Identification of Potential Aerosol Sources over an Urban Region on the Monsoon-Dominated Southern West Coast of India
摘要
Identifying the sources and variability of atmospheric aerosols is essential to understanding their impact on climate, air quality, and the health of living beings. Here, an attempt has been made to determine the sources and seasonal and interannual variability of aerosols over the monsoon dominated region of Mangaluru. At the ground surface, the daily mass concentration of dust ranges from 0.94 to 89.6 µg m⁻3, with an annual mean of 22.8 ± 15.8 µg m⁻3. In contrast, black carbon (BC) concentrations range from 0.12 to 2.74 µg m⁻3, with a mean annual value of 0.82 ± 0.59 µg m⁻3. A significant increasing trend in AOD is observed, with percentage changes per decade estimated using linear regression applied to the seasonal mean AOD time series, showing the strongest increase during winter (≈32.8% per decade) and spring (≈17.9% per decade), while summer exhibits a nearly stable and insignificant change. This seasonal behaviour indicates that mineral dust, enhanced by long-range transport in summer and combined dust and smoke contributions in spring, plays a more dominant role in AOD variability than black carbon. Integrated analyses using CALIPSO vertical profiles and HYSPLIT back-trajectories revealed new findings of seasonal aerosol layering and long-range dust transport over Mangaluru, offering in-depth insights into aerosol–monsoon rainfall interactions, radiative forcing, and coastal air-quality management.