Climatic characteristics of Jinan and its influence

The annual average temperature in Jinan is 14.7℃, the annual average precipitation is 67 1. 1mm, and the annual sunshine hours are 26 16.8 hours. The hottest month in Leng Yue is 65438+ 10, and the monthly average temperature is -0.4℃. The hottest month is July, with an average monthly temperature of 27.5℃. The extreme minimum temperature was-14.9℃, which appeared on1February 7, 972. The extreme maximum temperature is 40.5℃, which appeared on1June 23, 997. Frost generally starts from the middle of 165438+ 10, and ends from late March to early April of the following year, with a frost-free period of 235 days. The dominant wind direction is southwest and northeast, followed by east, north and south, and at least northwest wind. The main meteorological disasters are: strong wind, frost, hail, rainstorm and flood, drought, fog, lightning and so on.

Jinan belongs to a warm temperate climate zone. Due to its geographical location, it has formed a continental monsoon climate with hot summer and cold winter and four distinct seasons. Winter is controlled by polar or polar deformed continental air masses, and is constantly attacked by dry and cold air masses from Siberia. The northwest, north and northeast winds prevail, resulting in dry and cold weather, clear weather and less precipitation in winter. Influenced by tropical and subtropical ocean air masses in summer, the northwest monsoon in winter is replaced by the southeast wind in summer, so southwest, south and southeast winds blow, resulting in hot and humid summer, concentrated rainfall and thunderstorms. Spring and autumn are the transitional seasons between winter monsoon and summer monsoon, and the wind direction is changeable. Because the wind changes obviously with the seasons, it forms the climate characteristics of Leng Xia in winter and uneven rainfall in four seasons.

The four seasons climate in Jinan is characterized by dry and windy spring, hot and rainy summer, cool autumn weather and long dry and cold winter. Spring (March-May): the temperature rises rapidly, the daily range is large, the weather is dry, the wind is strong, the precipitation is small, the evaporation is large, the soil loses water quickly, and the spring drought is serious. The average daily range in spring is between 10 ~ 14℃, which is the largest in the whole year. There are many strong winds in spring, especially in April, with an average wind speed of 4m/s, which is the largest month of the year. The gale in spring accounts for about 56% of the gale days above magnitude 8 in the whole year. The precipitation in spring is generally about 90mm, accounting for only about 14% of the annual precipitation. Summer (June-August): It is hot in summer with an average temperature of 26.7℃. This season is not only hot and rainy, but also has the characteristics of rainy and hot seasons. The average precipitation in summer is about 450 mm, accounting for more than 65% of the annual precipitation. Only in July, the average precipitation days are about 15 days, and the number of rainstorm days with daily precipitation greater than or equal to 50mm is concentrated in July and August, accounting for about 65% of the annual rainstorm days. In early summer, droughts often occur due to high temperature, strong wind and low humidity. Autumn (September-165438+1October): The rainy season is basically over, the westerly belt in the upper air gradually strengthens southward, and the southeast monsoon gradually transits to the northwest monsoon, resulting in a brief "crisp autumn" weather with weak wind speed, less clouds, excellent visibility and fine weather. The average temperature in autumn is 15.5℃ and the average precipitation is105.438+0mm, but too little rainfall will cause autumn drought. Winter (12- February of the following year): controlled by Mongolian cold high pressure, full of cold northerly winds. The continuous invasion of cold air causes the temperature to drop continuously. The average temperature in winter is about 65438 0℃, the maximum frozen soil depth is 42 cm, the maximum snow depth is 22 cm, and the winter precipitation is about 20 mm, accounting for only 3% of the annual precipitation. Rain and snow are scarce, the north wind is frequent, and it is dry and cold all winter.