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Forest lightning fire

The process of forest fire caused by lightning stroke. The main causes of forest fire caused by lightning stroke are thunderstorms, especially dry thunderstorms. There is less precipitation, increased ground temperature, reduced relative humidity and dry combustibles. Once lightning strikes, it is easy to catch fire and spread into disasters. Dry thunderstorm is a special weather condition, which is due to the hot and dry weather, the clouds in the upper air encounter cold air and rainfall. However, the rain has not yet fallen to the ground. Due to the high temperature of the lower surface, the rain is immediately evaporated into moist hot air, which rises into the air again. There will be thunder and lightning when it rains, accompanied by strong wind! An emergency can easily cause forest fires. Lightning is often accompanied by strong precipitation. If the rainfall and rain intensity reach a certain degree, the fire source caused by lightning will be extinguished automatically, and there will be no forest fire. However, under the warm and dry weather conditions, the precipitation can not reach the ground, or only a small part of the rainwater reaches the ground, and the rainfall is too small to extinguish the fire source. At this time, the fire source caused by lightning will spread into disaster. The possibility of fire caused by lightning is related to the meteorological conditions (such as temperature, temperature and wind speed) and vegetation conditions (combustible distribution, size and moisture content, etc.) where lightning occurs. If lightning occurs or is accompanied by precipitation after lightning, the possibility of fire spread is also closely related to rainfall and rain intensity. Forest fires caused by lightning are seasonal in specific areas. For example, the Daxinganling forest area is mostly from mid April to mid July. From late May to early June in the south of Yichun, the most lightning fires occurred in late June in Shanbei. Generally, there are more in the afternoon and less in the morning. The higher the latitude, the more lightning fires will occur. The lightning fire in the southern forest region of China is far less than that in the northern forest region. Lightning fire prevention in areas that are particularly prone to lightning fire, cloud ground lightning can be artificially eliminated to fundamentally eliminate lightning fire. At present, the following methods are adopted: first, the jet aircraft is used to land at a large angle to generate a towed downdraft, which can dissipate the clouds or reduce the cloud top, or the solid substances such as clay and salt powder are sown on the cloud top to cause downdraft and produce precipitation; The second is to destroy the electrification mechanism of thunderstorm cloud, and use aircraft to sow silver iodide to destroy the lightning cloud electrification mechanism; Third, eliminate or weaken the charge center in the cloud and inhibit the occurrence of lightning. For example, sow metal wires and other substances with good conductivity to weaken or neutralize the charge center in the cloud and reduce the electric field in the cloud, so as to eliminate lightning. Lightning in the cloud can also be induced by high-speed moving objects to destroy the electrification mechanism of thunderstorm cloud. If a small rocket with a long wire tail is fired from the ground to the cloud to induce lightning in the cloud, the cloud ground lightning can be eliminated, so as to avoid forest lightning fire. Eliminating lightning can completely eliminate lightning fire, but its cost is very high, such as aircraft interfering with thunderstorm clouds, lightning in clouds caused by small rockets, etc. At present, countries all over the world mostly use timely and effective fire fighting after the fire. Therefore, the prediction and prediction of lightning fire is one of the main measures of lightning protection and disaster reduction.
Author: Lin Qizhao