Heilongjiang Meteorological Observatory
Recently, the flood situation in Heilongjiang has attracted much attention. On June 24, Chen Lijuan, chief forecaster of the National Climate Center and chief engineer of the Climate Prediction Office, introduced to The Paper (www.thepaper.cn) that the precipitation in Heilongjiang was abnormally high in June this year, which was significantly more active and intensified than the Northeast Cold Vortex. Stronger is closely related, and according to the diagnostic analysis of the ocean, land surface and other external forcing signals and atmospheric circulation evolution characteristics, the East Asian summer monsoon is expected to be stronger this year, especially from late July to early August (abbreviated as “seven ups and eight downs.” ) In the north, it is more likely that there will be a concentrated period of heavy rainfall.
According to statistics from the Heilongjiang Meteorological Observatory, the precipitation at the Nenjiang station this year has been basically the same as in 1998. Zhao Guangna, deputy director of the Heilongjiang Meteorological Observatory, said that it is expected that in Heilongjiang Province in the last few days will be mainly scattered precipitation, and there will be no systematic heavy precipitation for the time being. “At present, the flood peak is in the Daxingan Mountains and will flow eastward along Heilongjiang. Considering the water flow speed, if the flood peak overlaps with the rain belt during the main flood season, there will be greater flood control pressure, so the weather service task is very heavy.”
Monitoring shows that the total area of river water bodies in Daxinganling area has expanded by 1,366 square kilometers
According to Chen Lijuan, rainfall in the northeast flood season can be divided into two stages, early summer and midsummer, according to the difference in the impact system. Among them, the precipitation anomalies in the late spring and early summer (May and June) were mainly affected by the northeast cold vortex and the Okhotsk obstruction high pressure. The precipitation anomalies in July and August were mainly affected by the second northward jump of the western Pacific subtropical high. influences.
“At present, the abnormally high precipitation in Heilongjiang is closely related to the obvious activity and stronger intensity of the Northeast Cold Vortex than usual.” Chen Lijuan said.
Forecast map of total precipitation in the basin from June 23 to 30, 2021. Source: Heilongjiang Meteorological Observatory
Meteorological monitoring data show that since April (until June 19), cumulative precipitation in Heilongjiang and eastern Inner Mongolia has generally reached 100 mm to 230 mm, and the local area in northwest Heilongjiang and northeastern Inner Mongolia has reached 250 mm to 304 mm. The precipitation in western Heilongjiang and northeastern Inner Mongolia is 50% to 2 times more than the historical period.
Among them, the Daxinganling region, which is closely related to the water volume of Heilongjiang and the main stream of the Nenjiang River, has an average precipitation of 246.4 mm since April, which is 1.3 times more than the same period in history (108.2 mm).
The severe flood conditions in Northeast China this year are also related to the heavy snowfall in the previous winter. Zhao Guangna said that from November 1 last year to June 21 this year, the total precipitation at the main stations in the Heilongjiang River Basin exceeded the historical period by about 40%. “Since November last year, there has been a lot of snowfall in the Greater Khingan Mountains in winter, and the melting of snow has caused more river flow.”
If the flood peak overlaps with the rain belt in the later main flood season, it will increase the pressure on flood control
According to the monitoring of the Northeast Satellite Meteorological Data Center and the Heilongjiang Ecological Meteorological Center, the water bodies of many rivers in the Greater Xing’an Mountains area have significantly expanded compared with the same period last year. On June 21, 2021, compared with June 30, 2020, the total area has increased by 1,366 square kilometers. .
Up to now, the precipitation at the Nenjiang station has been basically the same as in 1998. However, according to weather forecasts, from June 22 to 28, the cumulative rainfall in Heilongjiang and northeastern Inner Mongolia will be 2 mm to 15 mm, and the northern part of Heilongjiang will exceed 20 mm; Russia’s Jieya River, Bureya River and the lower reaches of Heilongjiang The rainfall is 15 mm to 40 mm. In addition, according to the climate forecast issued by the Heilongjiang Provincial Climate Center, Heilongjiang Province has slightly more precipitation in summer this year, and the midsummer (July to August) is normal.
Hu Jianwei, chief hydrological forecaster of the Ministry of Water Resources, previously judged in an interview with The Paper that the floods in Heilongjiang will take at least one month to recede. In this regard, Zhao Guangna said that the current flood peak is in the Daxingan Mountains and will flow eastward along Heilongjiang. Taking into account the water flow speed, “if it overlaps with the rain belt in the later main flood season, there will be greater flood control pressure, so the meteorological service task is very heavy. .”
Zhao Guangna said that at present, the meteorological department is making every effort to do a good job of forecasting precipitation, including organizing in-depth scientific research on the reasons for the strong cold vortex and long active time this year, and rolling out the area rainfall forecast and forecasting of the basin. At the same time, in view of overseas weather and climate trends, the meteorological department exchanges site monitoring data, uses satellite data to produce quantitative precipitation inversion products and related business platforms, grasps the actual precipitation in the Far East in real time, and uses numerical weather forecast models and dynamic climate models to conduct overseas weather. Forecast and climate prediction provide decision-making support for flood prevention and mitigation and post-disaster reconstruction.