Effects of Cloud Seeding on Hydrological Processes, Air Quality and Particulate Matter Dynamics: A Case Study in San Angelo, TX, United states.

Cloud seeding is a weather modification technique aimed at enhancing precipitation from clouds by introducing substances that act as ice nuclei or cloud condensation. This process involves dispersing materials, such as silver iodide or dry ice, into clouds to stimulate the formation of ice crystals or water droplets, ultimately increasing rainfall or snowfall. Space-borne and ground-based data are used to investigate the environmental effects of cloud seeding on air quality and Particulate Matter with a diameter of 2.5 micrometer or less (PM2.5) and Particulate Matter with a diameter of 10 micrometer or less (PM10). United States, China, and the United Arab Emirates are considered for this work. Evaluation of cloud seeding’s impact on hydrological processes in selected watersheds located in Texas, United States was done to analyze changes in precipitation, runoff, and water availability. Long-term statistical analysis of aerosol optical depth (AOD), Ångström exponent (AE), precipitation, and particulate matter (PM) was performed. Meanwhile, meteorological data including temperature, humidity, pressure, and wind speed/direction are analyzed. Air quality conditions before, during, and after cloud seeding missions are tested using ground monitoring stations. Data from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra satellite were also used to perform a statistical correlation between aerosol optical depth (AOD) and ground PM observation. An increase in PM concentration was observed during the cloud seeding missions period, which indicates a possible effect of silver iodide crystals released during the missions by increasing the concentration of PM in the air. The study found that cloud seeding missions have a possible effect on increasing PM10 compared to PM2.5 concentration, which points to the possible effect of meteorological conditions on washing out silver iodide particles fired during the missions.