Every summer, almost half of China will be affected by the same extreme weather . When we turn on the TV and take out our mobile phones, their strange names will come into our eyes: "Mangosteen", "Tianjin" "Dove", "Durian", "Sangmei", "Haima"...
Although these names are very different, they belong to the same weather system, namely Typhoon .
According to statistics, there are about 15 to 10 typhoons that land in the southeastern river areas of my country every year. Among them, some powerful typhoons will cause huge disasters wherever they go.
Just two weeks ago, this year's No. 9 typhoon "Lekima" (Lekima) was formed in the northwest Pacific Ocean, and then strengthened into super typhoon on August 7, and around the 10th Landed along the coast of Wenling City, Zhejiang Province.
Satellite cloud image when Lekima made landfall on August 10
According to data released by the Central Meteorological Observatory, when "Lekima" landed near the center, the maximum wind force was 16 levels (52 meters/second, super typhoon level), and the lowest air pressure in the center was 930 hPa. The area covered by the moderate and above typhoon disaster risk caused by it has reached .248 million square kilometers.
Shocking scenes when the typhoon made landfall
In the next week, "Lekima" caused a total of 4.024 million people to be affected , 56 people died, 14 people were missing, 15,000 houses collapsed, and 1.137 million crops were affected. hectares, including 93,500 hectares with no harvest, resulting in a direct economic loss of 51.53 billion yuan.
The devastating momentum of the typhoon
According to the assessment of the National Climate Center, "Lekima" is the strongest typhoon to land in my country this year. Its stay on land is the sixth longest since 1949, and its comprehensive wind and rain intensity index is also the longest since 1961. largest since.
The devastating momentum of the typhoon
Its landing affected more than ten provinces (cities) in my country, and the direct economic losses were the second largest since 2000, second only to Typhoon No. 1323 "Fit" (63.14 billion yuan).
Linhai City, Zhejiang Province turned into a land of marshes after the passage of "Lekima"
Someone once said: "When you see a typhoon, it is like seeing Pandora opening her box."
In fact, typhoons are indeed the most terrifying on the earth. The weather system was initially just a small cyclone on the sea, but after a week, the energy it formed was equivalent to ,400 2,000-ton hydrogen bombs .
Satellite cloud image of super typhoon
The disasters it brings to mankind even exceed earthquakes, volcanoes, heavy rains and droughts, ranking first among all natural disasters. How did
this monster that had a huge impact on people's production, life and even customs come into being? How did it enter people's lives from distant oceans?
Today, Mr. DOCO will share with you two documentaries "Deadly Cyclone" and "Wits with Typhoon" . Perhaps from these two films, we will know some secrets about typhoons.
Typhoons were born at sea. Today, with advanced science, people have found the place where typhoons were born, which is called warm pool by meteorologists.
In the warm pool area, strong cumulonimbus clouds will be formed on the sea level after a day of sunlight. The hot air in these cumulonimbus clouds rises, and the surrounding cooler air is continuously replenished, and rises again when heated, and so on. Circulation;
At this time, the air above the entire cloud is hot, and the air below is cold. The evaporation of water vapor in the hot air above expands the scope of the cloud belt. The expansion of the cloud belt makes this movement more violent;
The expanding cloud group is affected by the ground. Affected by the deflection force, it rotates counterclockwise (clockwise in the southern hemisphere), forming tropical cyclone . The centrifugal force generated by the rotating air in the tropical cyclone throws the air outward. The air in the center becomes thinner and thinner, and the air pressure continues to change. Small, tropical depression is formed and is formed - at this time the typhoon appears.
The warm pool is like a womb that breeds life. Typhoons develop and grow here. After growing to a certain size, people can look down on it from space and clearly see its shape.
The seemingly quiet and beautiful vortex structure gives the typhoon the energy to swallow and sweep away everything. The amount of its energy depends entirely on the size of the vortex. In addition, the clearer the eye of the typhoon, the stronger the wind at the center of the typhoon and the stronger the intensity of the typhoon.
After the vortex formed, the typhoon began its long journey. This long journey is not voluntary, it is forbidden.
The movement path of "Lekima"
As it travels, the typhoon will continue to absorb nutrients from the sea water. This is a journey of growth. When it travels a thousand kilometers, it enters its prime. At this time, the typhoon is very energetic and the land is not far away from it.
When "Sangmei" landed in Fujian, reporters conducted on-the-spot reporting. Nearly 140% of typhoons in the world were generated in the northwest Pacific and South China Sea, which is also the coastal areas of China.
Global tropical cyclone path map
However, in the Atlantic coast of the United States and the South Pacific on the South American coast, due to the colder water temperature, there are fewer typhoons generated here, with a total average of less than 0 per year.
Typhoon path map along the coast of China from 1980 to 2005
Over the years, nearly 1/3 of the world’s typhoons have landed in China, and China is also the country with the most typhoons.
However, although meteorologists around the world have done extensive research on typhoons, the latest results show that the deviations in typhoon forecasts have become larger year by year. The danger caused by forecast errors is increasing, and the number of victims may be Up to hundreds of thousands.
Japanese meteorologist
Typhoon "Furong" is a typical example.
This super typhoon hit Japan's Kumejima in October 2016. Just the day before it made landfall, its central pressure was still around 935 hPa, and the Japan Meteorological Agency predicted that the central pressure would not drop again.
But when it passed through waters with higher sea surface temperatures, all predictions were inaccurate. Within 12 hours, its air pressure plummeted to 905 hPa, and the wind speed reached 9.7 meters/second .
As a result, due to inaccurate forecasts, the people of Kume Island were not prepared for the typhoon. The violent storm caused huge losses to the islanders, and the safety of many people's lives and property was greatly endangered.
More serious examples have also occurred in the United States.
In August 2017, Hurricane Harvey hit the southern United States hard. The rainfall of 1,300 millimeters not only set the highest record in the history of the United States, but the raging floods also caused economic losses of 5 billion.
Therefore, on a global scale, countries around the world have begun to improve weather forecasting technology to combat the worsening abnormal weather.
In December 2016, NASA launched eight weather satellites named CYGNSS. They were set to orbit the earth at an altitude of 510 kilometers to measure wind forces near the sea surface around the world.
CYGNSS weather satellite
When the sea surface is calm, GPS satellite signals with almost the same intensity will be reflected back and received by the CYGNSS satellite;
But when the wind increases, such as a typhoon, the sea surface will become rough. At this time, GPS satellite signals will bounce in different directions, and radio waves received by CYGNSS satellites will also weaken.
Scientists can understand and analyze the strength of offshore surface winds based on the intensity of radio waves.
Japanese scientists have also made corresponding progress in directly measuring the movement of clouds inside typhoons.
They have developed a high-performance radar called phase array . When this radar rotates, it can observe the movement of clouds every 30 seconds, and can also observe rapid changes in clouds in three dimensions.
Phased array radar
In August 2016, this type of radar successfully observed the interior of a typhoon for the first time.
When Typhoon "Mintori" hit the Kanto region around Tokyo, Japanese scientists used this phased array radar to synthesize data from images inside the clouds and present minute-by-minute changes in the cloud structure in detail.
Of course, the prediction of typhoons is not something that can be achieved overnight. Perhaps the efforts of these scientists are only minor corrections to the entire prediction work, but quantitative changes will sooner or later lead to qualitative changes, and every correction they make will have an impact on typhoon prevention and disaster reduction work. produce great significance.
When it comes to typhoons, it is estimated that no one will have a favorable impression of it. However, everything has two sides. Typhoons do bring disasters to mankind, but if there were no typhoons, the situation of mankind might be even worse.
Research has found that typhoons have at least the following benefits to humans:
(1) With the surge in global population and the development of industry and agriculture, the demand for fresh water is increasing day by day. In addition, the limited fresh water resources on land are unevenly distributed, and the global Water scarcity has become increasingly serious. Typhoon, a tropical storm, brings abundant rainfall to people.
Typhoons bring a lot of rain to the coast of China, the Sea of Japan, India, Southeast Asia and the southeastern United States, accounting for more than 1/4 of the total precipitation in these areas. It is very important to improve the fresh water supply and ecological environment in these areas. meaning.
(2) Tropical and subtropical areas close to the equator receive the longest sunshine hours and are unbearably dry and hot. If there are no typhoons to dissipate the heat in these areas, it will be hotter and the desertification of the surface will be more serious.
The heat flow brought by the typhoon
At the same time, the frigid zone will become colder and the temperate zone will disappear. Our country will no longer have a spring city like Kunming, nor will there be Guangzhou, which is evergreen all year round, nor "Beidacang", and the grasslands of Inner Mongolia will no longer exist.
(3) The maximum speed of a typhoon can reach more than 200km per hour, causing destruction wherever it goes. This huge energy can directly cause disasters to humans, but it is also thanks to this huge energy flow that the earth maintains thermal balance.
The heat flow brought by typhoons
(4) When a typhoon with huge energy is formed and running, with the help of lightning and other effects, can break long chains of water molecules and form active short-chain water. After the organisms on the earth inhale these short-chain water molecules, they can increase the vitality of life, thereby enabling the sustainable development of the earth's ecology.
Thunder and lightning weather brought by typhoons
(5) Typhoons can turn rivers and seas upside down, rolling up nutrients from the bottom of rivers and seas, increasing the number of fish bait, attracting fish to gather near the water surface, and catches naturally increase.
Fishing boats go fishing after the typhoon
Therefore, we must recognize the fact that in addition to causing trouble, typhoons actually bring a gift to mankind.
Just like Hemingway said: "We must think about how to get along with strange things, see its cruelty, and also see its beauty."
References:
Yang Yaxinxia Jiandong | "Northwestern Pacific Tropical Cyclone Activity" Features》
Hu Dongqi | "Research on the Impact of Typhoons on my country from 1998 to 2017"
