当逆温不明显或消失，低层转受东北干冷气流控制时，大雾过程结束；风廓线雷

When the temperature inversion is not obvious or disappears, and the lower layers are controlled by the northeast dry and cold airflow, the heavy fog process ends; the wind profile radar wind plume chart shows that the southerly wind blows near the ground before the fog appears, which is conducive to the transportation of warm and humid airflow. When the fog appears, the wind speed decreases continuously, and there is a certain warm advection effect. When the fog dissipates, the near-surface wind changes from the southeast wind to the northerly wind, and the wind speed gradually increases, which has a cold advection effect. <br>The overall simulation of the visibility calculated by the empirical formula is poor, but the simulation is better when the visibility is small, and the simulated fog appearance time and intensity are more consistent with the actual situation. <br>The temperature logarithmic pressure diagram of Haikou Station generally simulates the humidity conditions, temperature inversions and wind direction changes when heavy fog occurs. <br>Compared with the sea fog area that appeared on the 18th, the fog area and its evolution characteristics in the Qiongzhou Strait and the northwest of Hainan Island were simulated. <br>Due to the limited observational data of the sea fog process, this paper only analyzes the basic meteorological elements related to the sea fog, but the microphysical characteristics of the sea fog are still insufficiently understood. <br>Moreover, the characteristics of coastal fog are mainly analyzed, and the process of the formation, development and dissipation of the sea fog on the Qiongzhou Strait is still unclear. <br>The generation and maintenance of sea fog is related to sea temperature. Studies have shown that the rise and fall of sea temperature are very closely related to visibility (Zhang and Ren, 2010). The change of air-sea temperature difference affects the characteristics of the underlying surface, thereby affecting the turbulence characteristics of the boundary layer , Resulting in changes in environmental stability, thereby affecting the generation and disappearance of sea fog. <br>After that, the results of numerical simulation will be used to further analyze the generation and disappearance mechanism of heavy fog in the Qiongzhou Strait, and conduct numerical simulation experiments on the influence of sea temperature on sea fog, and study the influence mechanism of changes in the underlying surface on sea fog. Forecast provides technical support.

When the counter-temperature is not obvious or disappeared, the low-level transition by the northeast dry and cold air flow control, the fog process is over, the wind profile radar plume map shows that the fog appeared before the near-ground blowing southerly wind, conducive to the transmission of warm and humid air flow, when the fog appears the wind speed is decreasing, there is a certain warm flat current effect, the fog dissipated when the near-ground wind from the south-easterly wind to the northerly wind, wind speed gradually increased, cold flow.<br>The overall visibility simulation calculated by empirical formula is poor, but when visibility is small, the simulation time and intensity of fog simulation are more consistent with the reality.<br>The temperature versus pressure chart of Haikou station generally simulates the humidity conditions, counter-moderate and wind changes when fog occurs.<br>Comparing the fog areas that appeared on the 18th, the fog areas in the Qiongzhou Strait and the northwest of Hainan Island and their evolution characteristics are simulated.<br>Due to the limited observation data of sea fog process, this paper only analyzes the basic meteorological elements related to sea fog, and the microphysical characteristics of sea fog are not well understood.<br>The characteristics of coastal fog are mainly analyzed, and the process of generating, developing and dissipation of sea fog in the Qiongzhou Strait is not clear.<br>The generation of sea fog is related to maintenance and sea temperature, and some studies show that the rise and fall of sea temperature is closely related to visibility (Zhang and Ren, 2010), and the change of air and sea temperature difference affects the surface features of the lower pad, thus affecting the turbulence characteristics of the boundary layer, causing changes in environmental stability, thus affecting the life and loss of sea fog.<br>After that, the results of numerical simulation will be used to further analyze the mechanism of fog in the Qiongzhou Strait, and the effect of sea temperature on sea fog will be numerically simulated, and the effect mechanism of the change of the lower pad surface on sea fog will be studied to provide technical support for the prediction of sea fog.

When the inversion is not obvious or disappeared, and the low layer is controlled by the Northeast dry and cold air flow, the fog process ends; the wind profile radar wind plume map shows that before the occurrence of heavy fog, the southerly wind is blowing near the ground, which is conducive to the transportation of warm and wet air. When the fog appears, the wind speed decreases continuously and has a certain warm advection effect. When the fog dissipates, the near surface wind changes from southeast wind to northerly wind, and the wind speed increases gradually with cold Advection.<br>The simulation of visibility calculated by empirical formula is generally poor, but it is better when the visibility is small. The occurrence time and intensity of fog simulated are in good agreement with the actual situation.<br>The temperature logarithmic pressure diagram of Haikou station can simulate the humidity conditions, inversion and wind direction changes when fog occurs.<br>Compared with the sea fog area which appeared on the 18th, the fog area and its evolution characteristics in Qiongzhou Strait and Northwest Hainan Island are simulated.<br>Due to the limited observation data of the sea fog process, this paper only analyzes the basic meteorological elements related to the sea fog, but the micro physical characteristics of the sea fog are not well understood.<br>The formation, development and dissipation process of fog in Qiongzhou Strait is still unclear.<br>The generation and maintenance of sea fog is related to sea surface temperature. Some studies have shown that the rise and fall of sea surface temperature is closely related to visibility (Zhang and Ren, 2010). The change of air sea temperature difference affects the underlying surface characteristics, thus affecting the turbulent characteristics of boundary layer, resulting in the change of environmental stability, thus affecting the generation and dissipation of sea fog.<br>After that, we will use the results of numerical simulation to further analyze the formation and dissipation mechanism of fog in Qiongzhou Strait, and conduct numerical simulation experiment on the influence of sea surface temperature on sea fog, and study the influence mechanism of underlying surface change on sea fog, so as to provide technical support for the prediction of sea fog.<br>