What are the directions and paths of thunderstorms?

Thunderstorm is a discharge phenomenon in the atmosphere, which is generated between cumulonimbus clouds or clouds. Thunderstorms are often accompanied by strong winds, heavy rains, hail and other bad weather, and the powerful electromagnetic energy released by them will often cause great losses to people's lives and property, especially in today's increasingly popular electronic products, thunderstorms are more and more harmful to various microelectronic devices. Lightning protection and disaster reduction has become one of the important tasks of meteorological departments. Therefore, in ground meteorological observation, it is of great significance to correctly judge and record the direction and moving path of thunderstorms for exploring the law of local thunderstorm activity and disaster prevention and mitigation.

According to the observation of thunderstorms for many years, we believe that to correctly judge the direction and path of thunderstorms, we should start with the following points:

(1) It is necessary to know the general situation of the local climate during the thunderstorm peak period. Generally speaking, in late spring, early summer and early autumn, thunderstorms are often accompanied by weather systems, especially when cold fronts cross the border; In hot summer, the weather is hot and humid, and thunderstorms often appear in local cumulonimbus clouds in the afternoon.

(2) Be familiar with the topographical features around the site. The appearance direction and moving path of thunderstorms are greatly influenced by topography. Therefore, only by being familiar with the terrain and rules can we reduce the misjudgment of thunderstorm system.

(3) Memory observation of the span of the target around the field of vision. The observation point of thunderstorm is fixed at a certain point in the observation field, just like clouds and visibility. The eight directions of a thunderstorm are determined by the degrees of the central angle centered at this point (0 degrees due north, and an azimuth every 45 degrees). The arc length corresponding to the central angle is almost the same as the distance between the two directions. The longer the arc length, the longer the distance between the two directions, and vice versa. Fuyang observation point is located in the flight area of Fuyang Civil Aviation Airport, and the surrounding area is open and flat. Obstacles are far away from the observation point, so the distance between the two directions is long, while obstacles around mountain and hilly stations are close, so the distance between the two directions is short. Thunderstorm is a sudden strong atmospheric discharge phenomenon, often accompanied by weather phenomena such as precipitation. It is impossible and unnecessary for observers to go to the observation field every time. Many times they can only observe in the nearby duty room, which is a distance from the observation point, so pay attention to the location of the temporary observation point. For thunderstorms with a long distance, it is not easy to be affected when determining their orientation, while the distance between the two directions of mountain stations is very short. When determining the location of nearby thunderstorms, if we don't know the difference between the target span of observation point location and the coordinate location determined by temporary observation points near the duty room, sometimes artificial orientation errors will be caused by different observation points.

(4) With the aid of cumulonimbus lateral displacement direction or lightning identification system. At present, many stations are close to the urban area, and the noise of the city often affects the orientation identification of thunderstorms. The orientation and moving direction of isolated cumulonimbus clouds can generally reflect the moving direction of thunderstorms. Therefore, the location and moving route of thunderstorms can be judged according to the direction of cumulonimbus clouds during the day, and the location of thunderstorms can be judged according to lightning at night. Generally speaking, the direction of lightning is the direction of thunderstorm. When cumulonimbus clouds appear in a large area, it is necessary to judge and distinguish the main part and the secondary part of the thunderstorm system (only the moving path of the main part is recorded). The main part of the cumulonimbus cloud is the part with high thunder frequency, loud sound, dark cloud bottom color and thick rain curtain. The frequency of bright lightning at night is high, mainly vertical lightning on cloudy days. Don't blindly record lightning or thunder when you see or hear it once or twice, which will easily lead to recording confusion and can't reflect the real situation of thunderstorm activity. At this time, it is necessary to observe more and continuously, and judge how many thunderstorm systems there are according to the continuous thunder or lightning in all directions. Only in this way can we accurately record the real situation of thunderstorm activity.