This year was supposed to be a warm winter, so why is our country "the only coldest in the world"?

Recently, North China broke the historical low temperature record for the same period and maintained a low level, which is the result of the cold air from central and eastern Siberia moving straight south. The situation and path of this cold wave are similar to the "super polar path", which is a minority of the minority in classic textbooks. The current cold in China is very different. Other places in the world, especially northwestern Europe, are very warm. The temperature in the Arctic Circle is above 0℃, which is warmer than North China, which is 30 degrees south of latitude.

1. The recent cold wave caused many places in North China to break the historical low temperature records for the same period

In the past 20 days, the lowest temperatures at 38 national stations broke the historical December lowest temperature records (this number may differ slightly from other earlier published data due to different statistical days, the same below)

Taking Daxing Station in southern Beijing as an example, the lowest temperature on the 17th was -18.8℃, breaking the December lowest temperature record of -18.3℃ on December 27, 1966.

But this temperature is not even among the top ten lowest winter temperatures recorded at the station.

Interestingly, the lowest temperature on that day at the Beijing Representative Station Observatory, which is only 13 kilometers away from Daxing Station, was only -15.5℃, ranking 8th in its December low temperature record, and far from the historical record of the lowest temperature in winter.

As can be seen from the four tables above, the coldest time in Beijing is usually February, which is still early.

This cold wave in Beijing is still quite far from the lowest temperature in history, but this is not necessarily the case in other places. Nine national stations broke the record for the lowest temperature of the year.

The most obvious situation is in Datong in northern Shanxi. The lowest temperatures on December 16 and 17 this year occupied two of the top three lowest temperatures in history. In addition, there were three days in January that were among the top ten. It can be said that the beginning and end of 2023 were the coldest years in Datong's history.

2. The current cold wave weather situation is unusual

The cold wave weather that affects China is a large-scale, even planetary-scale weather phenomenon. It is relatively easy to study in meteorology and may be one of the earliest and clearest weather types studied in China's meteorology. A picture from a classic textbook can highly summarize the origins and development of China's cold wave as follows:

The main points of this conclusion are: the cold wave cold air that affects my country mainly enters the cold wave key area - Western Siberia from three routes: the west route (most), the northwest route (more), and the transpolar north route (least), and then moves eastward from northern Xinjiang to the south to affect my country. There is another route in the figure (the dotted line in the east), which is close to the type II transpolar route, but is more easterly, does not pass through the cold wave key area, and goes directly southward from Central Siberia to my country.

This research result was completed in the 1970s and has basically not been updated since then, becoming a classic. This article does not discuss whether there is any need for improvement in this classic content (personal opinion: whether it is due to the limitations of the research at that time or due to possible climate change, it should be improved).

By referring to this classic to analyze the process of this cold wave, especially the recent cold air situation after the cold wave, it is not difficult to find that the current situation is a path that is more eastward than the atypical superpolar path in the dotted part above. The type II superpolar path is already the least type of cold wave, and the atypical superpolar path is naturally less eastward than the type II path. This path is even more eastward than the atypical superpolar path, which can be said to be rare among the rare ones. It is not unfair to call it an alternative.

The current cold air situation affecting my country (represented by December 19)

In fact, the current cold front is not strong at all. The coldest place in dark blue in the above picture - East Siberia - was only -40 degrees Celsius during the coldest period (as shown in the picture below at 05:00 on the 20th). You may think it is very cold, but you should know that the record for extreme low temperatures in Siberia in winter is -80 degrees Celsius! It is the coldest place on earth.

This cold air, which is not extreme, has caused relatively extreme cold in central and eastern my country. The main reasons can be attributed to two points: 1. It is close - in central and eastern Siberia rather than western Siberia; 2. It comes quickly - directly moving south instead of moving eastward and southward like most cold air.

This feature will continue in the next few days, but one major change is that the cold air in central and eastern Siberia, which is its source, will become weaker and move further eastward. The impact on our country is that the south will continue to be colder, while the colder weather in the north will gradually weaken and return to normal. Even places as far north as Mohe will turn warmer.

3. The unique situation has created "the only cold place in the world", and the temperature in the Arctic Circle is warmer than that in North China

As mentioned above, the current cold wave situation is very unusual and niche, so it is not surprising that the current cold in China caused by it is also unusual. The Chinese public feels that this winter is very cold, but in fact, people in most other places feel that it is quite warm, especially in northwestern Europe. We still look at the ground temperature at 2 meters at 14:00 on the 19th in the above model. At the warmest time of the day here, it is much colder than the colder time of the day in the higher latitudes of Central and West Asia and Europe:

The European Center predicted the temperature at 2 meters above the ground at 14:00 on the 19th at 08:00 on the 19th (very close to the actual situation)

Let's look at the actual meteorological observation temperature at the same time: the warmest area in the world at the same latitude is the coastal lowlands in northern Norway under the influence of the Atlantic warm current. The temperature is generally 2 to 4 degrees Celsius above zero. It has entered the polar night here, and the temperature is this warm all day long. In terms of temperature alone, it is much warmer than North China, but if you consider the feeling of basking in the sun, it may not be the case.

You know, the places along the northern coast of Norway are around 70 degrees north latitude, while the area around Beijing is around 40 degrees north latitude. It is 30 degrees north and still warmer than ours. Who can we ask for justice? The atmosphere and the ocean.

In fact, it is normal for northwestern Europe to be warmer than North China in winter. The main reason is the westerly wind belt in the atmosphere combined with the distribution of land and sea, and the secondary reason is the warm and cold currents in the ocean.

The common result is that the east of the ocean in the middle and high latitudes is warmer than the west of the continent, and vice versa. Europe is warmer than East Asia at the same latitude, and the western part of North America is warmer than the eastern part. The larger the area of ​​the ocean and continent, the greater the difference. Eurasia is much larger than North America, and the Pacific Ocean is much larger than the Atlantic Ocean. Therefore, the degree to which Europe is warmer than East Asia is significantly greater than the degree to which Seattle is warmer than New York.

Finally, let me say one thing: the previous winter was so cold, how about the next winter? What is the overall impact of global warming?

To be honest, it is difficult to have a specific, definite and completely accurate forecast conclusion. However, from the perspective of rules and probability, it should not happen. In experience, due to the long winter, the cold and warm trends of the previous winter and the next winter are rarely completely consistent, and the winter forecast of the National Climate Center does not support the extremely cold situation in the next winter.

In addition, China's current cold period is relatively local in the world, and does not change the overall situation that 2023 is very likely to become the warmest year in global history. In another 10 days, the results will be out.

Let's wait and see.