Climatology of Lower Tropospheric Turbulence at Kochi using S-T radar.

This study investigates the climatology of atmospheric turbulence, focusing on the dissipation rate of turbulent kinetic energy (ε) in the lower troposphere. Utilizing data from the 205 MHz S-T radar located in Kochi, Kerala, India, our examination extends to the lower troposphere, particularly the boundary layer characterized by meteorological factors such as temperature gradients, wind shear, and convective processes that contribute to turbulent air motion. Turbulence in the atmosphere can arise either thermally through convection-related instability or mechanically through phenomena like Kelvin–Helmholtz billows, the reversal or disruption of gravity waves, and inertial gravity waves. A thorough understanding and prediction of turbulence in this atmospheric layer are critical for ensuring the safety and efficiency of air travel and advancing our understanding of the intricate interplay of atmospheric dynamics. The study employs the spectral width method for estimating turbulence dissipation rate, accounting for broadening effects due to shear and beam. After filtering out convective data, turbulence dissipation rates are estimated over 6 years from March 2017 to December 2022 from a height of 0.4 to 5 km. Monthly median analysis reveals a subtle increasing trend in the lower troposphere, with a slope of 1.6 x 10^-3. The vertical distribution indicates maximum data in the range of -4.5 to 1.75 m² s^-3, exhibiting a decrease in ε with height. ε displays definite seasonal variations, with maximum values and the least variation occurring within a specific range in the monsoon season. Winter season marks the least turbulent season. The study also explores the periodicity of the turbulence dissipation rate in the study region.