The impact of cold wave weather on our country
A cold wave is a large-scale cold air activity, so when a cold wave hits, the weather changes dramatically. However, due to differences in seasons, geographical conditions and the intensity of cold waves, weather changes vary from place to place. Generally speaking, the most prominent thing in winter is the drop in temperature and drastic changes in wind direction when a cold front passes through. There are often strong northerly winds behind the front. There are wind and sand phenomena in the northwest and Inner Mongolia. North of the Huaihe River, there is occasional snowfall. Once the cold front passes, the weather becomes clearer. After the cold front passes through the Huaihe River, the chances of precipitation will increase. Especially when the cold front is slow or stationary in the south of the Yangtze River, the precipitation will last for a long time.
Cold wave weather has the greatest impact on agriculture. The cooling brought by cold air can reach 10℃ or even above 20℃, which usually exceeds the cold tolerance of crops, causing frost damage or freezing damage to crops.
The cold-resistant physiological temperatures of different types of crops in different regions also have certain limits. For example, northern spring wheat, beans and oil crops are cold-resistant crops and can withstand low temperatures of -7 to -10°C. Radish can It can withstand low temperatures of -6°C, while cabbage can withstand -4°C, while corn and potatoes can only withstand -3 to -2°C. Moreover, various plants have different cold tolerance at different stages of growth and development. For most plants, they will be significantly damaged when the temperature drops to around 0°C. Almost every cold wave in history has caused widespread crop damage, and the extent of the disaster varies greatly depending on the scope of the cold air invasion.
After the cold wave passes, the temperature drops suddenly, and the cooling can last from one to several days. The northwest and north China regions have a large cooling rate, while the central and southern regions have a smaller cooling rate, but freezing and frost can occur. For example, in January 1955, due to the continuous and explosive cold waves moving southward, temperatures reached -14.6°C in Wuhan, -19.2°C in Shanghai, extreme minimum temperatures of -2.1°C in Nanning, and rare frosts occurred in Hainan Island. Among them, many areas in Jiangsu, Anhui, Hubei, Hunan, and Jiangxi provinces experienced heavy snowfall and freezing rain for 10 to 15 consecutive days, causing transportation and telecommunications to be blocked, and agricultural and animal husbandry production to suffer heavy losses. In spring and autumn, in addition to strong winds and cooling, cold wave weather often brings rain and snow south of the Yangtze River Basin. Disastrous weather such as thunderstorms and hail sometimes occurs, especially the final frost, first frost and frost caused by cold waves, which pose a greater threat to crops in North and Central China, often causing severe yield reductions.
Cold waves and strong cold air usually bring strong winds, cooling, rain, snow and freezing weather, which are the main disastrous weather in my country in the winter half.
Strong winds can cause trains to derail or even overturn. In my country, strong winds overturned trains, which happened in many places in Xinjiang. The Lanzhou-Xinjiang Railway passes through the "100-mile wind zone" near Hami and the "30-mile wind zone" in the Dabancheng area of Tianshan Mountains. From 1961 to 1982, strong winds overturned trains 10 times. During strong wind seasons, trains often fail to run on time.
The impact of strong winds on civil aviation is also very significant. Wherever the cold air reaches, the average wind speed is generally above 15m/s, and the gusts are above 25m/s, and lasts for a long time. Strong winds make takeoff and landing difficult. Aircraft are prone to accidents such as tire rupture and landing gear breakage.
Rain will also threaten the flight safety of the aircraft. When the aircraft flies in clouds with supercooled water droplets, water will accumulate on the wings and propellers, affecting the aerodynamic performance of the aircraft and causing a crash.
Therefore, for the safety of winter flights, modern aircraft are basically equipped with de-icing equipment. When smog forms on the road, highway traffic is blocked due to ice on the ground, and traffic accidents increase. Ice accumulation on mountainous roads is also very dangerous, often causing cars to slide toward cliffs.
The arrival of the cold wave will not only cause strong winds and cooling weather, but also cause rain and snow weather at the junction of cold and warm air. The rain and snow weather itself will have a great impact on roads, railways and people's travel. In addition, the cooling brought by the arrival of the cold wave will make the temperature lower, which is not conducive to the melting of snow. Freezing will still occur in some areas, which will have an adverse impact on transportation. If the cold wave weather lasts for a long time, it will further increase the thickness of the ice on the road, which will in turn cause the highway to be forced to close, resulting in an increase in the number of passengers stranded; this will further increase the transportation pressure on the railway. The thickening of road ice will likely increase more traffic accidents and bring more safety risks. If the damage to the power grid further intensifies, it may endanger the railway power grid again, thus affecting the normal operation of trains. Continued icy weather will again cause flight delays.