A Study Of Gravity Wave Activities Based On Intensive Radiosonde Observations At Bengkulu During Ymc-Sumatra 2017

Gravity waves are generated from local regions such as convection, topography, jet stream and fronts. It is important to understand their activities because the quasi-biennial oscillation and general circulation in middle atmosphere are affected by their activities. However, the scale of gravity waves is too broad to understand their characters and activities in detail. The purpose of this study is to clarify three-dimensional dynamical circulation driven by gravity waves around the equatorial region. The Campaign of Years of Maritime Continent-Sumatra (YMC-Sumatra) has been operated since 2017 to expedite the progress of improving understanding and prediction of local multi-scale variability of the maritime continent weather-climate system and its global impact. We use intensified radiosonde observation data at Bengkulu during December 2017 and examine the relation between gravity wave activities and background state. The results showed that the heat flux of the gravity waves is proportional to the vertical shear of the background zonal wind. From the relation between gravity wave energy and Richardson number, it is suggested that the gravity waves having large amplitude modify the background state around 15 km.