Historical weather this month

Temperatures in many parts of the country have risen to historical extremes. Why is the temperature so high in January this year?

Before the first month, it smelled like summer.

At 2 pm on the 20th, the highest temperature in Beijing exceeded 20℃. Due to the rising temperature, many Beijing residents have taken off their thick down jackets, cotton-padded jackets and other warm clothes and put on light clothes. However, starting from 2 1, the temperature in Beijing will drop step by step, and it is expected that the maximum temperature on the 23rd and 24th will drop to 6℃. In addition, it is expected that there will be light snow or sporadic light snow in the northern part of Beijing from the night of the 22nd to the day of the 23rd.

Hebei: The rebound is accelerating, with the highest temperature exceeding 20℃ in most parts of central and southern China.

On the 20th, the temperature in most parts of central and southern Hebei Province stood steadily above 20℃, and the highest temperature in Handan will soar to 27℃ on Sunday.

Tianjin: The temperature exceeded 20℃ for two consecutive days, setting a new record for the same period in history.

At noon on the 20th, the temperature in several jurisdictions in Tianjin exceeded 20℃. The highest temperature appeared in the urban area of Tianjin, reaching 23℃, which set a new record for the highest temperature in Tianjin since 195 1, which is the second consecutive record for the same period since1.3℃ appeared on the 9th of/kloc-0.

It seems that the temperature in Jiangsu in early summer exceeds 25℃.

There is still hot weather in the south. On the 20th, the highest temperature in Jiangsu Province was generally above 20℃, with Yixing exceeding 25℃, which was significantly higher than the average temperature in the same period last year. However, according to the forecast of the local meteorological department, due to the influence of cold air, Jiangsu Province will usher in a round of cooling from 22nd to 23rd, with the cooling range of about 10℃.

Liu Mei, chief forecaster of Jiangsu Meteorological Observatory: According to the highest temperature, from 20th to 2 1, the whole province is at 23℃ to 24℃; From 22nd to 23rd, the highest temperature in most parts of our province was 10℃ to 15℃, and the lowest temperature was below 5℃.

Shanghai: The highest temperature today may reach 23℃

The temperature in Shanghai continues to warm up, the long-awaited magnolia flowers begin to bloom, and the trees turn white, which means that the footsteps of spring have arrived.

According to the official news of China Meteorological Bureau, the temperature in Inner Mongolia, Northeast China, North China, Huanghuai, Jianghuai and other areas generally rises by 6 ~ 10℃, and the temperature in eastern Inner Mongolia, Hebei and Beijing rises by 12 ~ 18℃.

Meteorological monitoring on the 20th showed that the highest temperature of 365 meteorological observation stations nationwide in February exceeded the historical extreme value in the same period.

What are the reasons for the recovery in various places? Let's see what meteorologists from all over the world say.

The reasons for the soaring temperature in different places are actually different.

According to Zhang Ning, chief forecaster of Henan Meteorological Observatory, the main reason for the recent temperature rise in Henan Province is that the cold air force in high latitudes of East Asia is weak, and most of the central and eastern regions are controlled by warm air masses, with fine weather and prevailing westerly and southerly winds on the ground.

According to Zhang, chief forecaster of Hebei Meteorological Observatory, the temperature rise in Hebei Province is caused by the influence of warm air mass, especially in the central and southern parts of Hebei Province, where there is no cold air for a long time or the cold air force is very weak.

In Shandong, Shi Qian, chief forecaster of the Provincial Meteorological Observatory, said that due to the cooperation of warm ridge and southwest warm advection, the southerly wind on the ground is the main reason for the temperature rise.

This has nothing to do with. Brahma effect? Related?

It is generally believed that foehn wind is a kind of dry-hot wind produced by topographic forces forcing the mountain airflow to sink, and the relative height of mid-latitude is not less than 800? Any mountain with an altitude of 1000 meters may appear.

In fact, whether vapor phase transition occurs during the ascending and descending process of airflow is only related to whether different formulas are introduced to estimate the foehn temperature, and it does not shake the core elements of its warming mechanism: when the air mass rises from the ground, although it does not increase or decrease heat in an ideal state, the air mass expands due to the decrease of pressure after rising, consuming internal energy, leading to the temperature drop; When the air mass sinks, the external air pressure gradually increases, the volume of the air mass is compressed, the internal energy is increased, and the temperature is also increased.

If it is really difficult to understand, you can also put yourself in the other's shoes: a high mountain, without adding water, who turns red and dehydrated, and only sticks out his tongue to gasp?

Of course, no matter how soaring the body temperature is, it can't compare with the temperature rise caused by this topographic influence.

This time, Zhang believes that the area along Taihang Mountain is really affected by the burning wind, and the heating mass is concentrated in the piedmont area, and the heating mass is getting warmer.

According to the actual situation, the temperature on the north side of Mount Tai is higher than that on the south side, and the winds in Jinan and Zibo are obviously stronger, and there is also a local foehn effect.

What is the impact on agricultural production?

This warming has both advantages and disadvantages for agricultural production.

For Shandong, the temperature in the whole province has risen rapidly recently, and sunshine in most areas has accelerated the process of winter wheat turning green, which is conducive to heat storage and warming in greenhouses and improving the yield and quality of vegetables in protected areas.

In Hebei, Cao Chunli, an expert from Shijiazhuang Ecological and Agrometeorological Center, also believes that warming has little impact on agriculture. For the main crop wheat, the current wheat is still cold-tolerant, and warming up will promote greening.

However, with the continuous high temperature and the blessing of sunshine and strong winds, the drought in Henan Province has further developed, and the risk of winter wheat being harmed by late frost has also increased.

According to Li Tongxiao, a senior engineer of Henan Agricultural Meteorological Service Center, since June 5438+ 10, the precipitation in Henan Province has been 60% less than normal, and 78% of the stations in the province have experienced mild and above meteorological drought, mainly distributed in the north of Huaihe River. In addition, according to the 0 ~ 50 cm data of the soil moisture automatic monitoring network on February 20th, there are 49 stations in the whole province (accounting for 2 1%), which are mainly distributed in northern, western, southwestern and central Henan.

At present, winter wheat in various parts of Henan Province has gradually turned green, and mild water deficit is beneficial to wheat roots and improves water use efficiency in deep soil. However, the continuous drought will affect the normal jointing of wheat, and will have some adverse effects on wheat fields lacking water and irrigation conditions.

Li Tongxiao reminded that the evaporation of winter wheat will gradually increase after turning green, and areas with insufficient moisture content should pay close attention to the development of drought, make preparations for drought resistance and moisture conservation, and scientifically do a good job in spring management. The wheat fields with weak growth should be combined with watering for topdressing management, and the wheat fields with strong growth should be appropriately delayed to ensure the stable growth of wheat seedlings.