What's the difference between the wind direction in Suzhou in winter and summer? Are there any obvious changes in precipitation in winter and summer? Why?

The causes of wind and its influence on agriculture

The horizontal movement of air is called wind. The characteristics of wind are expressed by wind direction and wind speed. Wind direction refers to the direction of the wind, which is usually divided into eight directions. Wind speed refers to the distance that the air moves in the horizontal direction per unit time, and the unit is meter/second or kilometer/hour, which is usually expressed by wind level. When the average wind force reaches level 6 or above during the forecast period, the Meteorological Observatory will issue a gale warning.

The wind direction changes regularly. The wind always blows from high pressure to low pressure, and the greater the pressure difference, the greater the wind speed. In winter, the air near the ground in the north is cold, dense and high in pressure, so the northerly wind blows in winter. In summer, on the contrary, there is subtropical high in the western Pacific and South China Sea, and the air pressure in the north is low, so southerly winds blow more in summer. This wind direction changes regularly with the seasons, which is called monsoon. China is a monsoon country, with northerly winds prevailing in winter and southerly winds prevailing in summer. Take Suzhou as an example, the frequency of northerly winds in June 5438+1October is 70%, and the frequency of southerly winds in July is 77%. The maximum wind direction in Suzhou is southeast wind and the minimum wind direction is southwest wind.

Suzhou House is located on the eastern coast of Chinese mainland, in the humid monsoon climate zone in the north subtropical zone. It is hot in summer, rainy and humid, dry and cold in winter, with obvious monsoon, four distinct seasons, superior natural conditions and abundant climatic resources.

According to data analysis, the annual average temperature in Suzhou is 15.7℃, the hottest month is July, and the average temperature is 28.2℃. The most Leng Yue is 65438+ 10 month, with an average temperature of 3.0℃; The annual average precipitation is 1094 mm, with the most precipitation and precipitation days in June, the monthly average precipitation is l6 1 mm, and the precipitation days are 13 days. The monthly precipitation in 65438+February is the least, which is 37mm. The precipitation days in 65438+February are the least, with an average of 7 days; Suzhou monsoon changes obviously. Northwest wind and northeast wind prevail in winter, southeast wind prevails in summer, and spring and autumn are alternate seasons of summer monsoon and winter monsoon. Every year from June to July, there is often rainy weather in the mature season of plums in the south of the Yangtze River, which is called "Meiyu". The average plum blossom period in Suzhou is June l 6, July 9, and the average plum rain is 204 mm, but the annual amount is different. 1999 Teto, Meiyu 723mm；; At least in 2000, the amount of plum rain was only 23 mm. Due to the instability of geographical location and monsoon, the climate in Suzhou changes dramatically, and there are often many types of disastrous weather in four seasons. There are droughts, floods and long-term continuous rainfall; There are also short-term strong weather, such as heavy rain caused by tropical storms (typhoons) and low temperature freezing caused by cold waves; There are also some destructive and disastrous weather, such as strong convection (hail, tornado, strong wind) and thunderstorms.