![]() ![]() based on the conventional lidar technology for cloud height and shape determination. In 2018, a visibility lidar instrument was used for a sea fog monitoring test in the Beilun area of the Ningbo Port by the Ningbo Meteorological Bureau and Darsun Laser Technology Co., Ltd. Therefore, to improve the meteorological services, the Ningbo Meteorological Department built a modern marine monitoring system in the port. Consequently, the meteorological fine (i.e., comprehensive and targeted) service demands, including the routing of ships, wharf stop, and port area operation, are very high, especially when sea fog 10 – 12 is present. In 2020, the cargo throughput in this port was estimated at 1.172 billion tons, ranking it the first in the world for the 12th consecutive year. The Ningbo Zhoushan Port in China comprises 19 areas, including Beilun, Yangshan, Liuheng, Qushan, and Chuanshan. Recently, lidar has been used for aviation research and operations, including marine fog studies. Lidar can also provide horizontal wind profiles to analyze turbulence and gust at low elevation angles. Lidar-based observations are typically used to obtain Doppler wind speed. Conversely, as lidar is characterized by good monochromaticity, strong directionality, and high coherence, it has been widely employed in environmental and meteorological monitoring as well as other fields. However, because of the complexity of sea channel fog, the forward scatter sensor exhibits limitations in monitoring, making it impossible for the sensor to provide early warning observation under highly variable sea fog conditions. During a systematic sea fog occurrence (i.e., a wide range of fog within a weather system, such as advection fog), adequately referenced monitoring data from a forward scatter visibility sensor 6, 7 can represent the surrounding area. 2 Over the years, the meteorological service in the wharf of the Ningbo Zhoushan Port in China has depended on a few scatter-type visibility sensors to acquire sea fog and associated data. 5 However, accurate fog forecasting/nowcasting is difficult because of the inherent difficulties in detecting fog. Accurate forecasts could help to mitigate the financial losses and reduce injuries caused by fog. The horizontal range and vertical height of the fog change widely and rapidly. 4 The various fog types include advection fog, mixed fog, radiation fog, and terrain fog. 2 Generally, the thickness of sea fog ranges from 200 to 400 m however, it can sometimes be over ∼ 500 m. Losses related to fog and low visibility have become comparable to those caused by other weather events, such as tornadoes or hurricanes. 3 In navigation, sea fog is a disastrous weather event that substantially affects the safety of ships. 1, 2 Fog and its effect on visibility (Vis) have significant impacts on our daily lives. It can also affect industries such as shipping and oil platforms, where it has been known for stubborn coastal fog to disrupt productivity for long periods.Fog is characterized by the suspension of very small droplets and ice crystals of water in air that results in a visibility of < 1 km (5/8 of a statute mile). The sudden onset of coastal fog can sometimes be dangerous, causing disorientation as it dramatically reduces visibility. However, if the land temperature is cooler, the fog can linger for a longer time.Ĭoastal fog might also refer to pre-existing fog which is transferred from a distant source and is simply moved to the coast by prevailing weather patterns. If the land temperature is warm, the fog can quickly dissipate as the parcel of air warms. ![]() ![]() If, as is common along the UK's east coast, the winds blow in from the east, the fog will often rapidly cover the coast in a blanket of fog. The impact, location and movement of coastal fog depend upon a number of conditions, including wind strength, wind direction and land temperature. This forces the warm air to condense, forming tiny particles of water which forms the fog that we see.Ĭoastal fog usually occurs in the spring and summer months when conditions begin to warm up but the sea (which warms more slowly) stays relatively cold. When this happens, the cold air just above the sea's surface cools the warm air above it until it can no longer hold its moisture. In the UK, the most common occurrence of coastal fog is when warm air moves over the cool surface of the North Sea towards the east coast of the UK. How does coastal fog form?Ĭoastal fog is usually a result of advection fog which forms when relatively warm, moist air passes over a cool surface. ![]() In eastern Scotland, it is known locally as Haar whilst in eastern England, the coastal fog is referred to as Fret. Coastal fog is a regular occurrence along the eastern coast of the UK and is most common during spring and summer. ![]()
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