Climatological features of high temporal resolution rainfall over the Hyderabad city, India

Abstract

High spatial variability and continuous evolution of a city's land use and land cover makes the city's rainfall mechanism more complex and dynamic, thus climatological rainfall features have both scientific and engineering relevance. A high-resolution hourly rainfall data from 37 Automatic Weather Stations (AWSs) of the Hyderabad city (an area of 650 km2) was considered. Rainfall analysis was carried out on an event-based approach from a total of 118 rainfall events. Rainfall frequency, depths and intensities were higher in the oldest region of the city for all seasons with exception of rainfall depth in summer. Diurnal variations in rainfall amount suggest large monsoon rainfall in the evening to midnight in fewer 1-hour spells. An increasing trend in rainfall depths and intensities highlights non-stationarity. In addition, decreased association among stations with increasing distance and increased spatial extent of precipitation with decreased spatial variability were observed. Further, enhanced rainfall activity in the city's region was observed as compared to its surrounding suburban region (has 33 AWSs). Results suggest significant rainfall variability across space- and time- scales, which may be associated with urbanization, and have great implications in a city's planning and development particularly under climate change and exponential urbanization context.