Temperature and precipitation in winter and summer in Hangzhou

Hangzhou is located in the transition zone of the subtropical zone, which is warm and humid, with four distinct seasons, abundant sunshine and rainfall. In a year, with the alternating control of winter and summer monsoon, the atmospheric circulation background, main weather systems and weather conditions will change obviously seasonally, forming the climate characteristics of rainy spring, hot flashes in summer, dry autumn and wet and cold winter. Due to the complex and diverse topography and uneven terrain in Hangzhou, the regional distribution of climate resources such as temperature, light, water and wind is uneven, and local microclimate resources are rich. However, due to the instability of monsoon advance and retreat and duration, especially the great change of monsoon intensity, abnormal cold, hot, dry and wet conditions often lead to disastrous weather and climate events. The main climatic features of Hangzhou are as follows:

First, the light and temperature are synchronized, and the rain and heat are the same season.

Due to the influence of winter and summer monsoon, Hangzhou has formed a climate characteristic of good coordination of light, heat and water in the same season. After the spring, the total solar radiation increases month by month, the temperature rises synchronously, and the rain and heat increase in the same season; From May to June, from spring to summer, precipitation in Hangzhou began to enter the peak period, and the temperature was moderate. The total solar radiation reaches the highest value in midsummer season (July-August), which is also the high temperature period of the year. Controlled by the subtropical warm air mass, the precipitation after the plum rain is obviously reduced compared with the previous period, which is prone to high temperature and drought. Historically, the highest daily temperature in Hangzhou reached 39.9℃. From summer to autumn in September, the light and temperature decrease simultaneously. Influenced by typhoon and cold air, autumn rain came. Autumn weather prevails10-165438+10 month. The sunshine is abundant, the daily temperature difference is large, and the light and temperature conditions are better than those in spring. In winter, light, heat and water are at the low point of the year.

Second, the temperature rises early, quickly and in a wide temperature range in spring.

Hangzhou has a vast area of low mountains and hills, and the plains and basins along the river are surrounded by mountains and waters, with obvious topographic and climatic characteristics. The average monthly temperature in winter (represented by 65438+ 10) in the eastern part of Ningshaoping Plain is 0.9- 1.3℃ higher than that in the western hilly valley, but the first day of recovery is ≥ 10℃ which is the same as that in the eastern plain. On the first day of temperature rise ≥ 15℃, Lin 'an is 3 days earlier than Ningbo; From the initial warming day of ≥ 10℃ to the initial warming day of ≥ 15℃, Lin 'an takes 22 days, while Ningbo in the east takes 25-26 days, and the spring warming is earlier than that in Ningshao Plain. Comparing the average temperature rise in Ningbo and Xiaoshan in the first half of the year, we can see that the average temperature rise in basin and valley areas from February to April is greater than that in plain areas. The daily temperature range in mountain basins and valleys is obviously greater than that in plains. The annual average daily temperature range is 1 1.0℃ in Changhua and/kloc-0.1℃ in Jiande, while it is only 7.9-8. 1℃ in the northeast plain of Hangzhou, which is 2-3℃ lower than that in mountain basins and valleys. This is another climate feature of Hangzhou.

Third, the climate is more suitable and the resources are abundant.

Hangzhou city spans two hot zones, with latitude of 1.3 in the north and south, but the annual average temperature is 2.5℃, the active accumulated temperature is 1000℃, the precipitation in mountainous and plain areas is over 700 mm, and the annual sunshine hours are over 300 hours. This shows that the climate resources in Hangzhou are not only zonal differences, but also topographical microclimate differences.

Xin 'anjiang Reservoir Area, Meicheng Liangjiang Plain and Shou Chang Basin in the southwest of Hangzhou are surrounded by mountains, and there is water transfer in the middle, which is a climatic zone with more precipitation, the best heat condition, the longest frost-free period and superior wintering conditions in Hangzhou.

The river network plain and coastal plain in the northeast of Hangzhou are open to the north, with less precipitation, abundant sunshine, cold winter and poor heat conditions. The valley plains and basins in the central part are between the north and the south, with suitable climate, moderate precipitation and excellent heat conditions. In addition, the superior microclimate resources in Sanjiang basin have created very beautiful natural scenery. Mountains and rivers are interdependent, trees are lush, and scenic spots and historical sites are distributed among them, forming the main scenic tourist area of the southern line of Hangzhou.

In the vast mountainous areas of Hangzhou, the vertical climate difference is significant and the rainfall is abundant. The temperature decreases with the increase of height, and the rainfall in mountainous areas below 1000 meters increases with the increase of height, which constitutes a complex and diverse three-dimensional microclimate.

Fourth, meteorological disasters occur frequently.

Taking Hangzhou as an example, the annual variation of monthly average temperature in winter and autumn can reach above 6℃, and it is also around 4℃ in spring and summer. The interannual variation of annual precipitation can reach more than 1 times (952-2355mm), and the interannual variation of monthly precipitation can reach more than ten times. The interannual variation of annual sunshine hours can also exceed 600 hours (1576-2256 hours). It is precisely because of the great annual change of climate factors that there is no rain for a long time in some years and there is heavy rain in some years, which brings frequent meteorological disasters.

The spring is chilly and the spring rain is continuous; Summer rainstorm, strong convection, high temperature and dry weather; Autumn temperature is low, with early frost and late frost; However, meteorological disasters such as cold wave and heavy snow in winter often bring serious casualties and property losses to all walks of life. For example: 1954, 1983, 1994,1996,2001floods; 1967, 1978, 1994 and droughts in 2003; 1956, 19 1, 1963, 1972, 1974, 1988 and 2005 were all affected by typhoons.