Characteristics of tropical easterly jet over Gadanki: Comparison with radiosonde and rawinsonde

130-139Wind velocities obtained from the Indian mesosphere, stratosphere and troposphere (MST) radar (for about three years) are used to study the characteristics of tropical easterly jet (TEJ) over a tropical station, Gadanki (13.47° N, 79.18°E). The TEJ is active over the site during the south-west monsoon (June, July and August). The average zonal winds observed over the observing sites are westerlies up to 8 km and become easterlies above 8 km with maximum winds (~ 40 m/s) occurring at around 16 km height. The characteristics of TEJ, i.e., maximum zonal wind, height of maximum zonal wind, height of maximum shear and refractivity structure constant, are determined. The characteristics of TEJ over the observing site are compared with those estimated from the nearest radiosonde and rawinsonde observations. Special emphasis has been given to the simultaneous MST radar and radiosonde observations, which are carried out to understand the effect of temperature, humidity gradient and wind shear in the formation of the turbulent layers near TEJ zones. These regions of intense turbulence are identified during the observation period with N2 and Rj values close to or less than 0.25 (N being the Brunt Vaisala frequency and Rj, the Richardson's number, respectively)