Perspectives on land breeze characteristics over Chennai

Abstract

An indigenous High Wind Speed Recorder (HWSR) which samples the wind direction and wind speed at one minute interval was installed at Chennai (Nungambakkam) in October 2009. The data obtained from such a modern observing system with high sampling frequency has been utilised to understand the land breeze characteristics over the station during January to March of the period 2010-12. Regularity observed in the transition of wind direction from easterlies to westerlies heralding the commencement of land breeze in the late night and early morning hours, frequency distribution of the hours in which land breeze occurs, the normal wind direction during steady land breeze and other interesting features have been presented. Analysis revealed that on 94 per cent of the occasions during the study period, LB was a regular and significant feature over Chennai Nungambakkam. The time of commencement of LB was in the early morning hours between 00 and 03 hours IST on 50 per cent of the occasions while time of decay of LB was between 08 and 11 hours IST in 73 per cent of the occasions.