Exploring the dynamics of the Atmospheric Boundary Layer over the Western-Indian region: Insights and Implications.

The Atmospheric Boundary Layer (ABL) represents the critical interface between the Earth's surface and the free atmosphere, playing a pivotal role in shaping weather patterns, air quality, and the dispersion of pollutants. This study comprehensively investigates the ABL dynamics over the Western-Indian region during 2019-2023. Continuous observation of ABL is made over the Western-Indian region's three locations: Ahmedabad, Mount Abu, and Udaipur. Ahmedabad (23.02° N, 72.57° E) is a highly polluted urban location in the Indian state of Gujarat with a hot, semi-arid climate, while Mount Abu (24.59° N, 72.71° E) is a high-altitude location in the Aravalli range of mountains in Rajasthan. On the other hand, Udaipur (24.58° N, 73.71° E) is close to the desert region in Rajasthan, surrounded by lakes and having a hot semi-arid climate. The ABL is continuously monitored over these stations using a ground-based Ceilometer lidar. By analyzing observational data collected from diverse geographical locations, we seek to identify regional variations in ABL characteristics and their consequences on local weather systems. Results indicated a large winter-summer difference in ABL over Ahmedabad, with summer Boundary Layer Height (BLH) exceeding winter BLH by 1–1.5 km. These differences were less over the Mount Abu and Udaipur region. The ABL usually collapses over all three study regions during monsoon and is thicker during the pre and post-monsoon. Ground-based observation of ABL using lidar has been compared with the radiosonde, satellite, and reanalysis datasets. The ERA5 reanalysis underestimated the BLH, especially the nocturnal boundary layer height. Due to the proximity to the Thar desert, the study sites witness dust storms. The study also investigated the impact of dust storms on the ABL. Through a combination of advanced measurement techniques, such as lidar and satellite observation, we aim to provide a nuanced understanding of the spatiotemporal variability of key ABL parameters. In conclusion, this study aims to contribute to understanding how the ABL responds to changing climate conditions and its role in modulating the Earth's energy balance. By enhancing our understanding of ABL dynamics, we can improve the accuracy of weather predictions, refine climate models, and develop strategies for mitigating the impact of air quality issues on human health and the environment.