Response of surface boundary layer parameters during the formation of thunderstorms over Cochin

• Published in: Journal of atmospheric and solar-terrestrial physics 2014-12, Vol.121, p.42-49
• Main Authors: Babu, C.A., Jayakrishnan, P.R.
• Format: Article
• Language: English
• Subjects: Atmospheric boundary layer; Atmospherics; Boundary layer; Enthalpy; Flux; Fluxes; Formations; Friction; Kinetic energy; Thunderstorm; Thunderstorms
• ISSN: 1364-6826; 1879-1824
• DOI: 10.1016/j.jastp.2014.10.001

In the present study we made a detailed analysis of the surface ABL parameters associated with three thunderstorms that occurred over Cochin during pre-monsoon season. The high-resolution sonic anemometer data can provide microscale evolution of the surface boundary layer processes. The parameters studied are momentum flux, sensible heat flux, Turbulent Kinetic Energy (TKE), friction velocity and variance of u, v, w, T. Momentum flux anomalously increases from 0.1Nm−2 to 1Nm−2 during the occurrence of thunderstorm. Correspondingly, sensible heat flux decreases anomalously to a value of −200Wm−2 from 10Wm−2. TKE increases abruptly to 3m2s−2 from 0.5m2s−2 during convective activity. Friction velocity also changes abruptly to 1ms−1 from 0.1ms−1. The thermodynamic parameters and stability indices were investigated prior to the occurrence of thunderstorms and found that the atmospheric characteristics were conducive for the formation of convective activity. •The study brings out the response of surface boundary layer parameters during the occurrence of thunderstorms over a tropical station utilizing fast response sensor data from a sonic anemometer.•The microscale evolution of the surface boundary layer features is examined further with the 1min averaged data during the formation of thunderstorm from the sonic anemometer.•The thermodynamic parameters and stability indices derived from radiosonde data were also studied during the occurrence of thunderstorm to identify the thermodynamic structure of the atmosphere.