Characteristics of rain events of different durations at a high-altitude site in the Western Ghats of India

We report duration-related properties of rain events at a high-altitude site in the Western Ghats (WG) of India during the summer monsoon (June–September) season. Duration of rain events is inferred from disdrometer data collected during the years 2015–18. Vertical profiles of events of different durations are studied using data of an X-band radar available for 2017–18 monsoon seasons. Durations of rain events span from 0.1 to 160 h. Rain intensity (i.e., rain rate), mass weighted drop diameter, and rain liquid water content decrease with duration up to 1 h, remain steady between 1 and 20 h, and then increase for larger durations. Rain drop number concentration shows an increasing trend with duration up to around 10 h and then decreases. Rain events are categorized into short- (< 10 h) and long-duration (> 10 h) events based on rain drop characteristics. The long-duration events account for ~ 15% of the total number of events and contribute ~ 75% to the monsoon rainfall. The long-duration events have association with the monsoon rainfall over the Indian core monsoon zone with a correlation coefficient of 0.77. The frequency distribution of 18 dBZ radar echo top height exhibits bimodal structure (around 2 km and 4 km) for both short and long events with a longer tail in the case of former. The study is primarily focused on the summer monsoon season; however, we also report the rain duration features during the pre-monsoon (March–May) season.