Original title: Heavy rains in South China are like watching the driving force behind it South China SeaHow the summer monsoon drives the progress of my country's rainy season
Time has entered the Beginning of Summer solar term, heavy rains, high temperatures, and strong convection have begun to appear sporadically, and a hint of summer can also be smelled in northern my country. Taste it. But I always feel it’s still a little bit short. In fact, at this time, spring still occupies a large area of our country, and summer is still waiting, waiting for the monsoon from the tropical ocean to blow summer rain and warmth all over the country... The "South China Sea Summer Monsoon", the driving force behind my country's rainy season, is already gaining momentum. Fa, coming soon.
Heavy rains are coming in South China. The driving force behind the "South China Sea Summer Monsoon" appears
html On May 12, Guangzhou citizens were waiting for heavy rains. The short-term heavy rainfall caused flooding in some streets. Not only Guangzhou, but also the whole province of Guangdong, Guangxi, Fujian and other places entered the crazy water-splashing mode from the 11th. The cumulative rainfall in many places exceeded 300 mm. Zhuhai, Shenzhen, Zhongshan , Nanning and other places have sounded the highest warning. Level red rainstorm warning. This rainfall process has the characteristics of long duration, large cumulative rainfall, and strong rainfall at a single point. It is the strongest rainfall process in the south since the flood season this year.
my country's Fengyun 4A meteorological satellite monitors water vapor channels. Water vapor is obvious in the Pearl River Estuary of Guangdong and eastern Guangdong. (Monitoring on May 13, National Satellite Meteorological Center )
The rainfall process currently experienced in the south is the masterpiece of the South China Sea summer monsoon. The warm and moist airflow from the southwest sea continuously delivers a large amount of water vapor. Arriving in southern my country, coupled with the intersection of cold and warm air, heavy rainfall is triggered. After this round of heavy rainfall, the South China Sea summer monsoon, the driving force behind my country's flood season, appeared.
The National Climate Center issued an article on May 9, saying that predictions of the East Asian summer monsoon circulation indicate that the 2022 South China Sea summer monsoon will break out in the third pentad of May, that is, from May 11th to 15th. The fourth phase of May is slightly earlier than normal, and the intensity is close to normal to weaker.
The South China Sea summer monsoon joins forces with the subtropical high to promote my country’s rainy season process
After the South China Sea summer monsoon comes on stage, the subtropical high gradually moves northward. During the flood season, with the cooperation of the water vapor brought by the monsoon and the advance and retreat of the subtropical high, my country's main rain belt advances from south to north.
It enters April all year round. The pre-flood season in South China will take the lead in kicking off the flood season in my country, but it will have to wait until early June for the rainy season to begin on a large scale. At this time, the South China Sea summer monsoon has broken out, bringing a hurricane to South China along the periphery of the subtropical high. Another rain. During the Dragon Boat Festival, the dragon boat race, which is popular among people in South China, is in full swing. The rainfall during this period is also called "dragon boat racing".
In mid or late June, the subtropical high pressure moves northward for the first time, and the rain belt also moves northward to the Yangtze River Basin, and the famous Jianghuai Meiyu begins.
In 2020, the middle and lower reaches of the Yangtze River encountered "violent plumes", Wuhan river beaches were flooded, and the "pavilions" became "cool". (Photo/Li Bichun)
Around mid-July, the subtropical high pressure ridge line moved northward for the second time. The Meiyu period in the middle and lower reaches of the Yangtze River ended, and the "baton" of the rain belt was transferred to the Huanghuai region.
From the end of July to the beginning of August, the subtropical high pressure moved northward for the third time, and North China and Northeast China entered the rainy season of "seven falls and eight rises".
In addition to affecting the process of my country's main rain belt, the strength of the South China Sea summer monsoon also affects the total precipitation in different regions during the flood season in my country. Data show that the South China Sea summer monsoon intensity index has a significant inverse relationship with summer precipitation in the middle and lower reaches of the Yangtze River and the Huaihe River basin, and has a significant positive correlation with precipitation in the Jiangnan region and post-flood season precipitation in South China.
The reason for this is also the result of the game between the South China Sea summer monsoon and the western Pacific subtropical high . Li Liang, a meteorological analyst at China Weather Network , said that in strong South China Sea summer monsoon years, the intensity of the subtropical high pressure is weaker than in normal years, the position of the ridge is northerly, and the maximum peak flow in the middle and lower reaches of the Yangtze River and the Huaihe River Basin during the flood season is smaller; In a weak South China Sea summer monsoon year, the intensity of the subtropical high is stronger, the ridge is located farther south, and the maximum peak flow in the middle and lower reaches of the Yangtze River and the Huaihe River Basin during the flood season is larger, resulting in a higher frequency of flood disasters.
In the summer of 2007, the Huaihe River Basin experienced a major flood second only to that of 1954. Many large cities and regions were hit by rare heavy rains, causing serious disasters. The study found that the South China Sea summer monsoon in 2007 broke out late and was weak in intensity, while the subtropical high was strong and located southward. Water vapor was transported by southerly winds on the west side of the subtropical high and continuously reached the Huaihe area, providing heavy rainfall in the Huaihe River. Abundant water vapor conditions and continuous heavy rainfall caused floods in the Huaihe River.
In late spring and early summer, the wind rises from the south of the sea
In order to understand how the South China Sea summer monsoon exerts its magical power to control wind and rain, we must first start with the meteorology concept of monsoon. The essence of the monsoon is a large-scale wind between the continent and the ocean, whose wind direction changes regularly with the seasons due to the thermal difference between the sea and the land. It is a phenomenon in which the prevailing wind directions are opposite in the winter and summer seasons on a large scale with a one-year cycle.
Asia is a world-famous monsoon activity area, and my country is one of the countries with the most significant monsoon climate in the world. The Asian monsoon includes the South Asian monsoon and the East Asian monsoon. The South Asian monsoon affects South Asian countries such as India and Bangladesh. The monsoon that affects our country is mainly the East Asian monsoon, and the South China Sea summer monsoon is an important part of the East Asian summer monsoon.
Every year in early May, the Asian summer monsoon begins to move near the Bay of Bengal . By mid-May, a large amount of water vapor enters the South my country Sea, where it continues to increase in temperature and water, and eventually carries a large amount of water vapor and heat towards the coast of South my country. The South China Sea summer monsoon breaks out.
Li Liang explained that the outbreak of the summer monsoon in the South China Sea means that water vapor has opened up the "Ren and Du Meridians". The water vapor channel from the Indian Ocean through the Indian Peninsula , the Bay of Bengal, the Indo-China Peninsula and the South China Sea to the central and eastern regions of my country has been fully opened. The water vapor transport in the southwest has been significantly enhanced. In conjunction with the cold air activity in the north, it is easy to cause high intensity and wide range in the southern region of my country. , Long-lasting heavy precipitation events are increasing, and severe convective weather is frequent.
The outbreak of the South China Sea summer monsoon will change the heat and moisture balance in the entire Asian region. It is a major turning point in the climate seasonal transition in Asia. It also means that my country will fully enter the main flood season.
Speaking of this, have you finally felt the importance of the South China Sea summer monsoon, a wind blowing from the distant sea, to our lives? At present, the South China Sea summer monsoon is gaining momentum, and the rainy season in the new year is about to begin in full swing. Flood prevention work cannot be relaxed. (Planning: Feng Wei Data support: Li Liang Design: Chen Yujie)
Source: China Weather Network
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