Statistical Analysis of Nocturnal Atmospheric Ducts in Fuzhou Based on Radiosonde Observations

Based on the nocturnal high-altitude radiosonde observation data collected in the coastal area of Fuzhou from 2018 to 2020, the occurrence patterns and characteristic parameters of surface ducts and elevated ducts in different seasons were statistically analyzed. The results indicate that atmospheric ducts in the coastal area of Fuzhou mainly occur from May to November each year. The probability of occurrence of atmospheric ducts at night in summer is about 70% (except for June), and about 50% in winter. Affected by the rainy season, the probability of occurrence of atmospheric ducts in June is significantly lower than that in other summer months, at about 50%. In addition, the occurrence frequency of elevated ducts is much higher than that of surface ducts. Elevated ducts account for about 94.8% of the total duct occurrences, while surface ducts account for 4.2%. Surface ducts mainly occur at height levels below 100m, with relatively weak overall intensity, and the occurrence frequency in summer is significantly higher than that in winter. Elevated ducts are mainly weak ducts, and strong ducts mainly occur in summer and autumn. Elevated ducts mainly occur at height levels between 1000m and 4000m, accounting for about 79%. The thickness of most elevated ducts is less than 100m, accounting for about 65%, and the proportion of elevated ducts with intensity less than 10M units is 87.5%.