气候变化领域集成服务门户(CCPortal): Characterization of inertia gravity waves and associated dynamics in the lower stratosphere over the Indian Antarctic station; Bharati (69.4°S; 76.2°E) during austral summers

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DOI	10.1007/s00382-019-04665-9
	Characterization of inertia gravity waves and associated dynamics in the lower stratosphere over the Indian Antarctic station; Bharati (69.4°S; 76.2°E) during austral summers
	Koushik N.; Kumar K.K.; Subrahmanyam K.V.; Ramkumar G.; Girach I.A.; Santosh M.; Nalini K.; Nazeer M.; Shreedevi P.R.
发表日期	2019
ISSN	0930-7575
起始页码	2887
结束页码	2903
卷号	53 期号:2020-05-06
英文摘要	Atmospheric gravity waves over the Polar Regions are found to have myriad effects on the dynamics and chemistry of the middle atmosphere. Data collected from high vertical resolution radiosonde measurements carried out in campaign mode from the Indian research base in Antarctica, Bharati (69.4°S, 76.2°E) during the austral summer seasons of 2014–2015, 2015–2016 and 2016–2017 were used to characterize inertia gravity waves (IGWs). Wavelet analysis technique is employed to identify and isolate individual IGW packets. IGWs in the lower stratosphere region are characterized in terms of their vertical and horizontal wavelengths, intrinsic frequencies, directions of propagation, momentum fluxes, energy densities and ground based phase speeds. The observed gravity waves have short vertical wavelengths (~ 2 km) and low intrinsic frequencies (1f–2f). Zonal and meridional components of momentum fluxes are found to have comparable magnitudes. From the direction of propagation estimates, it is observed that the IGWs have a marginal predisposition towards eastward propagation during austral summers. It is found that the lower stratospheric region over Bharati during summertime is dominated by IGWs from non-orographic sources. Evidences for generation of IGWs from an upper tropospheric jet streak observed over Bharati station are provided. The jet streak is found to be associated with the intrusion of low potential vorticity air from middle latitudes and the accompanied development of an anti-cyclonic circulation. The observations suggest that low potential vorticity intrusion happened as a result of breaking of poleward propagating Rossby wave. Spontaneous adjustment of the unstable jet could be responsible for the IGW generation. The significance of the present results lie in characterizing the summer time IGW over the Bharati station for the first time using wavelet based approach and identifying the possible source mechanism. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Inertia gravity waves; Lower stratosphere; Middle atmosphere dynamics; Wavelet analysis
语种	英语
scopus关键词	anticyclone; atmospheric dynamics; gravity wave; inertia; Rossby wave; seasonal variation; stratosphere; wavelet analysis; Antarctica
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146061
作者单位	Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, 695022, India
推荐引用方式 GB/T 7714	Koushik N.,Kumar K.K.,Subrahmanyam K.V.,et al. Characterization of inertia gravity waves and associated dynamics in the lower stratosphere over the Indian Antarctic station; Bharati (69.4°S; 76.2°E) during austral summers[J],2019,53(2020-05-06).
APA	Koushik N..,Kumar K.K..,Subrahmanyam K.V..,Ramkumar G..,Girach I.A..,...&Shreedevi P.R..(2019).Characterization of inertia gravity waves and associated dynamics in the lower stratosphere over the Indian Antarctic station; Bharati (69.4°S; 76.2°E) during austral summers.Climate Dynamics,53(2020-05-06).
MLA	Koushik N.,et al."Characterization of inertia gravity waves and associated dynamics in the lower stratosphere over the Indian Antarctic station; Bharati (69.4°S; 76.2°E) during austral summers".Climate Dynamics 53.2020-05-06(2019).