Boundary Layer Features of One Winter Fog in the Yangtze River Delta, China

Shen, Peifeng; Liu, Duanyang; Gultep, Ismail; Lin, Hui; Cai, Ninghao; Cao, Shi-Jie; Wang, Zida

doi:10.1007/s00024-022-03119-4

Cited by 6 publications

(2 citation statements)

References 32 publications

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“…Dhangar et al (2021) demonstrated that the radiative cooling at the surface and fog top can increase supersaturation and promote fog vertical development. Shen et al (2022) found that the different cooling rates at two nearby stations lead to a remarkable difference in fog formation time, fog duration and vertical extent. Sufficient water supply is also an important factor.…”

Section: Introductionmentioning

confidence: 98%

Effect of the boundary layer low-level jet on fast fog spatial propagation

Yan,

Wang,

Liu

et al. 2023

Atmos. Chem. Phys.

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Abstract. The spatiotemporal variation of fog reflects the complex interactions among fog, boundary layer thermodynamics and synoptic systems. Previous studies revealed that fog can present a fast spatial propagation feature and attribute it to the boundary layer low-level jet (BLLJ), but the effect of the BLLJ on fog propagation is not quantitatively understood. Here we analyze a large-scale fog event in Jiangsu, China, from 20 to 21 January 2020. Satellite retrievals show that fog propagates from the southeast coastal area to the northwest inland area with a speed of 9.6 m s−1, which is 3 times larger than the ground wind speeds. The ground meteorologies are insufficient to explain the fast fog propagation, which is further investigated by Weather Research and Forecasting model (WRF) simulations. The fast fog propagation could be attributed to the BLLJ occurring between 50 and 500 m, because the wind speeds (10 m s−1) and directions (southeast) of the BLLJ core are consistent with fog propagation. Through sensitive experiments and process analysis, three possible mechanisms of the BLLJ are revealed: (1) the abundant oceanic moisture is transported inland, increasing the humidity of the boundary layer and promoting condensation; (2) the oceanic warm air is transported inland, enhancing the inversion layer and favoring moisture accumulation; and (3) the moisture advection probably promotes low-stratus formation, and later it subsides to become ground fog by turbulent mixing of fog droplets. The fog propagation speed would decrease notably by 6.4 m s−1 (66 %) in the model if the BLLJ-related moisture and warm advections were turned off.

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Section: Introductionmentioning

confidence: 98%

Effect of the boundary layer low-level jet on fast fog spatial propagation

Yan,

Wang,

Liu

et al. 2023

Atmos. Chem. Phys.

Self Cite

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“…Due to slippery road conditions or hydroplaning on rainy days (Kim et al 2021), road accidents are two to three times more likely than in dry weather (Brodsky and Hakkert,1988) and the overall accident risk was found to be 70% higher than the value of normal conditions (Andrey and Yagar, 1993). Fog usually occurs in winter and has a great impact on transportation (Li et al, 2019;Liu et al, 2016;Shen et al, 2022). Low visibilities because of fog can affect the drivers' behavior and the road safety (Hassan and Abdel-Aty, 2011), and vehicle rear-end collisions on the highway commonly occur in foggy weather (Huang et al 2020).…”

Section: Introductionmentioning

confidence: 99%

A New Method for Calculating Highway Blocking due to High Impact Weather Conditions

Liu,

Jing,

Yan

et al. 2024

Preprint

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Abstract. Fog, rain, snow, and icing are considered to be the high-impact weather events often lead to the highway blockings, which in turn causes serious economic and human losses. At present, there is no clear calculation method for the severity of highway blocking which is related to highway load degree and economic losses. Therefore, the goal of this work is to develop a method to be used to assess the high impact weather effects on the highway blocking. Based on the K-means cluster analysis and the CRITIC (Criteria Importance through Intercriteria Correlation) weight assignment method, we analyze the highway blocking events occurred in Chinese provinces in 2020. Through cluster analysis, a new method of severity levels of highway blocking is developed to distinguish the severity into five levels. The severity levels of highway blocking due to high-impact weather are evaluated for all weather types. As a part of calculating the degree of highway blocking, a new method is proposed for China, and the highway load in each province is evaluated. The economic losses resulting from highway-blocking events caused by dense fog are specifically assessed. Results suggested that the highway losses caused by dense fog was the main contributor for highway blocking conditions and occur at about 43 %.

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