1. Strong typhoon is a huge energy pool, and its wind speed is above 17m/s, even above 60m/s ... According to the measurement, when the wind reaches 12, the wind pressure per square meter on the plane perpendicular to the wind direction can reach 230kg.
2. Rainstorm typhoon is a strong precipitation system. When the typhoon lands, the rainstorm center can drop 100-300mm a day, or even reach 500-800mm. The floods caused by typhoons and rainstorms are the most dangerous disasters. Typhoon rainstorm is strong, flood occurs frequently, spreads widely, and is fierce and destructive.
3. Storm Surge The so-called storm surge means that when the typhoon moves to the land, due to the typhoon's strong wind and low air pressure, the sea water accumulates strongly in the direction of the coast, the tide level rises sharply, and water waves are overwhelming to the coast. The storm surge of a strong typhoon can raise the coastal water level by 5-6 meters. Storm surge meets astronomical high tide level, resulting in high-frequency tide level, which leads to tidal overflow, seawall burst, washed away houses and various building facilities, flooded towns and farmland, and caused a large number of casualties and property losses. Storm surge will also cause coastal erosion and land salinization caused by seawater intrusion.
After the typhoon landed, the wind was greatly weakened and the central air pressure rose rapidly due to the influence of rough ground friction. But at high altitude, strong winds are still blowing around the low-pressure center, and the high-temperature and high-humidity air from the ocean is still rising and condensing, constantly making raindrops. If humid air meets a mountain, the windward slope will force it to rise and condense at an accelerated speed, and the rainstorm there will be more violent. Sometimes after a typhoon lands, it's too tired to move. Not only does the wind decrease, but even the low-pressure center moves slowly and even stays in one place. In this way, the rainstorm poured in the same area for several days and nights, and the disaster was more serious. According to the report of the World Meteorological Organization, the number of people who die from tropical storms around the world every year is about 2,000-3,000. According to relevant data, the average annual economic loss caused by typhoons in countries along the western Pacific Ocean is $4 billion. China is also a country with severe typhoon disasters.
South China is most frequently affected by typhoons, with Guangdong and Hainan being the most serious. In some years, as many as 14 typhoons landed in these two provinces. In addition, Taiwan Province, Fujian, Zhejiang, Shanghai, Jiangsu and other provinces and cities are also frequently affected by typhoons. Some typhoons will go further inland after landing from the coastal areas of China. Among the countries along the western Pacific, there are about 7 typhoons landing in China every year, accounting for 35% of the total number of typhoons landing in this region. The impact of typhoon on the landing area is enormous. For example, typhoon 97 1 1 was generated at 8: 00 am in August 1997 and landed in Wenling, Zhejiang at 2: 00/30 on August 18. Shanghai immediately experienced a severe situation of "three encounters" with strong winds, heavy rains and high tides. There is 8- 10 gale in Shanghai and 59-87 mm rainstorm in some areas, 152. 1 mm. The tidal levels along the Yangtze River estuary and Huangpu River have both exceeded historical records. The tidal level at Huangpu Park Station is 5.72m, which exceeds the warning line1.17m, which is equivalent to the 500-year return period. There were 3 outlets in the urban flood control wall, nearly 20 overflows, 39 power lines were cut, 952 power grids failed, 70 streets were flooded, more than 500 houses collapsed and more than 2,000 houses were damaged. The affected farmland in the suburbs is nearly 500 square kilometers. As a result, the flight of 135 could not take off and land on time, and all 22 ferry routes were suspended. The direct economic loss is about 630 million yuan; /KOOC-0/994, 94/KOOC-0/7 typhoons landed in Rui 'an, Zhejiang Province, and the "wind and rain tides" met, affecting 7.5 million mu of crops in the province and killing/KOOC-0//KOOC-0/26 people; 1996, Typhoon No.9608 landed in Keelung, Taiwan Province Province and Fuqing, Fujian Province, causing more than 54 million mu of crops to be affected, and more than 700 people died in 10 provinces and cities. 1997, Typhoon 97 1 1 landed in Wenling, Zhejiang Province and Jinzhou, Liaoning Province successively. 10 affected more than 6,543.8 billion mu of crops in many provinces and cities, with 240 deaths. 200 1 Guangxi was hit by two typhoons "durian" and "ute" continuously, and there was a large-scale rainstorm or heavy rain. Tens of millions of people in 48 counties and cities in the region were affected, and more than 400,000 people were once trapped by floods.