Comparative Study on the Formation Mechanisms and Transport Characteristics of Three Spring Easterly Dust Events in Gansu Province
Online published: 2026-04-27
Against the backdrop of the ongoing“warm-wet transition”in Northwest China,dust events in Gansu Province have exhibited distinct regional characteristics. However,the formation mechanisms and transport pat‐ terns specific to easterly dust events remain inadequately studied. This study presents a comparative analysis of three representative spring easterly dust events in Gansu,integrating conventional meteorological observations, ERA5 reanalysis data,satellite remote sensing products,and HYSPLIT backward trajectory modeling driven by GDAS meteorological fields. We systematically examined the climatic preconditions,synoptic circulations,ther‐ modynamic and dynamic parameters,and transport characteristics. The principal findings are as follows: (1)The climatic preconditions for easterly dust events show no significant divergence from those of west-events. Prior to blowing dust events,near-surface temperatures were approximately 2 ℃ above the multi-year climato‐ logical mean,whereas preceding dust storms,anomalies reached 4~6 ℃. Regions with a precipitation deficit of 50% or lower relative to the historical mean were particularly prone to dust activation.(2)In contrast to the typi‐ cal“west-high,east-low”pressure pattern and frontal subsidence mechanism associated with west-events,east‐ erly dust events are governed by a northward-displaced 500 hPa trough and a surface“north-high,south-low” pressure configuration. ,resulting from the interaction between a cold anticyclone and a thermal low situated over southern Xinjiang or eastern Qinghai. As the system propagates eastward,the anomalously positioned cold front sweeps across northern Gansu,inducing dust outbreaks driven by easterly gales behind the cold front and along the high-pressure periphery.(3)Thermodynamic and Dynamic Features,easterly dust events are character‐ ized by strong cold air advection at 850 hPa(exceeding -4×10-5 K·s-1),positive vertical velocity greater than 0. 4 Pa·s-1 below 700 hPa,and positive horizontal helicity values surpassing 100 m2·s-2 in the middle and lower tropo‐ sphere. These signatures stand in clear contrast to those of westerly dust events,which are typically associated with negative vertical velocity and negative horizontal helicity.(4)In terms of dust sources and transport,easter‐ ly dust events are predominantly driven by external transport. During blowing dust events,remote sources con‐ tribute more significantly than proximal ones. Conversely,dust storms are mainly fueled by local deserts and ad‐ jacent arid regions,such as the Badain Jaran Desert and the Tengger Desert.
LI Wenjing, LIANG Xiaogang, GOU Shang, CHENG Rong, MA Li, QIN Haojun . Comparative Study on the Formation Mechanisms and Transport Characteristics of Three Spring Easterly Dust Events in Gansu Province [J]. Plateau Meteorology, 0 : 1 . DOI: 10.7522/j.issn.1000-0534.2025.00102
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