Since Typhoon No. 11 "Capricorn" landed in South China on September 6 and severely damaged South China, our country has ushered in a long and intensive month of typhoon landings. Typhoon No. 13 "Bebigat" has just retreated, and Typhoon No. 14 "Plasang" will arrive at super speed. There are also Typhoon No. 15 "Suli" and Typhoon No. 16 "Cimalon" waiting in line. Heavy rains at all levels are expected. One after another, sweeping the earth.
How did the typhoon form? Why are typhoons coming one after another before National Day this year? How can we rely on existing technology to predict typhoons and protect people's personal and property safety during storms? The Paper invites well-known science blogger and top 100 up blogger Zhongqiai (@中国 Weatherlovers) to talk about the causes of typhoons and extreme climate.
Click on the picture to ask a question
Why are there so many typhoons this autumn?
@ Monkey King: The forecast route of Typhoon No. 14 "Plasang" basically coincides with that of "Bebiga". Will it cause a double blow to the coastal areas of East China? "Capricorn" has just left, why are there so many typhoons recently?
中气爱: The route of Typhoon "Plasang" is slightly southerly than that of "Bebiga", and it is expected to land in Zhejiang, which can be said to be a double hit on the East China coast. In September this year, typhoons generate and make landfall more frequently. The number of typhoons generated may reach 6, of which at least 3 will make landfall in my country and affect more than 4 people. The main reasons are:
1. The subtropical high pressure moved northward in September this year, leaving the tropical ocean surface and typhoons having room for development;
2.mjo The rising wave is in the Indo-Pacific region, which is conducive to the development of tropical convection in the northwest Pacific;
3. The northwest Pacific Sea temperatures in most parts of the South China Sea and the South China Sea are significantly higher, providing sufficient energy support for the development of typhoons;
4. This year is El Niño turning to La Niña, which is conducive to the development and landing of typhoons offshore my country.
@阿飞negative传: Why was Beibijia able to break the "Magic City Barrier" this time?
中气爱: Although the "Magic City Barrier" is a joking name, it also reflects the reality that it is not easy for typhoons to land directly in Shanghai. Why is it difficult for typhoons to land in Shanghai? Because Shanghai has a high latitude and the sea temperature is low and the air is dry in the northern part of the East China Sea, it is difficult for typhoons to directly turn west at this latitude, and it is also difficult for typhoons to directly hit the coast of Shanghai, which has a relatively short coastline.
"Bebigia" was able to land this time because, first, the subtropical high in mid-September was abnormally northerly and strong, which guided "Bebigia" to the northern part of the East China Sea, turning east-west in Shanghai; second, the water temperature in the northern part of the East China Sea was abnormal It's on the high side, almost always above 30 degrees, allowing "Bebiga" to maintain intensity or even strengthen, maintaining its peak state for landing.
@praising nothingness: I read news reports that Typhoon Bebigat landed during the astronomical tide period. What risks does this pose to coastal areas?
中气爱: will increase the risk and harm of storm surges, and preparations should be made to prevent moisture and support.
@paperbagrose: I saw that Typhoon Bebigat could affect Inner Mongolia, Qinghai and other places. Is this true?
Middle air love: The main circulation of "Beibijia" affects Shanghai, Jiangsu, Zhejiang, Anhui, Henan, and Shandong. Its peripheral airflow combines with the subtropical high easterly wind to transport water vapor to Shaanxi, Gansu, Ningxia, Qinghai, and Inner Mongolia. Waiting places.
Typhoon "Plasang" path. Screenshot of the Central Meteorological Observatory·Typhoon Network
The formation and prediction of typhoons
@水瓜COLAWEI: How do typhoons form?
中气爱: Typhoons form in warm tropical or subtropical oceans. At present, it seems that there are three necessary conditions for the generation of most typhoons: 1. The sea surface water temperature is above 26.5 degrees; 2. It is some distance from the equator; 3. There is Sufficient water vapor replenishment. In the formation mechanism of typhoons, the occurrence, development and initial disturbance of cumulus convection are both important.
@Nian Datang: When do typhoons usually land in my country in a year? How strong will the first typhoon be?
中气爱: From a climatic perspective, typhoons have landed in my country in all seasons of spring, summer, autumn and winter, mainly in summer and autumn.On average, the first typhoon landing in my country occurs in mid-to-late June, and is usually a tropical storm or severe tropical storm. The earliest typhoon made landfall was in April, and the first and strongest one was a severe typhoon.
@puzzKang: What technology does my country rely on to predict the intensity and path of typhoons?
中气爱: At present, the determination of the intensity of typhoons in the open sea mainly relies on satellite cloud image intensity determination technology, actual measurements of ships, actual measurements of outlying islands and sporadic aircraft detection; in addition to the above methods, intensive ground observations and radars are also used to determine the intensity of offshore typhoons. Observation and so on. The typhoon path mainly relies on numerical models and artificial intelligence models.
@Ruyingsuixing1999: I am from Hebei. I am curious, why have I never seen a typhoon land in Hebei? I have seen people land in the Northeast.
中气爱: The coastline of Hebei is in the Bohai Bay. To land, the typhoon needs to turn west at 40 degrees north latitude and avoid Tianjin. This is almost impossible, so there has been no typhoon landing in Hebei so far. You can do it by traveling to the northeast of Liaoning, so there are quite a few typhoons that land in Liaoning.
@I can’t understand the code no matter how hard I type it: Are typhoons and tornadoes comparable? Which one is more powerful?
Medium Air Love: Typhoons are relatively barotropic cyclones on a synoptic scale, with diameters ranging from hundreds to thousands of kilometers, and are very large; tornadoes are medium- and small-scale cyclones that occur in strong baroclinic environments, with diameters of only tens of meters to one meter. km. In terms of maximum wind speed, strong tornadoes are larger; but in terms of total energy, typhoons are much larger than tornadoes. In fact, tornadoes will also appear in the spiral rainbands of typhoons. For example, the spiral rainbands of "Bebiga" that just landed have triggered multiple tornadoes in Jiangsu, Anhui and other places.
How accurate can the weather forecast be?
@I thought I would get rich: How accurate is the weather forecast today?
中气爱: The accuracy of weather forecast depends on how it is measured. The measurement method of each factor is different. For example, for typhoons, the 24-hour path error rate has been reduced by 50% in more than ten years; for example, for temperature forecasts, the 24-hour forecast can already be within plus or minus 2 degrees. Generally speaking, the forecast accuracy is definitely improving; but at the same time, people's requirements are also increasing, so there will often be a situation where the improvement in forecast accuracy cannot keep up with the improvement in people's requirements, so satisfaction may not necessarily improve. rise.
@小Rabbit: Excuse me, what standard is usually used to calculate the "once-in-a-century" in weather forecasts?
中气爱: "Once in a hundred years" is a concept of probability and statistics. It means that based on calculation, an event in a long-term sequence will occur once in a hundred years on average. It has many premises, and it does not mean that it occurs once in a hundred years. It must happen once a year. The forecast generally does not mention the once-in-a-century event, but whether it is extreme, whether it breaks through the extreme value, etc.
