A Fog Event off the Coast of the Hangzhou Bay during Meiyu Period in June 2013
| Autor: | Qi Wang, Darko Koracin, Shan-Hong Gao, Qian Wang, Su-Ping Zhang, Zhao-Xi Meng |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
010504 meteorology & atmospheric sciences
Planetary boundary layer Secondary circulation Diurnal temperature variation Coastal fog Land-sea thermal contrast Meiyu period 010501 environmental sciences Moisture supply 01 natural sciences Pollution Boundary layer Climatology Environmental Chemistry Environmental science Bay 0105 earth and related environmental sciences China sea |
| Popis: | A dense fog with the visibility less than 100 m over 6 hours occurred around the Hangzhou Bay off the coast of the western part of the East China Sea on 24–25 June 2013 during Meiyu period. This study focuses on the physical mechanism involved in the fog process by using in-situ observations and model. The analysis indicates that the land-sea thermal contrast played an essential role in the fog episode, while a weak low-pressure wedge associated with the Meiyu front and the diurnal variation in temperature provided background conditions. Induced by the strong land-sea thermal contrast, a secondary circulation formed in the lower levels of the atmospheric boundary layer (ABL) over the coast. The southeasterly wind and subsiding motion associated with the secondary circulation contributed to the moisture supply and the lowering of the boundary layer, favoring fog formation and maintenance. The fog maintained until the weakening of the temperature gradient between land and sea, when the downward flow was replaced by upward motion controlled by the approaching of a low-pressure center. These results are helpful for improving coastal fog forecast in Meiyu period and for our understanding of mechanisms involved in coastal fog processes. |
| Databáze: | OpenAIRE |
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