Characterization of Inertia Gravity Waves and Associated Dynamics in the Lower Stratosphere over the Indian Antarctic Station, Bharati (69.4oS, 76.2oE) during Austral Summers.
Abstract
Atmospheric gravity waves over the Polar Regions are found to have numerous effects on the dynamics and chemistry of the middle atmosphere. In the present study, we characterize Inertia Gravity Waves (IGWs) in the lower stratospheric region over the Indian research base in Antarctica, Bharati (69.4oS, 76.2oE) making use of campaign mode radiosonde measurements during the austral summer seasons of 2014-15, 2015-16 and 2016-17. Individual IGW packets identified using wavelet analysis technique 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 summer time lower stratospheric region over Bharati is found to be dominated by IGWs from non-orographic sources. We provide evidences for generation of IGWs from an upper tropospheric jet streak observed over Bharati station. 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. Observations suggest that low potential vorticity intrusion happened as a result of breaking of poleward propagating Rossby wave. 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.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSA23B3125K
- Keywords:
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- 3334 Middle atmosphere dynamics;
- ATMOSPHERIC PROCESSES;
- 3337 Global climate models;
- ATMOSPHERIC PROCESSES;
- 3360 Remote sensing;
- ATMOSPHERIC PROCESSES;
- 3384 Acoustic-gravity waves;
- ATMOSPHERIC PROCESSES