What is the phenomenon of vernal equinox?

The phenomenon of vernal equinox includes stronger sunshine, fluctuating air pressure, rising temperature and increasing precipitation.

1, sunshine.

(1) On the day of the vernal equinox, the sun shines directly at the equator, and day and night are almost equal. After that, the direct sunlight position gradually moved northward, and the days in the northern hemisphere were long and the nights were short.

(2) The vernal equinox is an important solar term, which not only has astronomical significance: the northern and southern hemispheres are equally divided day and night, but also has obvious characteristics in climate. At the vernal equinox, China entered a beautiful spring scenery except the Qinghai-Tibet Plateau, the northeast, the northwest and the northern part of North China.

(3) On the vast land, willows are green, grass grows in Fei Ying, wheat is jointing, and rape blossoms are fragrant.

2. Air pressure fluctuation.

(1) During the solar term of the vernal equinox, the East Asian trough was obviously weakened, and the ridge activity in the westerly belt was obviously enhanced. From Mongolia to Northeast China, there are often low-pressure activities and cyclones. Low-pressure activities lead cold air to the south, and there is strong wind and sand in the north.

(2) The long wave trough moves eastward, and due to the intersection of cold and warm air masses, there will be continuous rainy and cold weather in late spring.

3. As the temperature rises, the precipitation increases.

(1) During the vernal equinox, the daily average temperature in all parts of China rose to above 0℃ steadily, except for the alpine mountain areas that don't melt all the year round in winter and the areas north of 45 north latitude.

(2) At this time, the severe cold has passed, and the temperature rises rapidly, especially in North China and Huanghuai Plain. The daily average temperature rises to above 10℃ almost at the same time as the rainy areas along the Yangtze River and the south of the Yangtze River, entering a bright spring.

(3) At this time, the precipitation in the south of the Yangtze River increased rapidly and entered the "Peach Blossom Flood" period in spring.