Why has drought appeared in many places this year? Experts say the drought may continue
In recent times, high temperatures have occurred across most of northern China, further intensifying soil moisture evaporation and causing the drought to spread rapidly across various regions. Meteorological experts believe that in summer, it is fairly common for some parts of China to experience either drought or flooding. At present, the main grain-producing areas have not formed large-scale drought, but grain output in some local areas with more severe drought has been greatly affected
As an agricultural proverb goes, “Drought or flood is determined on the 15th day of the seventh lunar month, and the harvest is determined on the 15th day of the eighth lunar month.” Currently, China's autumn grain is at an important stage of growth and development, yet with the high-temperature and low-rainfall weather that has appeared across most areas north of the Yangtze River since the start of summer, severe drought has occurred in many places.
Meteorological monitoring data show that since July, precipitation in North China, the Huang-Huai region and the southeastern part of the Northwest region has been significantly more than 50 percent below normal, and in some parts of central Henan, precipitation has been even more than 80 percent below normal, the lowest for the same period since 1961.
Why is the north, which has entered the main flood season, now experiencing large-scale drought? “The low precipitation is mainly affected by a relatively strong continental high.” Zhang Tao, chief forecaster of the National Meteorological Center, explained that at present most of northern China is under the control of the western Pacific subtropical high, causing persistent clear, hot and rainless weather in the north, especially in North China and the Huang-Huai region.
The subtropical high refers to a warm high-pressure system located in the subtropical region, and is one of the main weather systems affecting the weather over mainland China in summer and causing summer drought and flood changes. Within the subtropical high area, the weather is generally clear, and when it controls a certain region for a long time, it often causes high temperatures and drought in that region.
“In addition, in recent times, high temperatures have occurred across most of northern China, further intensifying soil moisture evaporation, so the drought has spread rapidly across various regions.” Zhang Tao said.
Fortunately, the drought in some of the above areas has now eased slightly. According to the National Meteorological Center, from July 29 to August 1, significant rainfall has occurred (or will occur) in Shanxi, Hebei, Shandong, Sichuan and other places.
“The rainfall is concentrated in North China and the Huang-Huai region, where precipitation was below normal earlier, which is very favorable for alleviating the local drought.” Mao Liuxi, a researcher at the National Meteorological Center, told reporters that the drought in northwestern Anhui has basically eased, and the drought in central and eastern Henan has been greatly alleviated.
Mao Liuxi introduced that according to the latest monitoring, judging from the national soil moisture conditions, the drought in central and western Henan and the Guanzhong region of Shaanxi is still continuing or spreading; signs of drought are emerging in the eastern Sichuan Basin, central Hebei, central Inner Mongolia and Hubei, and if there is no precipitation later, the drought will develop quickly.
Zhang Tao told the Economic Daily reporter that in the next 10 days, apart from strong rainfall along the eastern coast affected by typhoons, no large-scale strong rain belt will appear nationwide, while some local areas in North China will have 2 small-scale rainfall processes, but the rainfall will be relatively light, and the affected areas will also be limited to central and northern Hebei, eastern Inner Mongolia and areas toward the south.
In addition, according to meteorological forecasts, temperatures in most parts of the country in August will be close to or above the same period of normal years. “By then, the drought in North China, the Huang-Huai region and other places may continue or develop, and a summer drought is very likely to occur.” Mao Liuxi suggested that places with the conditions should carry out artificial rain enhancement or agricultural irrigation in a timely manner, meteorological departments should do a good job in weather forecasting, and agricultural departments should intensify monitoring and assessment, promptly grasp the development and changes of the drought, and take multiple measures to increase water sources for drought resistance.
However, at present, there may be no need to worry excessively about the autumn grain issue. “This year's drought is not very severe compared with the same period in history.” Mao Liuxi said that in summer, China's precipitation distribution is usually uneven, and overall it is fairly common for some areas to experience either drought or flooding. At present, the main grain-producing areas, such as the Northeast and Hunan, have not formed large-scale drought, but grain output in some local areas with more severe drought has been greatly affected.