Variations in frequency and intensity of dust events crossing the Mongolia–China border

抄録

In this study, we investigated the spatiotemporal variations of border-crossing dust events (DEs), including floating, blowing dust, and dust storms between Mongolia (MG) and Inner Mongolia (IM), China using the ground-based observations from 91 synoptic stations across the Mongolian Plateau during 1977-2018. We defined the intensity of DEs (progressive and recessive) depending on the dust impact area (number of stations affected by dust) by dividing them into three categories: DEs, transported dust events (T-DEs), and severe transported dust events (ST-DEs). The results revealed that during 1977-2018, the frequency of DEs in MG was two times higher than in IM. Simultaneously, the frequency of DEs (dominated by dust storms) increased in MG, whereas IM experienced a decrease in DEs (prevalent types of blowing dust). The T-DEs occurred 2.4 times higher than the ST-DEs over Mongolian Plateau. For the border-crossing DEs, transported dust storms were the dominant type. During 1977-1999, approximately 86% of DEs in IM originated from MG; however, this was decreased to 60% in the 2000s (2000-2018). The intensity of the border-crossing DEs originated from MGand the recessive T-DEs increased significantly since the 2000s, which were more significant than the progressive type.