Annes, V H; Dr.Mohan Kumar, K(Cochin University of Science & Technology, June , 2000)
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Abstract:
The aim of the
present study is to understand the characteristics and properties of different wave
modes and the vertical circulation pattern in the troposphere and lower stratosphere
over Indian region using data obtained from the Indian Mesosphere-Stratosphere Troposphere
(MST) radar, National Center for Environmental Prediction/National
Centres of Atmospheric Research (NCEP/NCAR) reanalysed data and radiosonde observations.Studies on the vertical motion in monsoon Hadley circulation are carried out
and the results are discussed . From the analysis of MST radar data, an
overall picture of vertical motion of air over Indian region is explained and noted that
there exists sinking motion both during winter and summer. Besides, the study shows
that there is an anomalous northerly wind in the troposphere over the southern
peninsular region during southwest monsoon season.The outcome of the study on intrusion of mid-latitude upper tropospheric
trough and associated synoptic-scale vertical velocity over the tropical Indian
latitudes are reported and discussed . It shows that there is interaction
between north Indian latitudes and tropical easterly region, when there is an eastward
movement of Western Disturbance across the country. It explains the strengthening of
westerlies and a change of winter westerlies into easterlies in the tropical troposphere
and lower stratosphere. The divergence field computed over the MST radar station
shows intensification in the downward motion in association with the synoptic
systems of the northwest Indian region.
Description:
Department of Atmospheric Sciences,
Cochin University of Science and Technology