Scaling Behavior of Chinese City Size Distribution

We have investigated the population distribution of Chinese cities from 1997 to 2006. The rank-size distributions of Chinese cities deviate from the Pareto distribution. For city size distribution of each year we can find a population threshold P-c that characterizes the boundary of the deviation. The cities with population more than P-c follow the Pareto distribution, while the smaller cities deviate from the Pareto distribution. Using P-c for every year, the rank-size distribution from 1997 to 2006 can be written into a scaling form R(P,T) = C(T)P-alpha(T) f(P/P-c(T)), where the Pareto exponent alpha(T) is not equal to the value of Zipf's law and evolutes with time. According this scaling form, the data of the city size distributions of Chinese cities from 1997 to 2006 can collapses to a single curve, which is the scaling function of the city size distribution.