Experts from the Central Meteorological Observatory interpreted the causes of heavy precipitation in Sichuan, Yunnan and other places and the impact of tropical depression
On August 16, heavy rains occurred in the central and western parts of the Sichuan Basin, southern Sichuan, southeastern Gansu, central Shanxi, eastern Yunnan, and central and southern Guangxi. Among them, Chengdu and Deyang, Sichuan were particularly torrential rains. The Central Meteorological Observatory continued to issue an orange rainstorm warning at 6 o'clock on August 17th: precipitation is expected to continue from 17th to 18th.
What is the extent and intensity of the precipitation this time? What is the cause of continuous heavy precipitation in Sichuan, how long will it last, and which basins will the future precipitation affect? In addition, will the newly generated tropical depression affect our country? In response to these issues, the reporter interviewed Sun Jun, chief forecaster of the Central Meteorological Observatory, and Nie Gaozhen, senior engineer of the Typhoon and Marine Meteorological Forecast Center of the China Meteorological Administration.
Guest: Sun Jun, Chief Forecaster of the Central Meteorological Observatory
Nie Gaozhen, Senior Engineer, Typhoon and Marine Meteorological Forecast Center, China Meteorological Administration
Reporter: China Meteorological News reporter Zhang Hongwei Xinhuanet reporter Hao Duo
Reporter: As of now (August 17), what is the actual rainfall situation in Sichuan, Gansu and other places? Which places have broken through historical extremes? How was the previous precipitation in the Northwest China?
Sun Jun: On August 16, heavy rains occurred in the central and western Sichuan Basin, southern Sichuan, southeastern Gansu, central Shanxi, eastern Yunnan, and central and southern Guangxi. Particularly heavy rains (250 mm to 414 mm) occurred in Chengdu and Deyang, Sichuan. The maximum precipitation occurred in Chengdu Shuangliu (415 mm), and the maximum hourly precipitation was 92 mm.
Since August 10, the cumulative rainfall in the central and western parts of the Sichuan Basin has generally exceeded 250 millimeters, 400 to 600 millimeters in some areas, and 1,000 to 1197 millimeters in Deyang and Mianyang. The daily rainfall of 14 counties and cities including Lushan, Shifang, and Chongzhou in Sichuan exceeded the extreme value of the same period, and 9 counties and cities exceeded the historical extreme value. The eastern part of the northwestern region had more early precipitation. The central and eastern Gansu, the southern Ningxia, and the central and southern Shaanxi showed precipitation of 40 to 90 mm, and some areas showed precipitation of more than 100 mm.
Reporter: What is the scope and intensity of this round of precipitation? Is the heavy rainfall in the Sichuan Basin consistent with the previous impact system? How will the precipitation situation develop?
Sun Jun: From the 17th to the 18th, a rain belt from northeast to southwest will affect our country. Affected by the precipitation center of the rainband, parts of the Sichuan Basin, the Western Sichuan Plateau, Yunnan and other places have heavy to heavy rains. Among them, the central and western parts of the Sichuan Basin have heavy or extremely heavy rains.
On the 17th, there were heavy to heavy rains and local heavy rains in northeastern Inner Mongolia and northwest Heilongjiang; from the 17th to 20th, there were moderate to heavy rains, local heavy rains or heavy rains in eastern Northwest China, North China, and central and southern Northeast China. The above areas are accompanied by strong convective weather such as short-term heavy rainfall, thunderstorms, gales or hail.
The combination of the southwest vortex and cold air is the main cause of continuous heavy rainfall in the Sichuan Basin. From day to night on the 17th, the rainstorm areas were concentrated in the central and western Sichuan Basin and the southern part of the western Sichuan Plateau. There were heavy rainstorms in the above-mentioned local areas. The local rainfall in the western Sichuan Basin could reach the extreme heavy rainstorm level (250 to 300 mm); As the main rain belt moved eastward, the rainfall in the Sichuan Basin and the eastern part of the northwestern region gradually weakened.
Reporter: How about the precipitation in the next ten days? Which river basins need to be focused on?
Sun Jun: From August 17th to 26th, the main rainfall areas were located in the eastern part of Northwest China, most of North China, Northeast China, northern Huanghuai, South China, and eastern Southwest China. The cumulative rainfall is generally 40 to 80 mm. Among them, the southeast of North China 100 to 200 mm in parts of the western Sichuan Basin, southern Northeast China, northeastern Huanghuai, western Sichuan Basin, central and southern South China, and parts of Yunnan and southern Shaanxi; local areas in the western Sichuan Basin and southern China can reach more than 250 mm; most of the above areas The accumulated rainfall is 50% to 1 times more than that of the same period in normal years, and more than 2 times more locally. The above-mentioned areas need to guard against disasters such as mountain torrents, landslides, mudslides, and urban and rural waterlogging that may be caused by heavy rainfall. Especially in the central and western parts of the Sichuan Basin, the accumulated rainfall is large and lasts for a long time, and the meteorological disaster risks of mountain torrents, geological disasters and floods in small and medium rivers High, need to strengthen prevention.
It is necessary to focus on precipitation in the upper reaches of the Yangtze River, the middle and lower reaches of the Yellow River, the Haihe River, the Liaohe River, and the Pearl River.
Reporter: How will the tropical depression in the northeastern Philippines develop in the later period? Will it affect my country?
Nie Gaozhen: On the afternoon of August 16, a tropical depression formed in the northeastern part of the Philippines. It will develop into the seventh typhoon this year and the fifth typhoon since August this year.
It is expected that the tropical depression will move to the northeastern part of the South China Sea this evening, and then gradually increase in intensity. It will develop into the No. 7 typhoon this year on the 18th, and then gradually approach the coast from western Guangdong to the northeastern part of Hainan, and will be in the early morning of the 20th. Landing on the aforementioned coast in the morning (28-33 m/s, 10-12 level, severe tropical storm level or typhoon level).
As the current atmospheric and marine environmental fields are still being adjusted, there is a possibility of strengthening offshore after the typhoon is generated. All localities and relevant departments need to pay attention to the latest forecast and warning information in a timely manner and take precautions.