Introduction to Zhejiang geography Ppt courseware

The straight-line distance from east to west and from north to south is about 450km, and the land area is105,500km2, which is 1.06% of that of China. It is one of the smallest provinces in China. Hills account for 70.4%, plain basins account for 23.2%, rivers and lakes account for 6.4%, and the cultivated land area is only 208 1.7 million hectares, so it is said that "seven mountains, one water and two fields". The terrain inclines from southwest to northeast, which can be roughly divided into six terrain areas: northern Zhejiang plain, western Zhejiang hilly area, eastern Zhejiang hilly area, central Jinqu basin, southern Zhejiang mountainous area, southeast coastal plain and coastal islands. [2]

Fold landform

The topography of Zhejiang is stepped from southwest to northeast, with mountains in the southwest, hills in the middle and low alluvial plains in the northeast. "Seven mountains, one water and two fields" is a generalization of Zhejiang's topography.

The alluvial plain with dense water networks in northern Zhejiang, the coastal hills in eastern Zhejiang, the mountainous areas in southern Zhejiang, and the island landform in Zhoushan can be described as mountains, rivers, lakes and seas. In the southwest, there are many mountains with a distance of more than 1000 meters, among which Huangmaojian Peak in Longquan is the highest mountain in Zhejiang Province, with an altitude of 1.929 meters. The topography is dominated by hills, mountains and basins, accounting for 70.4% of the total area of Zhejiang Province. The plain area is 23.2%, including Hangjiahu Plain (Hangjiahu, Jiaxing and Huzhou), Ningshao Plain (Ningbo and Shaoxing), Jinliqu Plain (Jinhua, Lishui and Quzhou) and Wen Tai Plain (Wenzhou and Taizhou).

Folding climate

Zhejiang has a subtropical monsoon climate with four distinct seasons, moderate annual temperature, abundant sunshine, abundant rainfall, moist air, synchronous seasonal changes of rain and heat, diverse climate resources and numerous meteorological disasters. The annual average temperature is 15 ~ 18℃, the lowest and highest temperatures are in June and June respectively, and the rainfall concentration period is in May and June. The extreme maximum temperature is 44. 1℃, and the extreme minimum temperature is-17.4℃. The average annual rainfall in Zhejiang Province is 980 ~ 2000mm, and the average annual sunshine hours are1710 ~ 2100h.

In spring, the East Asian monsoon is in the alternate season between the winter wind direction and the summer monsoon. The north-south airflow frequently meets, and the low pressure and frontal activity intensify. In spring, the climate in Zhejiang is cold and rainy, and there are often strong winds along the coast and offshore. The rain in Zhejiang Province is increasing, and the weather is unpredictable. It is said that "a child's face changes three times a day in spring". The average temperature in spring in Zhejiang is 13 ~ 18℃, and the temperature distribution is decreasing from inland areas to coastal and island areas. The precipitation in Zhejiang province is 320 ~ 700 mm, and the distribution of precipitation gradually decreases from southwest to northeast coastal areas. The rainy days in Zhejiang province are 4 1 ~ 62 days. The main meteorological disasters in spring are rainy and low temperature in late spring.

In summer, with the establishment of the summer monsoon circulation system, the southeast wind prevails in Zhejiang, and the subtropical high activity in the northwest Pacific has an important influence on the weather in Zhejiang, while the cold air from the north to the south still has a certain influence on the weather in Zhejiang. The rainy days in Zhejiang province are 32 ~ 55 days. The main meteorological disasters in summer are typhoon, rainstorm, drought and flood.

In autumn, the summer monsoon gradually weakens and transitions to the winter monsoon. Cyclone activity is frequent, frontal precipitation is more, and temperature changes greatly. The average autumn temperature in Zhejiang Province is 16 ~ 2 1℃, which is higher in the southeast coastal and central areas and lower in the northwest mountainous areas. The precipitation is 2 10 ~ 430mm, with more precipitation in the central and southern coastal mountainous areas and less precipitation in the northeast, but its interannual variation is great. It rains for 28 ~ 42 days in all parts of Zhejiang Province.

In winter, the strength of winter monsoon in East Asia mainly depends on the activity of Mongolian cold high pressure, while the weather in Zhejiang is affected by the cold air mass in the north (that is, winter monsoon), and there are relatively few types of weather processes. The winter climate is characterized by abundant sunshine, cold and little rain and dry air. The average temperature in winter is 3 ~ 9℃, and the temperature distribution is decreasing from south to north and from east to west. Precipitation 140 ~ 250 mm, except for the northeast islands, there is little difference in other places; The rainy days in Zhejiang province are 28 ~ 4 1 day. The main meteorological disasters in winter are cold wave, rain and snow.