Spatiotemporal Differentiation Structure Evolution of Population and Land in Zhejiang Urban Agglomeration

  Objectives  As the acceleration of global urbanization, traffic congestion and environmental degradation have emerged in the urban area. Based on the light and statistical data, this paper studied the spatial evolution between urban people and land, and revealed the significance of its coupling and coordination characteristics for the sustainable development of cities.

  Methods  For primary data, a series of preprocessing are needed to eliminate the problems of supersaturation and discontinuity of inter-annual data. Based on the lighting threshold, this paper excerpted the built-up areas of urban agglomeration in Zhejiang Province year by year, compared them with the statistical data, and analyzed the corrected data source relatively. Firstly, based on the order-scale distribution model of urban order and urban population in Zhejiang Province from 1992 to 2020, we made a dynamic analysis on population aggregation and distribution in its development process. Then, we constructed the population-land urbanization allometric growth model by using population and light area, as well as judged the spatialization of man-land relationship in urban development. Finally, according to the lag phenomenon of population growth relative to land development, we proposed an allometric growth model with lag factor, and used the lag term model to judge the characteristics of unequal growth of people and land in different cities.

  Results  The structural system of urban agglomeration is relatively mature in Zhejiang Province, and the distribution of cities is reasonable. However, the primacy of city is gradually improved, and the population is gradually gathering. The results of allometric growth model show that the man-land relationship of urban agglomeration in Zhejiang Province is generally low in the eastern coastal cities and high in the western inland cities, and the planning of the four metropolitan areas is reasonable. The improvement of fitting accuracy of the proposed model with lag factor obviously shows that there is lag effect between population urbanization and land urbanization, with an average increase of 6.47% and the highest increase of 12.61%. Among the influencing factors on land urbanization, the dominant factor in Hangzhou is the existing population in urban areas, while the dominant factor in Ningbo is the new population in urban areas.

  Conclusions  The proposed allometric growth model with lag factor can correct the model errors and improve the fitting accuracy of urban man-land relationship. It can also effectively evaluate the temporal and spatial evolution characteristics of man-land relationship in regional system, explore its development and put forward countermeasures.