of Crete, we investigated with a reduced gravity model the response of the oceanic surface layer to a seasonal wind jet that varies slowly (over several weeks or months) and mimics the Etesian winds. Our study answers why the oceanic response to such forcing is mainly a large and intense anticyclone. We build a dimensionless parameter that integrates in time the Ekman pumping and quantifies the relative amplitude of the isopycnal displacement induced by the local wind stress curl. According to the range of the wind forcing parameter, the oceanic response to a symmetric wind jet could be a symmetric dipole or a strongly asymmetric structure dominated by an intense and robust anticyclone. This intrinsic asymmetry is driven by the finite isopycnal displacements that occur when the wind forcing parameter reaches unity. Since the anticyclonic wind shear for the Etesian wind jet is 2 times larger than the cyclonic one, the asymmetry of the oceanic response is enhanced. Several weeks after the wind forcing has stopped, an intense mesoscale anticyclone which satisfies the cyclogeostrophic balance remains. Moreover, if a similar wind jet blows on a preexisting anticyclone, the latter remains robust and coherent and gets reintensified in agreement with the previous analysis of remote sensing observations. Hence, this paper is the first numerical study which provides a dynamical understanding for the formation of the single Ierapetra anticyclones and explains their intensification 1 year after formation. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	eddy generation; eddy intensification; Etesian wind forcing; orographic wind jets; regional wind stress curl; wind-forced mesoscale eddies
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/186737
作者单位	Laboratoire de Météorologie Dynamique, CNRS, Ecole Polytechnique, Palaiseau, France; Laboratoire de Météorologie Dynamique, CNRS, Ecole Normale Supérieure, Paris, France
推荐引用方式 GB/T 7714	Ioannou A.,Stegner A.,Dubos T.,et al. Generation and Intensification of Mesoscale Anticyclones by Orographic Wind Jets: The Case of Ierapetra Eddies Forced by the Etesians[J],2020,125(8).
APA	Ioannou A.,Stegner A.,Dubos T.,Le Vu B.,&Speich S..(2020).Generation and Intensification of Mesoscale Anticyclones by Orographic Wind Jets: The Case of Ierapetra Eddies Forced by the Etesians.Journal of Geophysical Research: Oceans,125(8).
MLA	Ioannou A.,et al."Generation and Intensification of Mesoscale Anticyclones by Orographic Wind Jets: The Case of Ierapetra Eddies Forced by the Etesians".Journal of Geophysical Research: Oceans 125.8(2020).