Cover News Reporter Bian Xue Trainee Reporter Ma Xiaoyu
The wind is not even, and the wind rises again. After the typhoon season began with "Terry" generated in mid-July, "Sura" just left, "Anemone" was connected, and soon after, "Little Dog" set off another storm, and although the number of typhoons that appeared in this year's "pile" was small, it was "rolled" to death.
Typhoon "Puppy". (Image source: Central Meteorological Observatory)
On average, the period of typhoon activity is the most active period from July to September of the year, and the number of typhoons generated and landed is the highest in the year, but this year, the number of typhoon generation and landfall is significantly less. As of mid-October, a total of 15 typhoons had been generated in the Northwest Pacific and South China Sea this year, compared with an average of about 25 typhoons a year.
Four typhoons that made landfall on the mainland this year reached super typhoon status
According to public data, from July to September this year, there were 11 typhoons in the northwest Pacific and the South China Sea, of which 5 made landfall on the mainland: 2304 Teli, 2305 Dusuri, 2309 Sura, 2311 Anemone, 2314 Puppies, not including 2306 Kanu, which made landfall on the mainland with a tropical depression. On average (1991-2020), 14.46 typhoons were generated from July to September and 5.66 landed on the mainland.
Although the number of typhoons generated is small, there are still many "conspicuous pack" typhoons that impress. For example, Typhoon "Du Surui", which made landfall in Fujian and then went north to create catastrophic effects, or Typhoon Kanu, which lived for 15 days on a long standby and then entered the northeast to create precipitation, as well as Typhoon "Sula" and Typhoon "Little Dog" of Guangdong Coastline Stroke Master 2.0 who drew a circle in place and described the Guangdong coastline, and even a "smuggling" typhoon "Dora" who came from the eastern Pacific Ocean not far away.
Not only are the paths peculiar and forecasts difficult, but this year's typhoon intensity is also very strong. Eight of the 15 typhoons generated so far this year have reached super typhoon level (6 of the 11 typhoons from July to September have reached super typhoon level), and of the five typhoons that made landfall on the mainland, the other four typhoons except Teli were the strongest to have reached super typhoon.
This is not a normal state. According to rough statistics, from 2000 to 2022, an average of 5 super typhoons will be generated every year. This year's super typhoon clearly exceeded the standard and was significantly destructive.
In early September, affected by Typhoon "Sea Anemone", heavy rainfall occurred in Fujian, Guangdong, Guangxi and other places, resulting in serious waterlogging.
"Anemone" Typhoon Path. (Image source: Central Meteorological Observatory)
From July 29 to August 1, Typhoon Du Surui traveled all the way north, and the residual circulation brought extreme rainfall to the Beijing-Tianjin-Hebei region with a historically rare extreme rainfall process.
Why is this year's typhoon so "rolled"?
Why are there so many typhoons this year and more energy? On October 13, the well-known popular science V "Zhongqi Ai" said in an interview with the cover news reporter that in fact, as of October 11, a total of 15 typhoons had been generated in the northwest Pacific, which was significantly less than the same period of the year.
"This year's typhoons are a false impression. However, this year's typhoons are indeed very strong, with average intensity and extreme intensity greatly exceeding the average, of which 8 super typhoons have reached 8, the most since 2016, and the super typhoon rate has reached more than 50%, one of the highest years in history. ”
Every typhoon that debuted this year should not be underestimated. "Super Typhoon Sura reached Category 17 or above, and walked out of the path along the Guangdong coastline, causing Hong Kong to issue Hurricane Signal No. 10; Super typhoon Anemone reached category 16, made landfall in Taiwan, Fujian and Guangdong, and maintained in South China for more than 10 days, causing extremely severe extreme heavy rainfall, the total rainfall exceeded Du Surui, which can be called this year's 'water king'. "According to Zhongqi Ai, not long ago, the super typhoon puppy reached level 16, and after landing in Taiwan, it cruised along the coast of Guangdong, leaving an amazing measurement of nearly 100 m/s, and suddenly turned north off the coast of Guangdong, causing Hong Kong, Zhuhai and Macao to unexpectedly rain heavily." It can be seen that this year's super typhoon is not only strong, but also has a long lifespan, full of personality and huge impact, so it is impressive, causing many strong impressions of this year's typhoon. ”
"Puppy" typhoon path. (Image source: Central Meteorological Observatory)
"Zhongqi Love" told the cover news reporter that behind the more super typhoons this year, two factors may have played an important role, one is the general ocean warming, the sea temperature does not move a large area of 30 degrees, it is difficult to think of a super typhoon; The second is the impact of El Niño. "In the El Niño context, typhoons originate easterly and tend to have a longer life and stronger intensity. If ocean warming continues, we may see more and stronger super typhoons in the future, and those previous typhoon records may soon be broken. ”
In July, the World Meteorological Organization announced that the equatorial Middle East Pacific Ocean had entered El Niño status and that an El Niño event of moderate or greater intensity would form this fall. Now, the El Niño status continues to develop, and the Nino3.4 sea zone indicator has exceeded 1°C for three consecutive months since June.
Statistics have found that among the typhoons that have landed on the mainland in recent years, typhoons of typhoon intensity and above are increasing. In particular, there have been 39 strong typhoons and above since 2004, accounting for nearly seventy percent (68%) of the total, of which 5 super typhoons made landfall on the mainland from 2014 to 2018.
"The formation of typhoons is affected by many factors, including SST, monsoon activity, and changes in the location and intensity of subtropical highs." Wang Weiyue, a meteorological analyst at China Weather Network, said. If the tropical ocean surface of the northwest Pacific Ocean and the South China Sea, where typhoons originate, are controlled by subtropical highs, convective activities will be inhibited, and the necessary conditions for typhoon formation will be lacking. If the monsoon is weak, the convective cloud activity will also be weak, which is not conducive to typhoon formation. These changes in the environmental field will be detrimental to the formation and development of typhoons.
In recent years, typhoons have shown a trend of becoming fewer and weaker
In fact, not only this year, since 2019, typhoon activity in the Northwest Pacific Ocean has been below average, whether it is the number of typhoons generated, the number of typhoons landing on the mainland or the cumulative cyclone energy index (ACE) are lower than in previous years, and the intensity of typhoons making landfall tends to be more average.
In 2020, a total of 23 named typhoons, only 5 landed on the mainland, the strongest landfall typhoon was the sixth "Mikla", 12 wind power landed in Zhangpu, Fujian, the annual ACE index was only 152.8, the fourth lowest data since 1949; the number of North Atlantic hurricanes in the same year broke the historical record.
In 2021, a total of 22 named typhoons, 6 landed on the mainland, the annual ACE index was 209.6, the strongest landfall typhoon was the sixth "fireworks", 13 wind power landed in Zhoushan, Zhejiang, which acted as a large pump of water vapor in the Pacific Ocean, condensed it into a jet stream, and sent to the North China Plain indirectly caused the heavy rainfall in Zhengzhou on July 20, causing serious losses; By 2022, there will be 22 named typhoons and 5 landfall on the mainland, and the annual ACE index will be -163.2, which is lower than in 2021.
Between 2019 and 2022, typhoon activity in the northwest Pacific was weak, mainly due to La Niña phenomenon, and North Atlantic hurricanes were more active, while the subtropical high over the northwest Pacific was southerly and inhibited typhoon formation and development by strong downdrafts.
It is not only typhoons that are decreasing in number and weakening in energy. Statistics show that from 2012 to 2022, the number of heavy rainfall in the mainland oscillates, and there is no obvious increase trend. And since 2019, the number of heavy rainfall on the mainland has slowly decreased.
These trends seem to be somewhat at odds with the public's perception of recent years. In fact, the reason why most people are impressed by heavy rain and typhoons is that in addition to the frequency of occurrence, their intensity, duration and scope of impact, as well as the rapid development of mass media and self-media in recent years, are all important factors.
At present, in addition to Typhoon Blavan No. 15, which is turning around and heading towards the heart of the Pacific Ocean, there will be one typhoon in the northwest Pacific in the next 10 days. Even though typhoons may occur in the Northwest Pacific and the South China Sea every month of the year, they are mainly concentrated in summer and autumn, and as the summer winds gradually recede, the typhoon active season will also "come to an end", and it seems impossible to catch up with the annual average typhoon KPI.
Path of Typhoon "Bravan". (Image source: Central Meteorological Observatory)
Looking further, with the normalization of extreme weather, these "ex-standard" typhoons may appear more frequently in the future than in the past. Not only have more super typhoons been generated, but the intensity of typhoons making landfall on the mainland has also shown a trend of strengthening in recent years.
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