Why is it rainy in Heilongjiang Province this autumn?

Recently, the weather in the north is mainly rainy. Why is the rain north this year? Counting the "July 21"rainstorm, there were three large-scale precipitation processes in Beijing within 10 days, and the intermittent sound of rain made many people feel that they were in the south. Not only Heilongjiang, but also the northern part of North China, the south-central part of Northeast China and most parts of Southwest China have been shrouded in rain recently.

A set of data provided by Chen Zhenlin, Director of Emergency Disaster Reduction and Public Service Department of China Meteorological Bureau, fully explains how heavy the rain is this year: since the flood season, the national average precipitation has been 232.4 mm, which is 1 1.2% more than the normal period, the highest since 1999.

Among them, the precipitation in the north is obviously more, 42% in North China, 25.9% in Northwest China and 18.4% in Northeast China, and the precipitation in some areas has exceeded the historical extreme. As far as Beijing is concerned, the precipitation since the flood season has reached 368.6 mm, which is 63% more than the same period of the previous year, and it is the year with the highest precipitation since 14.

According to Sun, a senior engineer of the National Climate Center, there are several factors that lead to the rain "favoring" the north this year: the East Asian summer monsoon is strong this year, and the water vapor transport in the north is sufficient; The northeast cold vortex is relatively active,

Under the control of cold vortex activity, the eastern part of northwest China is unstable and prone to precipitation. In addition, this atmospheric circulation situation makes it easier for cold air to go south, and cold and warm weather gathers in the north, resulting in

There is more precipitation.

In fact, from late July to early August every year (commonly known as "seven falls and eight rises") is the main flood season in most parts of the north. Due to the influence of monsoon movement, the rain belt in China advances from south to north. However, this year's precipitation is not only large and long-lasting, but also extreme weather events such as short-term heavy rainfall occur frequently. Sun explained the frequent occurrence of extreme weather from the perspective of climate warming:

First of all, after global warming, the water content in the atmosphere increases, which makes it easy to rain more. According to scientific research, every time the temperature rises by 65438 0 degrees Celsius, the water content can increase by 7%.

Second, climate warming makes the global north-south meridional circulation more active and the atmosphere unstable.

Third, the global regional warming frequency is different, the westerly belt slows down and the circulation continues to strengthen, which provides good dynamic conditions for the occurrence of extreme events.

Compared with the continuous precipitation in the northern region, the areas along the south of the Yangtze River and South China have been under high temperature control recently. However, as Typhoon Sura No.9 and Tropical Storm David No.1 10 approach the coast of China, rain will also become the "weather protagonist" in this area.

According to the forecast of the Central Meteorological Observatory, Sura may land on the coast from Fuqing, Fujian to Yuhuan, Zhejiang from the evening of the 2nd to the morning of the 3rd, and David may land on the coast from Qidong, Jiangsu to Qingdao, Shandong from the evening of the 2nd to the morning of the 3rd. Affected by it, in the next three days, there will be heavy rains in parts of Huanghuai, Jianghuai, Jiangnan and eastern South China, and the local heavy rains can reach 250 to 300 mm.

At present, the Central Meteorological Observatory has continuously issued typhoon orange warning and rainstorm blue warning, and the National Defense General has also launched a Class III emergency response to fully defend against typhoons Sura and Davy.