To investigate the synoptic mechanisms underlying a rare, widespread floating dust weather process in Guangdong Province during 12~16 April 2025, analyses were conducted using multi-source integrated observational data and reanalysis data. The results reveal:The cold front guided by the East Asian trough generated a dust area in southwestern Mongolia and drove it southward into Guangdong Province. Under the influence of dust, PM10 concentrations exceeded standards across all 21 cities in Guangdong, resulting in a total of 54 polluted cities (Including 6heavy pollution). On April 13, provincial average PM10 concentration reached 305.2μg/m3, 2.4 times the magnitude of the second-highest concentration since 2014. Notably, Guangzhou registered the highest daily average PM10 concentration (400μg/m3), significantly exceeding levels observed during the dust intrusion event affecting Guangdong in 2009. Climate analysis of the dust source region revealed that influenced by northwesterly flow ahead of a ridge, the cumulative precipitation in most parts of western Mongolia from February to March was below 10mm, significantly lower than the historical average for the same period. This resulted in soil moisture dropping to the fourth lowest level in the past 30 years, creating conducive underlying surface conditions for dust emission. Analysis of the dust transport process identified that the cold front generated the strongest northerly winds in the Nanling Mountains region in the past three decades. Driven by extreme winds, dust particles were carried directly across the Nanling Mountains andtransported southwards into Guangdong Province. Backward trajectory analysis indicated that dust particles reaching the four major regions of Guangdong were initially transported southward from Inner Mongolia to Hubei Province. Subsequently, they followed three distinct pathways (northern, northeastern, and northwestern routes) southward, traversing mountainous terrain of varying elevations to enter Guangdong, ultimately causing the extensive floating dust event.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |