China Weather Network News In September this year, three autumn typhoons "Xuanlannuo", "Plum Blossoms" and "Miaobo" were successively generated. Among them, the typhoon "Plum Blossoms" will land in the coastal areas of Zhejiang from the afternoon to night on the 14th, and will bring obvious wind and rain to some areas of East China, and severe rainstorms will occur in some areas. In the eyes of many people, summer is the most active typhoon and is also the most likely season for typhoons to cause disasters. In fact, the power and impact of autumn typhoon should not be underestimated. China Weather Network specifically counted meteorological data from 1949 to 2020 and found that there were more "harsh characters" in autumn typhoons.
Login time: Typhoons are still active in September. Autumn typhoons should not be underestimated
Usually, we call typhoons generated from June to August "summer typhoons", and typhoons generated from September to November "autumn typhoons". Statistics show that in the past 72 years, 833 typhoons have occurred in summer, which is the most active season for typhoons, and 821 typhoons have occurred in autumn, second only to summer.
Judging from the situation of logging in to my country, the influence of the autumn typhoon should not be underestimated. Data from 1949 to 2020 showed that on average, about 4.43 typhoons landed in my country each year, which is the season with the most typhoons landed in my country; and on average, 2.36 typhoons landed in my country each year, which is the second active season for typhoons; the average number of typhoons landed in spring and winter each year is less than 0.2.
In autumn, September was the most active, with an average number of logged in reaching 1.72, second only to August (1.94) and July (1.83), where typhoons are most frequent, with a small difference.
Intensity: There are many "harsh characters" in autumn typhoons, and super typhoons account for a high proportion of
Although the number of summer typhoons generated and logged in is the largest in the year, meteorological big data shows that autumn typhoons are more likely to produce "harsh characters". Between 1949 and 2020, super typhoons accounted for 27.9% of the typhoons generated in autumn, far higher than 18% in summer.
Judging from the intensity of the typhoon's first landing in my country, the autumn typhoon is significantly higher than the summer typhoon. In summer, typhoons mostly landed in my country at the level of tropical storm or strong tropical storm, and only 14.9% of them reached the level of strong typhoon or above; in autumn, this proportion reached 22.4%, significantly higher than in summer.
Impact: Autumn typhoon encounters cold air, disaster impact escalates
Historically, there have been several autumn typhoons that have had serious impacts on our country. The strongest typhoon that landed in my country in September was Typhoon No. 14 in 1973. According to the data of the Central Meteorological Observatory, Typhoon "Marge" landed in Qionghai, Hainan in the early morning of September 14. The maximum wind speed near the center was 60 meters per second, and the minimum pressure in the center was 925 hPa. According to Xinhua News Agency , the typhoon caused a total of 926 deaths, 1,690 serious injuries, 4,470 minor injuries in Hainan Province, and 126,000 houses collapsed, causing heavy losses.
In addition, the recent typhoon No. 14 of 2016 " Moranti " is also very powerful. After it landed in Xiamen , it advanced all the way northwest. The wind and rain clouds affected 11 provinces and cities including Fujian, Guangdong, Jiangxi, Zhejiang, Shanghai, Jiangsu, etc., with strong winds and heavy rainstorms.
Why is the autumn typhoon so destructive? Shi Yan, a meteorological analyst at China Weather Network, introduced that starting from the vernal equinox, the direct sunlight point moves from the equator to the Tropic of Cancer, heating the tropical oceans of the northern hemisphere. The sea water heat continues to accumulate, and the sea temperature usually reaches its highest from August to September. High sea temperatures are conducive to typhoon generation and energy enhancement. At the same time, from the end of August to the beginning of September, cold air began to become active, increasing the pressure gradient, and increasing the wind speed near the center of the typhoon is also conducive to the increase in typhoon intensity. Therefore, in autumn, a higher probability of strong typhoons or super-strong typhoons occur.
Shi Yan reminds that the "ruthless" of autumn typhoons not only reflects the intensity of the typhoon, but also the impact of the disaster may also escalate. As the cold air gradually increases in autumn, typhoons are more likely to encounter cold air, and "Autumn Typhoon + Cold Air" is a terrible combination. The two join forces often trigger violent precipitation, resulting in greater disasters.
For example, Typhoon No. 13, 2010, was generated in October and did not log in to Taiwan directly. It drilled into South China Sea from Bashi Channel , and then went north to Zhangpu, Fujian.The large amount of warm and humid air transported by the typhoon circulation encountered cold air from the north to the south, and the impact of the terrain lifting of the central mountain range in Taiwan, resulting in more than 1,000 mm of precipitation in Suao, Yilan, eastern Taiwan, and the collapse of the Suhua Highway , causing many deaths or disappearances.
Forecast difficulty: The path of autumn typhoons is changeable, and the prediction is more difficult.
Autumn typhoons are not only outstanding in strength, but also often change in the path. According to the "Typhoons in my country" compiled by the Central Meteorological Observatory in 2015, three typhoons were recorded in the "Typhoons with the most complex path", including Typhoons No. 16 in 1986, Typhoons No. 19 in 1991, and Typhoons No. 16 in 2001, Nari. Among them, "Nate" and "Lily" are both generated in autumn, and the life cycle of "Wayne" is also in late summer and early autumn.
1991 Typhoon "Nat" path map
2001 Typhoon "Nari" path map
2001 Typhoon "Nari" path map
0Autumn typhoon path is more complex and changeable, and is related to the weather system affecting autumn typhoons. Shao Peng, a meteorological analyst at China Weather Network, said that in autumn, such as westerly wind belt , subtropical high pressure, cold air, etc., these weather systems compete with each other without deciding their victory or defeat. It is like a "naughty child" being influenced and controlled by different "parents", so it becomes east and west, south and north, with strange and changeable paths, which greatly increases the difficulty of prediction. Whether in terms of the difficulty or power of forecasting, Autumn Typhoon is a very "ruthless character".
According to the forecast of the Central Meteorological Observatory, typhoon "Plum Blossoms" will land on the coast of Wenling to Zhoushan , Zhejiang from the afternoon to night on the 14th (typhoon level or strong typhoon level, 38-45 meters/second, 13-14); after landing, the "Plum Blossoms" will continue to move to the northwest direction, and the intensity gradually weakens.
Typhoon "Plum Blossoms" will bring strong winds and rain to some sea areas such as and East China Sea, the Yellow Sea, etc. There will be heavy to torrential rain in eastern East China, heavy torrential rain in some areas, and local heavy torrential rain. There will be strong winds of 6-8 levels along the coast of Zhejiang, Shanghai, and southeastern Jiangsu, with gusts of 9-11. Zhejiang, Shanghai, Jiangsu, Anhui, Shandong, Liaoning and other places need to make various emergency preparations for typhoon prevention. In addition, the path after the "Plum Blossom" lands is uncertain, and there may be stagnation and circumference in Jiangsu and Anhui in the later period. We need to be vigilant about the impact of continuous heavy rainfall. (Text/Zhang Hui, Wang Wenwen, Data Support/Shi Yan, Shao Peng, Design/Wei Lai, Ren Chengying)
Source: China Weather Network
