HR: 0800h
AN: SA31A-13    [Abstracts]
TI: Momentum fluxes of gravity waves and their role in Stratospheric Semi annual Oscillation
AU: * Antonita, M
EM: mariaspl@gmail.com
AF: Space Physics Laboratory, Vikram Sarabhai Space Center, Trivandrum, India., 1Space Physics Laboratory, Vikram Sarabhai Space Center, Trivandrum, India., Trivandrum, 695022, India
AU: Ramkumar, G
EM: geetha_ramkumar@vssc.gov.in
AF: Space Physics Laboratory, Vikram Sarabhai Space Center, Trivandrum, India., 1Space Physics Laboratory, Vikram Sarabhai Space Center, Trivandrum, India., Trivandrum, 695022, India
AU: Kishore Kumar, K
EM: kishore_nmrf@yahoo.com
AF: Space Physics Laboratory, Vikram Sarabhai Space Center, Trivandrum, India., 1Space Physics Laboratory, Vikram Sarabhai Space Center, Trivandrum, India., Trivandrum, 695022, India
AU: Nambhoodiri, K
EM: kv_sambhunambhoodiri@vssc.gov.in
AF: Meteorological Facility, Vikram Sarabhai Space Center, Trivandrum, India, Meteorological Facility, Vikram Sarabhai Space Center, Trivandrum, India, Trivandrum, 695022, India
AU: Bhavani Kumar, Y
EM: geetha_ramkumar@vssc.gov.in
AF: National Atmospheric Research Laboratory, Gadanki, India, National Atmospheric Research Laboratory, Gadanki, India, Gadanki, India
AB: Deposition of energy and momentum fluxes carried by the vertically propagating waves alters the mean flow, which are in turn responsible for the maintenance of periodic oscillation. The need of the hour is to quantify the amount of momentum deposition by the various wave motions. Among all other waves in the atmosphere, the contribution of gravity waves in driving the periodic oscillations is very significant. Divergence/convergence of the energy and momentum fluxes carried by the gravity waves accelerate/ decelerate the mean flow which in turn partly responsible for the maintenance of QBO and SAO, which are the characteristic features of the equatorial region. Once the contribution of gravity waves is quantified it will be very helpful to parameterize these waves in the general circulation models, which are otherwise posing a great challenge to the scientific community. The difficulty in parameterizing these waves arises as its source mechanism and propagation characteristics exhibit a wide range of variability in both temporal and spatial scales. As part of middle atmospheric dynamics program (MIDAS 2002-2007), an effort has been made to study the role of gravity waves in the generation of different phases SAO. Rayleigh Lidar observation over Gadanki has been utilized to estimate the gravity wave momentum fluxes and elucidate its seasonal variations. An extensive study has been carried out to estimate the relative contribution of gravity waves in driving SAO during three different cycles of SAO. It is quite interesting to note that gravity waves of periodicities 30 minutes- 4hour contribute about 30%-50% towards the mean flow acceleration. The contribution of gravity waves towards the mean flow acceleration varies from cycle to cycle. The detailed study will be presented.
DE: 1620 Climate dynamics (0429, 3309)
DE: 3334 Middle atmosphere dynamics (0341, 0342)
SC: SPA-Aeronomy [SA]
MN: 2007 Joint Assembly