Observational studies on turbulent energy and its dissipation, drag, momentum and wind components during thunder and dust storm events at an Eastern Indian city, Ranchi

Abstract

Abstract Storms frequent eastern India in summer months. These storms when accompanied by lightning and hail destroy life and property. Observation based studies on these storms are limited and dynamics of the storms are not extensively studied. This study was aimed at analyzing thunderstorms and dust storms in Ranchi, India during summer month of May. Observational data was obtained from micrometeorological tower at BIT Mesra campus. Drag coefficient, roughness length, turbulent kinetic energy, momentum flux, friction velocity, dissipation of turbulent kinetic energy was calculated using the observational data for comparative analysis. Wind speed and wind direction were also recorded and wind rose diagram for all the days with thunderstorm and dust storm were prepared. The results indicated higher values of all parameters during thunderstorm days when compared to days with dust storms. The peaks in the values were observed whenever the thunderstorms commenced and squalls were observed. There were clear differences in days of thunderstorm and days of dust storm in regard to wind components, momentum exchanges and energy. Higher availability of turbulent energy dissipation was observed during days with thunderstorms. A clear day on the same month was also observed and lower values was depicted in the graph in comparison to thunderstorm or dust storm days. Rainfall recorded in the study period was 11.8 mm. This study provides insight into dynamics of the atmosphere during days of storms in Eastern India.