China Meteorological News reporter Liu Zhao
From Mohe at the northernmost point to Zengmu shoal at the southernmost point, China territory spans nearly 50 degrees latitude from north to south, with a distance of about 5,500 kilometers. According to the difference of main meteorological elements, China is divided into 11 first-class meteorological geographical regions by opening the Handbook of Meteorological Geographical Zoning in China. In winter, the climate difference between these areas is further amplified, forming a unique climate landscape.
Cold is the most distinctive label in winter in Northeast China. Mohe County, located in the northernmost part of China and adjacent to Russia, is called the cold pole of our country. It is normal here that the earth is covered with snow. According to Wu Shusen, an engineer from the Meteorological Bureau of Mohe County, Heilongjiang Province, it snows every year from around October 15th, and the snow with a depth of more than 10cm will last until mid-April of the following year. On June 4th, 1992, "Six In the snow" appeared in Mohe, which was the latest snowfall date since Mohe had meteorological records. Generally, October 3rd is the start date of continuous freezing in Mohe River, and it ends on May 11th of the following year, with an average of 220 days of continuous freezing. The average temperature in Mohe County in January is -30.9℃. On February 13th, 1969, the low temperature of -52.3℃ appeared here, which was the extreme lowest temperature in the existing meteorological data of China.
The yellow river is frozen
For many provinces in the Yellow River Basin, the freezing of the Yellow River is a major event in winter. "Up and down the river, the sudden loss of surging" describes the spectacular scene of the Yellow River freezing in winter.
To some extent, the morning and evening of the Yellow River freezing and the length of freezing are indicators of the climate of that year. In the winter of 2014-2015, the cumulative maximum frozen length of the main stream of the Yellow River reached 707 kilometers. Among them, the upper reaches are frozen for 650 kilometers, the middle reaches are frozen for 57 kilometers, and the lower reaches are not closed. In the winter of 2002-2003, due to frequent cold air, the temperature in the basin was low. The total length of the Yellow River was 1121 kilometers, and the frozen area was as far away as Heze, Shandong.
When winter goes and spring comes, when the Yellow River is unblocked, because of its different geographical location and latitude, especially the two sections from Lanzhou to Hekou Town, Inner Mongolia, and from Huayuankou, Zhengzhou to the estuary, the flow direction is from low latitude to high latitude. When the upstream river melts, the downstream is often frozen, and a large amount of ice and water in the upstream flow downstream, forming a large ice flood peak, which is easy to get stuck in the curved and narrow sections and dam up.
Dry season of Yangtze River
The sandbar in the middle of the river is almost connected with the shore, and it looks like a grassland at close range; The river beach is exposed in a large area, exposing stones and silt; Some river sections are exposed to the bottom of the river, and the soil on the surface is cracked … This is a common sight in the dry season of the Yangtze River in winter.
The dry season is a major challenge faced by 11 provinces in the Yangtze River Basin every year. The amount of low water flow and the length of low water period have great influence on irrigation, power generation, shipping, industry and urban water supply in the Yangtze River basin. Since November 7, 2015, the discharge of Gezhouba has been less than 8000 cubic meters per second for three consecutive days. On November 9, the discharge flow was only 6800 cubic meters per second, and the local water level in Yichang, Hubei Province fell below 1 meter, which was only 0.74 meters, marking that the middle reaches of the Yangtze River entered a dry season in an all-round way. On the same day, traffic control began in key shallow areas in the middle reaches of the Yangtze River.
Nowadays, under the background of climate change, the change of precipitation in the upper reaches, the reduction of snow on the Qinghai-Tibet Plateau and the increase of water consumption in cities along the Yangtze River make the challenge of dry season more severe.
Plateau warm sun
Winter on the Qinghai-Tibet Plateau often leaves people with the impression of cold, heavy snow and lack of oxygen. Therefore, many people are discouraged from Tibet in winter. In fact, looking up the climate data, we can find that winter is the most suitable season to enjoy the sunshine in Tibet.
Take Lhasa as an example. Winter here is not as cold as expected, and snow is rare. The probability of sunny days is more than other seasons. Tibet is a place with a large daily temperature difference but a small annual temperature difference. The climate is characterized by a large temperature difference between day and night. The sun shines during the day and the temperature drops sharply at night, so it is necessary to keep warm. According to the statistics of Xizang Autonomous Region Meteorological Bureau, the annual average temperature in southern Tibet is 8℃, and that in northern Tibet is 0℃. In southeastern Tibet, the weather is mild in winter, such as late autumn in the north, and the average daily maximum temperature in December and January often exceeds 10℃. Compared with some cities in northern China, going to Tibet for the winter is not a joke.
Ice and snow Xinjiang
The world of ice and snow is not unique to the northeast. In the northwest of China, ice and snow are also a beautiful landscape in winter. In winter, Xinjiang is rich in ice and snow. From the end of October to the end of March of the following year, the winter here lasts for more than five months.
Being located in the hinterland of Asia, Xinjiang, as the most typical temperate continental climate zone, shows the winter Leng Xia fever extremely clearly. In Fuyun County, Altay region, there was an extreme low temperature of -51.5℃. Although Xinjiang is far away from the ocean and lives inland, surrounded by high mountains, the ocean airflow is difficult to reach, and the precipitation is much less than that in the northeast, with the influence of Altai Mountain, Kunlun Mountain and Tianshan Mountain, Xinjiang has formed a unique landscape of rivers, lakes and glaciers. More than 20 inland rivers, lakes with a total area of 9,700 square kilometers and more than 18,600 glaciers have created a unique ice and snow world.
Summer in winter
Hainan can be said to be an exception in the winter when the country is generally "cold". As a maritime tropical monsoon climate zone, the annual temperature difference here is less than 15℃, and the climate conditions are special in the place where "flowers often bloom in four seasons and there is no winter in summer". In January, the average temperature in most areas here was still around 19℃. When northerners come here, they can often "have another summer" in a year.
(Source: China Meteorological News Editor: Wang Ruojia)