Dominant circulation pattern and moving path of the Mongolian Cyclone for the severe sand and dust storm in China

Abstract

Severe sand and dust storm (SDS) is one of the major meteorological disasters in northern China. During 2000–2023, a total of 37 severe SDS events were monitored by the China Meteorological Administration and 34 of them occurred in the boreal spring (March to May). In this study, the 34 cases are analyzed to reveal their spatio-temporal features. The results indicate that there are two high-frequency centers. One is located in the Tarim Basin in northwestern China and the other is located in the central-western part of Inner Mongolia in northern China. In the 21st century, the duration of the severe SDS shows a clear interannual variation with an average of 3.5 days in 2000–2006, 2.7 days in 2007–2015 and 4.6 days in 2016–2023, respectively. Moreover, it occurs mainly in early spring in the third period, whereas it can occur throughout spring in the first and second periods. The composition of the general circulations for these 34 cases indicates that the simultaneous dominant pattern is a “positive-negative-positive” wave structure in the mid-high latitudes of Asia, with a cyclonic circulation (a deep trough) over the southern part of Russia to Mongolia, a major anticyclonic circulation (a ridge) over the eastern Europe to the west of Central Asia and a secondary anticyclonic center over northeastern China to the Korea Peninsula and Japan. The “positive-negative-positive” pattern enhanced the Mongolian Cyclone by increasing the zonal pressure gradients to both its west and east sides. Both the composition and typical case studies indicate that the eastward movement of the Mongolian Cyclone plays a dominant role in causing the severe SDS.