Autumn, also known as fall, the third season of the year, the transition from summer to winter season, the northern hemisphere for the September to November, the southern hemisphere for the March to May, the astronomical fall equinox to the winter solstice. Meteorologists study climatological criteria is: after the heat, the five-day average temperature stabilized at 22 degrees below even into the fall, below 10 degrees when the end of autumn.

Expanded Information

The autumnal equinox is a festival that characterizes the change of seasons. On the day of the autumnal equinox, the sun is located at 180 degrees of the yellow longitude, the sunlight is almost directly on the equator, and the day and night are almost equal in length. At this time, the southern region of the candidate temperature generally dropped to 22 ℃ below, into the cool autumn." An autumn rain is a cold." A stream of cold air from the south, meeting with the gradually decaying warm and humid air, produces rainfall again and again, and the temperature also falls again and again. In the northern part of the Northwest Plateau, the daily minimum temperature fell to below 0 ℃, you can already see the sky flocculent fluttering, the earth wrapped in silver magnificent snow scene.

After the autumnal equinox, the rainfall in most parts of southern China decreased significantly, and torrential rain and heavy rain generally seldom appeared; however, the number of days of rainfall increased instead, and it was often cloudy and rainy, and the rate of night rains was also higher. The famous Tang Dynasty poet Li Shangyin's famous line "Bashan night rain rises in the autumn pool" vividly depicts the climate characteristics of the southern autumn night rain.

Southern areas and Liangshan Prefecture have a lot of rain in the fall, and the moisture damage is serious, which has a great impact on the fall harvest, fall plowing and fall planting. To seize the sunshine harvest, moisture prevention, grasp the "three autumn" production quality and progress. At the same time, but also to make full use of the autumn rain, soil moisture better meteorological conditions, without losing time to engage in afforestation, and strive to improve the survival rate of saplings.

Reference:

. Baidu Encyclopedia - Autumn