| Chapter I. Physical Geography |
1.3
Climate
Features
China lies mainly in the northern temperature zone under the influence of monsoon. From September and October to March and April next year, monsoon blow from Siberia and the Mongolia Plateau into China and decrease in temperature difference of 40'C between the north and south. The temperature in China in the winter is 5 to 18'C lower than that in other countries on the same latitude in winter. Monsoon blows into China from the ocean in summer, bringing with them warm and wet currents, thus rain.
The monsoon climate allows southern China to have continuous precipitation [Fig1.7] for several months. The 500 mm isohyet line roughly divides the precipitation: north of it, rain is scarce while south of it rain is abundant. As for the temperature, it抯 preferable to discuss it in terms of the seasons. The temperature is pronounced due to the monsoon climate. Wind is chiefly determined by the pressure systems. Following the advance and retreats of the monsoons, a series of special weather phenomena occurs: cold waves, plum rain, and typhoons.
Great differences in climate are found from region to region owing to China's extensive territory and complex topography. The northern part of Heilongjiang Province in northeast China has no summer. Hainan Island has a long summer but no winter; the Huaihe River valley features four distinct seasons; the western part of the Qinghai-Tibet Plateau is covered by snow all year round; the southern part of the Yunan-Guizhou Plateau is spring-like all the year; and the north western inland region sees a great drop of temperature in the day.