Diurnal Variation of Turbulent Eddy Dissipation Rate Studied using 205 MHz Wind Profiler Radar

Cochin university of Science and Technology, India (10^o N, 77^o E) is operating the World's first Stratosphere-Troposphere Wind Profiler Radar operating at 205 MHz. This radar provides accurate three dimensional wind profiles for an altitude range of 315 m to 20 km. In this paper we present the diurnal variation of turbulent eddy dissipation rate in the lower troposphere (315m - 6 km) using the high vertical resolution (45 m) data generated from 205 MHz wind profiler radar during October 22-27, 2016. The dissipation rate has been derived using Doppler width method. The turbulent eddy dissipation rate exhibits a strong diurnal variation below 2 km and shows peak values during afternoon hours. The various factors such as surface temperature, vertical velocity, wind shear etc. which lead to the variability in the dissipation rate are investigated in detail. It is found that changes in the surface temperature and vertical velocity have a strong bearing on the variability of the eddy dissipation rate observed at the boundary layer. The turbulent dissipation rate derived from this radar data will be a valuable input for climate models. Moreover, this would aid in better understanding of the turbulent processes in the tropical latitudes in future.