2021-09-14

“Sandu” is coming fiercely: the strong typhoon is the favorite to “haunt” in autumn?

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“Sandu” is coming fiercely: the strong typhoon is the favorite to “haunt” in autumn?

Let’s take a look at some knowledge about autumn typhoons

Autumn, there are still many typhoons!

As for the autumn typhoon, there is no strict definition in meteorology. Generally, typhoons generated from June to August are called summer typhoons, and typhoons generated from September to November are called autumn typhoons.

So far in September this year, there have been 2 typhoons. Statistics show that autumn is still the active season of typhoons. The number of typhoons generated in September is second only to August, and the number of typhoons landed in the whole year ranks third.

“Sandu” is coming fiercely: the strong typhoon is the favorite to “haunt” in autumn?(1)

From 1949 From the big data of typhoons in 2020, it can be seen that in 72 years, in terms of the number of typhoons generated, summer typhoons and autumn typhoons are equal; but in terms of the number of landings, autumn typhoons are obviously less than summer typhoons. This is an average state. In some years, autumn typhoons landed significantly more than summer typhoons. For example, in 2010, 4 typhoons landed in my country in September, while only 2 typhoons landed in the entire summer.

In the 72 years, the most typhoons (9) occurred in September 1966 and 1967, the least (2) typhoons occurred in 1961, and the most typhoons landed in my country in September 2010 (4).

“Sandu” is coming fiercely: the strong typhoon is the favorite to “haunt” in autumn?(2)

Autumn typhoon ratio Xia Taifeng is stronger!

Many people think that the typhoon will be relatively weaker when the weather is cold in autumn, but this is not the case.

Statistics show that among the top 20 typhoons in 72 years, autumn typhoons account for 11, and autumn typhoons are the strongest, and 5 of the top 7 are autumn typhoons.

“Sandu” is coming fiercely: the strong typhoon is the favorite to “haunt” in autumn?(3)

In addition, autumn The average peak intensity and average landing intensity of the typhoon are slightly better than that of the Xia typhoon. It is worth mentioning that the number of super typhoons generated in autumn crushed the summer typhoon with absolute advantage.

“Sandu” is coming fiercely: the strong typhoon is the favorite to “haunt” in autumn?(4)

Then the problem comes Now that it’s getting colder, why can the autumn typhoon become so powerful? The main reason is that most of the autumn typhoons are generated in the Northwest Pacific Ocean, which is far away from the land, giving it enough space and time for development. In addition, the ocean surface has accumulated a lot of heat through the heating effect of the sun throughout the summer. In early autumn, the tropical ocean is heated again as the area of ​​direct sunlight moves southward, making the ocean heat reach its peak, so strong typhoons are more likely to occur at this time.

Compared with summer typhoon, autumn typhoon generally has a longer life history, which is conducive to the development of typhoon intensity. In addition, in autumn, typhoons are less and less affected by the South China Sea monsoon. Although autumn typhoons are generally not too large, the symmetry of the typhoon structure is better and it is easier to develop stronger.

For example, “Sando” was generated on the ocean surface of the Northwest Pacific at 8 o’clock on September 7th. The high sea temperature at low latitudes provided huge energy to the typhoon. “Sando” intensified into a super typhoon at 5 o’clock on the 8th. , It was reduced to a strong typhoon level on the evening of the 12th, and it remained at the super typhoon level for nearly 90 hours. Its structure is also relatively compact, which is conducive to strong development, and finally tied with “Suleki” to become this year’s “Wind King”.

The northernmost landing point of the autumn typhoon is Shanghai

Data shows that in 72 years, the landing point of autumn typhoons that landed in my country was souther than that of the summer typhoon, and the most frequent landfall was Guangdong. , Followed by Hainan and Fujian, the northernmost landing point is Shanghai, the two typhoons that landed in Shanghai are not strong.

The landing point of the autumn typhoon is relatively south, mainly because the subtropical high that affects the path of the typhoon begins to retreat to the south after the autumn, and the path of the typhoon is also adjusted to the south compared to the summer.

“Sandu” is coming fiercely: the strong typhoon is the favorite to “haunt” in autumn?(5)

Since 1949 Only five typhoons landed in Shanghai head-on, which landed in 1949, 1951, 1959, 1977, and 1989, respectively.

The path of autumn typhoons is often complex and changeable. In autumn, the westerly belt system, the subtropical high, the equatorial complex belt and other forces are all in a game state, and sometimes it is difficult to distinguish a clear victory or defeat, so the typhoon movement path and intensity will be more likely to change. There are 3 typhoons listed as “the most complicated typhoon” in history: Typhoon No. 16 in 1986 “Wayne”, Typhoon No. 19 in 1991 “Nat” and Typhoon No. 16 in 2001 “Lily (Nari)”. Among them, “Nite” and “Lily” are autumn typhoons, and the second half of “Wayne”‘s life history is also in late summer and early autumn.

“Sandu” is coming fiercely: the strong typhoon is the favorite to “haunt” in autumn?(6)

It is worth mentioning However, the cold air in autumn becomes active. During the impact of the autumn typhoon, if the cold air cooperates, it may trigger stronger precipitation. In 2013, Typhoon “Fite” landed in Fujian and combined with the cold air going south, bringing a rare and extremely heavy rainstorm to Yuyao, Zhejiang in the northern part of the landing site, which had a great impact.

Regardless of whether “Cantou” is landed or not, people must not take it lightly, pay close attention to the latest local forecasts and warnings, and try not to go out as much as possible.