Investigation of Rainfall over Indore from Surface Observations

Abstract

This study characterizes rainfall using surface-based instruments (i.e., Micro Rain Radar (MRR), Automatic Weather Station (AWS), Laser Precipitation Monitor (LPM), and LIDAR ceilometer) installed at the Indian Institute of Technology, Indore, Madhya Pradesh, India. A total of 16 rainfall cases, 14 in July, and two in August of the peak monsoon period are considered according to the data availability. The vertical profile of reflectivity for these days significantly indicates the presence of a melting layer around 5 km over Indore, below this height, the drops start falling with a velocity >5 m s−1. The variation for drop size distribution from LPM at the ground and from MRR showed that with height, the number concentration increased with a large number of small-sized droplets in abundance. The behavior and statistical observation of the Cloud Base Height (CBH) measurement is obtained from a LIDAR ceilometer over Indore, giving insight into multi-layer cloud bases as such cloud structures are found mostly in the monsoon season. CBH1 was noticed to occur for 75% of the observation period. A rather heavy rainfall was observed on the 21st July with 45 mm precipitation recorded, and the maximum rain rate reached up to 115.65 mm h−1. The percentage occurrence of CBH1 observed was more than 60 on that day. The sudden hourly rain event around 1500 IST decreased the temperature to 25 °C and raised the humidity. The wind speed recorded was in the range of 1–8 m s−1. During the period with no rain, the cloud height observed was around 4 km compared to the period with rain, where at lower elevations, high reflectivity was observed, and the height of the clouds ranged below 1 km. Validation of the instruments revealed that the LPM shows better correlation of 0.99 as compared to MRR (0.98). The study suggests that there is a need to investigate cloud characteristics from multi-sensor observations to improve our understanding of precipitation and cloud microphysics. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2026.