What is the cause of sea fog? In what season, sea fog mostly occurs in the morning?

Lead: In daily life, natural scenes are colorful, among which fog is a strange sight that everyone is familiar with. Sea fog is a kind of fog. Some friends in Bian Xiao don't know what season most sea fog occurs in the morning. What is the cause of sea fog? I hope you can finish reading this article carefully edited by Bian Xiao.

In what season, sea fog mostly occurs in the morning?

Sea fog mostly occurs in the morning of spring and summer. Sea fog is a phenomenon of water vapor condensation (blooming) in the upper and lower atmosphere of the ocean. Due to the accumulation of water droplets or ice crystals (or both), the horizontal visibility is reduced to below 1 km, and the thickness of fog is usually about 200-400 meters.

After the sea fog forms at sea, it will drift with the wind and spread downstream with the wind. In coastal areas, sea fog can go deep into the land, sometimes reaching dozens of kilometers. After landing, the sea fog still maintains the characteristics of sea fog, but under the influence of the new environment, it quickly degenerates and dissipates, or becomes low clouds. In the offshore area, although the landed sea fog dissipates continuously, new sea fog is constantly replenished from the sea, so sometimes the sea fog in the coastal area will last for several days.

Sea fog occurrence

Many people used to think that the relative humidity of fog should reach 100%, that is, it is saturated. Many observation results in recent years show that the relative humidity of sea fog may not reach 100%, and sometimes fog will appear when the relative humidity is above 80%, which may be related to a large number of condensed nuclei (salt particles) with strong hygroscopicity at sea.

The relationship between relative humidity and fog also has certain diurnal variation characteristics. Fog, which usually appears in the early morning and at night, mostly appears when the air is at or near saturation. With the gradual decrease of relative humidity, the number of fog will decrease rapidly. When the relative humidity is lower than 95%, there will be no fog. At noon, the number of fog does not change much with the decrease of relative humidity. When the relative humidity is as low as 88%, there will still be fog.

Fogging in strong inversion layer is a condensation phenomenon when the atmosphere is in a stable stratification state. In the process of sea fog formation, there is always an inversion layer in the lower atmosphere, which, like an invisible cover, blocks the diffusion of water vapor to the sky, inhibits the convection development of the lower atmosphere, and accumulates water vapor and condensation nodules at low altitude, which is extremely beneficial to the formation of fog. In stable fog, the most typical vertical temperature profile is that the fog layer presents weak cooling isotherm, and above it is inversion temperature. The occurrence rate of fog layer inversion in advection fog is about 90%. Usually, the stronger the inversion intensity, the greater the inversion layer thickness, and the common inversion layer thickness is about 400-500 meters.

The sea is not a new atmospheric phenomenon, but a sea fog.

Many people are unfamiliar with the word "Hai Hao", but as early as 20 15, the word "Hai Hao" appeared in newspapers and periodicals.

20 15 1 1 year 10, the media in Dalian, Liaoning Province published "The Wonders of the Sea on Zhangzidao". After searching, the research team of China Ocean University found that this report is the first time to use the word "Hai Hao" in China.

During the cold wave weather that swept through China in early October, 2002 1,1,the word "haihao" was widely spread in various media, which attracted great attention from the research team of sea fog in China Ocean University. After questioning and extensive verification, the team members agreed that the word "Haihao" is a local saying of Zhangzi Island in Dalian, and "Haihao" is only a phonetic symbol, which is not suitable for expressing meaning, let alone a technical term. It is found that "Haihao" is not a new sea surface atmospheric phenomenon, but a advection evaporation fog (or steam fog) that occurs in the offshore of northern China under severe cold weather conditions.

The Yellow Sea is a world-famous place where sea fog occurs, and the research on sea fog is a main direction of the research team led by Fu Gang. At present, the numerical forecasting system of sea fog has been established and widely used in meteorological and marine business departments.

The team members analyzed and studied the pictures and video reports of the so-called "Hai Hao" phenomenon at the beginning of 2002 1 and1,and combined with the related contents of the book "Sea Fog" written by Professor Wang, the earliest scholar of sea fog in China and a pioneer of marine meteorology, formed the Interpretation of the word "Hai Hao".

In fact, the necessary condition for this atmospheric phenomenon is that cold air far below the temperature of seawater passes through the warm sea surface, and the water vapor quickly condenses into tiny water droplets after encountering the cold air, and floats near the sea surface to form fog. Because the cold air from the north is dry as a whole, the fog only exists near the water vapor-rich sea surface. Under normal circumstances, when the temperature is below -30℃, ice fog often appears, with water fog above-10℃ and ice-water mixed fog between -30℃ and-10℃.