After the Spring Festival holiday, it coincides with the rainy solar terms, but there is not much precipitation, and the warming becomes the main character.
Since February 18, my country's central and eastern regions have started a warming mode with clear blue skies and gusts of westerly winds.
However, the west wind blowing on the face cannot hold back the rising temperature.
In Inner Mongolia, Northeast China, North China, Huanghuai, Jianghuai and other regions, the temperature generally rebounded by 6-10℃, and in eastern Inner Mongolia, Hebei, Beijing and other places, the temperature rose by 12-18℃.
According to weather monitoring on the 20th, the
highest temperature of
365
weather observation stations
across the country
exceeded the historical extreme value during the same period in February.
Among them, the highest temperature in Shijiazhuang is 24.2℃ and that in Zhengzhou is 23.7℃.
What is the concept of 24℃?
Equivalent to
the temperature level in May
of the year
!
Netizens sighed on Weibo, "You can wear short sleeves!"
So, what are the reasons for the continuous increase in temperature in many places? Is it due to the "foehn effect" and what are the pros and cons for agricultural production?
We interviewed meteorological experts in Henan, Hebei and Shandong.
The temperature rises everywhere, and the reasons for the impact are actually different.
According to
Henan
Meteorological Station chief forecaster Province Zhang Ning introduction, the main reason for the recent Henan temperatures continue to rise due to the high latitudes of East Asia is weak cold air forces, our country most of eastern controlled by the warm air mass, the weather is fine, and the prevailing westerly winds and ground south wind.
According to
Hebei
Meteorological Station chief forecaster province Zhangjiang Tao introduction, the Hebei warming is under the influence of warm air mass, warming areas, especially in central and southern Hebei Province, long time no cold air or cold air caused by weak forces.
In
Shandong
, Shi Qian, the chief forecaster of the Provincial Meteorological Observatory, said that due to the coordination of the warm ridge and the warm advection in the southwest, strong southerly ground winds are the main cause of the temperature increase.
First of all, what is the Foehn effect?
Generally agreed that the
foehn is a form of forced dry hot wind power caused by the terrain over mountain air sink caused
,
in latitude relative height of not less than any mountain of 800 to 1000 m are possible.
In fact, whether the water vapor phase change occurs during the rise and fall of the airflow is only related to whether a different formula is introduced in the estimation of the foehn wind temperature, and does not shake the
core element of
its warming mechanism
: when the air mass rises from the ground, it is not obtained in an ideal state. Or lose heat, but after rising, the gas block expands due to the decrease in pressure, which consumes internal energy and causes the temperature to drop; when the gas block sinks, the outside air pressure gradually increases, the volume of the gas block is compressed, the internal energy increases, and the temperature also rises. .
If it is really difficult to understand, you can think in another way:
a mountain, without replenishing water, who turned it over with red cheeks and dehydration, only the tongue out of breath?
Of course, no matter how high the body temperature soars, it can't match the temperature increase caused by this topographical influence.
However, Zhang Jiangtao believed that the area along the Taihang Mountains was indeed affected by the Foehn wind. The heating group was concentrated in the front of the mountain and the heating group became warmer.
According to the actual situation, the temperature on the north side of the Taishan Mountains is higher than that on the south side, and the wind force in Jinan and Zibo is also significantly higher, and there is also a partial foehn effect.
The temperature rise this time will have pros and cons on agricultural production.
For
Shandong
, the temperature in the province has risen rapidly recently, and most areas have sufficient sunlight, which has accelerated the process of winter wheat greening, which is beneficial to heat storage in the greenhouse and improvement of the yield and quality of vegetables.
In
Hebei
, Shijiazhuang City Center for Ecology and Agrometeorology expert Cao Chunli also believes that the warming will have little impact on agriculture. For the main crop wheat, the current wheat is still resistant to cold, and the warming will promote the greening.
With the continuous high temperature, under the blessing of sunshine and strong wind, the drought situation in Henan Province has further developed, and the risk of winter wheat suffering from late frost is also increasing.
According to Li Tongxiao, a senior engineer from the Provincial Agricultural Meteorological Service Center, since January, the precipitation in Henan has been 60% less than that of the same period in normal years. 78% of the stations in the province have experienced mild or above-grade meteorological droughts, mainly in the north of the Huaihe River.
In addition, according to the 0-50cm data of the automatic soil moisture monitoring network on February 20, there are 49 (21%) measuring stations in the province with insufficient moisture, mainly distributed in northern Henan, western Henan, southwestern Henan, and parts of central Henan.
At present, winter wheat in various parts of Henan has gradually returned to green, and mild moisture deficiency is conducive to the rooting of wheat roots and improve the use of deep soil moisture.
However, continued drought will affect the normal jointing of wheat, and will have certain adverse effects on wheat fields lacking moisture and without irrigation conditions.
Li Tongxiao reminded that the evaporation of winter wheat will gradually increase after returning to green. Areas with insufficient moisture should pay close attention to the development of drought, make preparations for drought resistance and moisture conservation, and scientifically manage the spring. For wheat fields, properly postpone water and fertilizer to ensure the steady growth of wheat seedlings.
(Source: China Meteorological Administration)