A Balloon-Borne Experiment for Quasi-lagrangian Frame of Reference Measurements of Intrinsic Frequency Spectrum of Gravity Waves in ihe Stratosphere

In the present communication, first results from an experiment to measure intrinsic frequency spectrum of atmospheric gravity waves using balloon-borne quasi-Lagrangian frame of reference observations in the mid-stratosphere over a tropical station, Hyderabad (17.4°N, 78.2°E) are discussed. A zero-pressure poly­ethylene balloon with GPS-sonde payload was drifted at ~31 km altitude for a horizontal distance of ~100 km for measuring pressure, wind and temperature at 1 sec temporal resolution. The measured altitude of the balloon showed variability within ±100 m, thus ensuring a near horizontal drift. These observations are used to estimate the intrinsic frequency spectrum of gravity waves in the mid-stratosphere over an Indian observational site. The successful experiment has opened up a new avenue for studying not only the stratospheric gravity wave dynamics, but also for exploring the hori­zontal mapping of stratospheric trace gases.