Spatio-temporal evolution and driving mechanisms of dust activity in China's Northern Sandstorm Belt over the past 20...

The Northern Sandstorm Belt (NSbelt) of China is a key dust source region. Its dust activity directly affects regional ecological security and human settlements. Large-scale ecological restoration projects have significantly mitigated dust activity. However, the driving mechanisms of dust evolution under different precipitation backgrounds remain unclear. This study aims to systematically reveal PM10 evolution characteristics and dust activity driving mechanisms in the NSbelt from 2000 to 2023. The study first divided the NSbelt into four sub-regions: East, Central, Northwest, and Southwest. This division was based on geospatial location, desert distribution, hydrothermal conditions, and surface cover differences. Next, the study used the Mann-Kendall test and Sen's slope estimator to analyze PM10 evolution trends. A dust pollution identification method distinguished between dust-affected and dust-free days. Finally, a contribution attribution method quantified the relative contribution of fractional vegetation cover (FVC), precipitation (Pre), wind speed (Wind), and temperature (T) to dust activity. The results indicate: (1) PM10 across the entire region followed a significant fluctuating downward trend. The Central showed the most significant improvement (Sen's slope = -1.83). (2) The Southwest was an extreme dust pollution zone. It recorded 2487 cumulative dust-affected days. The East was the least affected region. It maintained over 345 dust-free days annually. (3) Precipitation strictly constrained the driving mechanisms. In the 400-600 mm zone, dust was most sensitive to vegetation (-0.31). In the 50-100 mm hyper-arid zone, dust was most sensitive to wind speed (0.20). (4) Increased FVC was the dominant factor in regional dust reduction (relative contribution: 44.26-77.51%). This study reveals differentiated driving mechanisms of environmental factors under various hydrothermal backgrounds. These findings provide a vital scientific basis for future regional dust prevention and control strategies.