Monitoring cloud parameters using a ground- based airglow imager

Abstract

The current study investigates the application of the photogrammetric technique, commonly used for satellite measurements, on the All Sky Imager (ASI), which is used for night airglow observations from Kolhapur (16.8° N, 74.2° E), India. Using image processing methods, the current study spanning from the year 2016 to 2020 (March – May months) estimates the cloud speeds to range from 10 m s −1 to 18 m s −1 during the period under consideration. The slowest speed of 10 ± 3 m s −1 was evidenced in 2017, while it takes value of 15 ± 3 m s −1 over other years. The clouds are found to move in a south-westerly direction during the time period under consideration. The cloud cover fraction varies in between ~ 0.178 to 0.594 from 2016 to 2020. Our analysis indicates systematic changes in the pre-monsoon cloud fraction and direction of the cloud movement. The observed trend indicates that the monsoon pattern is somewhat changing.