Author :
G. Venkata Chalapathi, S. Eswaraiah, M. Venkat Ratnam, K. Niranjan Kumar, P. Vishnu Prasanth, Jaewook Lee, Yong Ha Kim, S.V.B. Rao
Volume :
10
Issue :
1
Abstract :
Objective: It is theoretically observed that atmospheric gravity waves play a key role in vertical coupling during the Mesosphere
Temperature Inversion (MTI). Therefore, the present paper describes the observational evidence for vertical coupling between
the stratosphere and mesosphere through the short-period gravity waves (GWs), during the Mesosphere Temperature Inversion
(MTI) over a tropical region, Gadanki (13.5o
N, 79.2o
E), India.
Method: The combined observations of Mesosphere-Stratosphere-Troposphere (MST) Radar and Rayleigh LIDAR located at
Gadanki is utilized to study the vertical coupling. We used a unique experimental design from the two ground-based instruments
that scan the lower and middle atmosphere simultaneously during the observational campaign. This kind of combined instruments
are very sparsely located on the same site to make the observations unique to understand the vertical coupling processes
of GWs.
Result: The vertical flux of the horizontal momentum of GWs of periods in the range 20 min. to 2h is investigated in the mesosphere
using the MST Radar winds. The emphasis is made on the variability of zonal and meridional momentum fluxes in the
mesosphere and possible reasons for the variability of fluxes during MTI. It is observed that raise in momentum fluxes of ~7 m2
/
s2
in the eastward flux and ~10 m2
/s2
in southward flux at mesospheric altitudes during the MTI.
Conclusion: The gravity wave (GW) analysis using the LIDAR temperature profiles indicate the connection between GW breaking
at mesosphere altitudes and temperature inversion and thus the turbulence caused mesospheric echoes. The study suggests
the prospect of coupling between stratosphere and mesosphere during the MTI.
Keyword :
Gravity wave coupling, Mesospheric Temperature Inversion (MTI), MST Radar, Rayleigh LIDAR