Exploring the Trends of Aerosol Optical Depth and Its Relationship with Climate Variables over Saudi Arabia

Frequent dust storms, industrial emissions, and other factors raise aerosol levels over Saudi Arabia in ways that impact human health and the regional climate. Using the satellite data product of the Moderate Resolution Imaging Spectroradiometer (MODIS) from 2001 to 2023, this novel study focuses on the spatial patterns in Aerosol Optical Depth (AOD) and its relationship with climate variables across Saudi Arabia by adopting the pixel scale Geographically Weighted Regression (GWR) modelling. Notable increases in AOD are observed from 2001 to 2010 (0.03197/year, or 6.93%), from 2011 to 2015 (0.025/year, or 3.76%), and from 2021 to 2023 (0.049/year, or 10.78%). However, a smaller increase of 0.011/year (1.61%) is observed between 2016 and 2020, likely due to COVID-19 emissions control measures. The average values of spatially varying GWR coefficients illustrate how climate factors affect aerosol optical depth over Saudi Arabia. For example, AOD tends to increase (positive relationship) with atmospheric pressure across the majority of regions examined, with the area average coefficient values of 0.02821. This implies that for every unit increase in pressure, the AOD column value increases by 0.0282/year. Conversely, AOD shows inverse (negative) association with temperature across most areas, with the area average values of − 0.01737. Temperature and pressure show a stronger correlation, with wind speed, incoming solar radiation, humidity, and rainfall following in significant associations. The seasonal GWR analysis shows summer as dominant in the concern relationship. These findings offer valuable insights for policymakers to monitor AOD and manage air quality in Saudi Arabia, as well as to improve aerosol measurement techniques.