Division of seven temperature zones

According to the cumulative activity temperature of each region, the regions are divided according to the heat index required for agricultural production:

1, 23 26 ′ n (Tropic of Cancer) to 23 26 ′ s (Tropic of Cancer) is tropical.

2. North latitude (south latitude) 23 26 ′ to north latitude (south latitude) 66 34 ′ (Arctic Circle, Antarctic Circle) belongs to the north-south temperate zone.

3. The north-south cold zone is 66 34 ′ north latitude to 90 north latitude (south latitude).

Most of China is located in the north temperate zone, and a few are located in the tropics; It is divided into cold temperate zone (northern Heilongjiang and eastern Inner Mongolia), middle temperate zone (northeast, most of Inner Mongolia and northern Xinjiang) and warm temperate zone (most of the middle and lower reaches of the Yellow River and southern Xinjiang).

Subtropical (south of Huaihe River in Qinling Mountains and east of Qinghai-Tibet Plateau), tropical (southern Yunnan, Leizhou Peninsula, southern Taiwan Province and Hainan Province), plateau climate.

Extended data:

China temperature area ratio:

Among all the temperature zones, the cold temperate zone only accounts for 1.2% of the total land area. The climate in most parts of the Qinghai-Tibet Plateau is extremely cold, accounting for 26.7% of the total land area, and the rest accounts for 72. 1% of the total land area, belonging to middle temperate zone, warm temperate zone, subtropical zone and tropical zone. Therefore, China is dominated by a warm climate.

World climate:

1, low latitude climate

The climate at low latitudes is mainly controlled by equatorial air mass and tropical air mass. The main circulation systems that affect the climate are equatorial convergence zone, Wacker circulation, trade winds, equatorial westerly winds, tropical cyclones and subtropical high.

The annual radiation difference of the ground-air system is too large, so the annual temperature is high. The average temperature in Leng Yue is above 15 ~ 18℃, and the annual evapotranspiration may be above 130cm. This area can be divided into five climate types, among which tropical arid and semi-arid climate types can be divided into three subtypes.

2. Mid-latitude climate

This is an area where tropical air masses and polar air masses compete with each other. The main circulation systems affecting climate are polar front, prevailing westerly wind, extratropical cyclone and anticyclone, subtropical high and tropical cyclone. The radiation energy balance in this area changes greatly in one year, so the four seasons are distinct. The average temperature in Leng Yue is below 15 ~ 18℃ and above 10℃ in April ~/February.

The annual potential evapotranspiration is between130 and 52.5 cm. The non-periodic change of weather and the seasonal change of precipitation are significant. In addition, the mid-latitude belt in the northern hemisphere has a large continental area, which is influenced by the thermal contrast between land and sea and the towering terrain, making the climate in this area more complicated. There are 8 climate types in this area.

3. Plateau and mountain climate

On the plateau, with the increase of altitude, the climatic factors also change, resulting in obvious vertical zonality of alpine climate. In order to distinguish the climate affected by altitude and latitude, and because the alpine climate is limited to a local area, the plateau climate is classified as a large category and is not included in the lowland classification system.