The growth characters and spatial distribution of urban functional area in China from 1984 to 2000

Since the 1980´s, urban functions being strengthened and urban functional areas expanding with high speed has become the marked character of urbanization in China as urban economic system reformation has being deepened more continuously. Based on the analysis of two-time TM images in 1984 and 2000 in PCI, the author defines the confines of urban functional area, analyzes the growth characters of urban functional area in different size and district in China from 1984 to 2000. The results are as follows: from 1984 to 2000, the total urban functional area increases by 7.04 times. The expanded ranges of the king-sized cities (urban nonagriculture population between 1,000,000 to 2,000,000) and the small cities (urban nonagriculture population less than 200,000) are the biggest ones and their urban functional area increases by 9.6 times and 11.1 times respectively, the latter mostly results from the increase on city quantities, and the super-sized cities (urban nonagriculture population more than 2,000,000) expand the least with only an increase of 2.6 times. At the same time, the index Cf (the elasticity coefficient of urban functional area growth, namely, the ratio of area growth rate and urban functional population growth rate) is built to analyze the growth character of urban functional area, and it is evident that Cf of the big cities (urban nonagriculture population between 500,000 and 1,000,000) and the king-sized cities are the biggest ones, which are 7.36 and 5.55 respectively, and the middle-sized (urban nonagriculture population between 200,000 and 500,000) and small cities´ are the least ones, only 3.74 and 3.52 respectively. From 1984 to 2000, urban functional area in South-China district expands the largest with an increase of 12.37 times, and Qinghai-Tibet Plateau district´s is the least one with only an increase of 1.14 times. The amplitudes of other districts are between 6 times to 7 times. So the spatial distribution of urban functional area appears the dynamic pattern with the character that the south proportion is up and the north is down and the difference among districts being shortened apparently. During the period, in Northwest Drought district and Southwest district, urban functional area expands most extensively, Cf of which are 9.37 an- d 6.56 respectively, while in Qinghai-Tibet Plateau district and Southwest district is most intensively, of which are 1.76 and 2.48 respectively. And in other districts, such as North-China, Loess Plateau, the middle and lower reaches of Yangtse River and South-China, their Cf are almost same to the whole country with and average of 4.48.