Record-breaking dust loading during two mega dust storm events over northern China in March 2021: aerosol optical and radiative properties and meteorological drivers

Abstract. Although a remarkable reduction in the frequency of sand and dust storms (SDSs) past several decades has been reported over northern China (NC), two unexpected mega SDSs occurred on 15–20 27–29 March 2021 (abbreviated as “3.15” “3.27” SDS events), which reawakened widespread concern. This study characterizes optical, microphysical, radiative properties aerosols their meteorological drivers during these events using Sun photometer observations Beijing comprehensive set multiple satellite (including MODIS, VIIRS, CALIOP, Himawari-8) ground-based CMA visibility network AD-Net) combined with atmospheric reanalysis data. Moreover, long-term (2000–2021) optical depth (DOD) dataset retrieved from MODIS measurements was also utilized to evaluate historical ranking loading NC events. During 3.15 3.27 events, invasion plumes greatly degraded large areas NC, extreme low 50 500 m recorded at most sites 15 28 March, respectively. Despite shorter duration event relative event, sun larger peak AOD (∼2.5) former than latter (∼2.0), mainly attributed short-term intrusion coarse-mode particles effective radii (∼1.9 µm) volume concentrations (∼2.0 µm3 µm−2) event. The shortwave direct aerosol forcing induced by estimated be −92.1 −111.4 W m−2 top atmosphere, −184.7 −296.2 surface, +92.6 +184.8 atmosphere CALIOP show that plume lifted an altitude 4–8 km, its range impact extended source eastern coast China. In contrast, lifting height lower confirmed lidar observations. MODIS-retrieved DOD data registered massive intense episode same period history 2 decades. These were associated both circulation extremes local anomalies favored enhanced emissions Gobi Desert (GD) across southern Mongolia NC. Meteorological analysis revealed triggered exceptionally strong Mongolian cyclone generated nearly location (along central plateau Inner Mongolia) conjunction surface-level cold high-pressure system rear, albeit differences magnitude spatial extent impact. GD, early melting spring snow caused near-surface temperature regions, together negative soil moisture decreased precipitation, formed drier barer surfaces, allowed for increased into strongly surface winds cyclone.