Based on the National Land Use/Cover Database of China(NLUD-C) in the end of the 1980s(the 1980s,hereafter), 1995, 2000, 2005, and 2010, 665 cities were selected to study the size distribution and its changes of urban...Based on the National Land Use/Cover Database of China(NLUD-C) in the end of the 1980s(the 1980s,hereafter), 1995, 2000, 2005, and 2010, 665 cities were selected to study the size distribution and its changes of urban lands in China. In this study, the spatiotemporal evolutions of urban land size distribution as well as the influence of administrative-level on these cities were explored by combining urban spatial positions and administrative-levels. Results indicate that: 1) City size distribution using urban lands was more practical and reasonable than using non-agricultural population. 2) In the 1980s, cities with ascending urban land rank were centralized in Eastern China, specially the Changjiang(Yangtze) River Delta, the Zhujiang(Pearl) River Delta, and Beijing-Tianjin-Hebei region. Cities in Central, Western, and Northeast China mainly indicated descending urban land rank. 3) The transfer of national development focus resulted in cities with ascending urban land rank becoming evenly distributed nationwide; however, this trend was slightly centralized around Chengdu, Chongqing, and Wuhan in different periods. 4) During the 1980s to 2010, the proportion of cities with ascending urban land rank in provincial capitals, municipalities, and special administrative regions(high-level cities, hereafter) was consistently higher than those in prefecture- and county-level cities except for 2005–2010. The ranks of the majority of the prefecture- and county-level cities were mainly descending, supported by ascending; the proportion of cities with unchanged rank is small. This study breaks through the bottleneck of traditional research in the area of city size distribution by examining urban land replacing the non-agricultural population. The current study also provides scientific explanation for the healthy and reasonable development of urban land as well as the coordinated development of population urbanization and land urbanization.展开更多
By using RS and GIS technology,the ecological risk index ( ERI) was constructed based on the analysis of land use change and structural characteristics in urbanization watershed of Songhua River in Harbin section. Aft...By using RS and GIS technology,the ecological risk index ( ERI) was constructed based on the analysis of land use change and structural characteristics in urbanization watershed of Songhua River in Harbin section. Afterwards,the spatial distribution and change characteristics maps of ERI obtained by using block Kriging were analyzed to reveal the spatial and temporal evolution characteristics,change rules and formation mechanisms of ecological risk based on land use under the background of urbanization,and to minimize land use risk during urbanization process. The results showed that during the past 18 years,moderate ecological risk level was major,while proportion of high ecological risk was the lowest,and the area of higher and lower ecological risk region changed most greatly; high and higher ecological risk were focused on urban region and the transition zone from urban to suburban region,while low and lower ecological risk mainly distributed in forestland with higher vegetation coverage,water bodies,grassland,shrub land and so on. Meanwhile,the transition zone from high to low ecological risk was very obvious. In addition,ecological risk became slightly worse in some region due to the transformation from cropland to residential and urban land,while it became slightly better in other regions because of the transformation from cropland to forestland; the center of gravity in lower ecological risk region shifted most greatly,while the shift was the smallest in high ecological risk region,namely 12. 31 and 0. 57 km respectively.展开更多
基金the Young Scientist Fund of National Nature Science Foundation of China(No.41101148)
文摘Based on the National Land Use/Cover Database of China(NLUD-C) in the end of the 1980s(the 1980s,hereafter), 1995, 2000, 2005, and 2010, 665 cities were selected to study the size distribution and its changes of urban lands in China. In this study, the spatiotemporal evolutions of urban land size distribution as well as the influence of administrative-level on these cities were explored by combining urban spatial positions and administrative-levels. Results indicate that: 1) City size distribution using urban lands was more practical and reasonable than using non-agricultural population. 2) In the 1980s, cities with ascending urban land rank were centralized in Eastern China, specially the Changjiang(Yangtze) River Delta, the Zhujiang(Pearl) River Delta, and Beijing-Tianjin-Hebei region. Cities in Central, Western, and Northeast China mainly indicated descending urban land rank. 3) The transfer of national development focus resulted in cities with ascending urban land rank becoming evenly distributed nationwide; however, this trend was slightly centralized around Chengdu, Chongqing, and Wuhan in different periods. 4) During the 1980s to 2010, the proportion of cities with ascending urban land rank in provincial capitals, municipalities, and special administrative regions(high-level cities, hereafter) was consistently higher than those in prefecture- and county-level cities except for 2005–2010. The ranks of the majority of the prefecture- and county-level cities were mainly descending, supported by ascending; the proportion of cities with unchanged rank is small. This study breaks through the bottleneck of traditional research in the area of city size distribution by examining urban land replacing the non-agricultural population. The current study also provides scientific explanation for the healthy and reasonable development of urban land as well as the coordinated development of population urbanization and land urbanization.
基金Supported by the National"863"Project(2006AA12Z104)Natural Science Foundation of Heilongjiang Province,China(F201137)Natural Science Foundation for Distinguished Young Scholars of Heilongjiang University(QL200640)
文摘By using RS and GIS technology,the ecological risk index ( ERI) was constructed based on the analysis of land use change and structural characteristics in urbanization watershed of Songhua River in Harbin section. Afterwards,the spatial distribution and change characteristics maps of ERI obtained by using block Kriging were analyzed to reveal the spatial and temporal evolution characteristics,change rules and formation mechanisms of ecological risk based on land use under the background of urbanization,and to minimize land use risk during urbanization process. The results showed that during the past 18 years,moderate ecological risk level was major,while proportion of high ecological risk was the lowest,and the area of higher and lower ecological risk region changed most greatly; high and higher ecological risk were focused on urban region and the transition zone from urban to suburban region,while low and lower ecological risk mainly distributed in forestland with higher vegetation coverage,water bodies,grassland,shrub land and so on. Meanwhile,the transition zone from high to low ecological risk was very obvious. In addition,ecological risk became slightly worse in some region due to the transformation from cropland to residential and urban land,while it became slightly better in other regions because of the transformation from cropland to forestland; the center of gravity in lower ecological risk region shifted most greatly,while the shift was the smallest in high ecological risk region,namely 12. 31 and 0. 57 km respectively.
