Assessment of difference in the atmospheric surface layer turbulence characteristics during thunderstorm and clear weather days over a tropical station

Abstract

The present study analyses the atmospheric surface layer characteristics (non-dimensionalised standard deviation of temperature and wind) during days of thunderstorm (DT) and clear weather days (CWD) during the months of pre-monsoon for years 2007, 2009 and 2010 at a tropical station Kharagpur (22°30′N, 87o20′E), India using the data sets collected by a 50-m instrumented tower. The study proposes site-specific relationships for thermal and mechanical characteristics of turbulence concerning atmospheric stability during DT and CWD during the pre-monsoon season. Although the analysis has not considered the data during the thunderstorm events (removed due to quality check), the relationships are different in CWD and DT cases. It is observed that during unstable stratification of CWD, values are less dispersed compared to the unstable region of DT. The study also reveals differences for stable stratification of DT and CWD days; even the thunderstorms are occurring during an unstable regime. The turbulence intensity for wind obeys the 1/3 power law, whereas for the unstable (stable) region of the temperature the − 1/3 (− 1) slope exists.