The Institute of Aerospace Sciences of the Chinese Academy of Sciences released data revealing how Chinese cities have grown from small to large

　　How do Chinese cities grow from small to large

Chinese Academy of Sciences Institute of Aerospace Science released the extended remote sensing monitoring database for 75 typical cities in the past 50 years

　　Author: reporter Qi Fang

Our newspaper, Beijing, March 4 (Reporter Qi Fang)

With the development of the national economy, Chinese cities are gradually growing from small to large.

Is there a way for us to intuitively "see" how Chinese cities are expanding?

Remote sensing is possible. Recently, the land resources team led by researcher Zhang Zengxiang from the National Remote Sensing Application Engineering Technology Research Center of the Institute of Aerospace Information Innovation of the Chinese Academy of Sciences released a remote sensing monitoring database for typical cities in China from 1972 to 2020, reflecting the recent 50 years of Chinese cities Extended spatio-temporal change characteristics.

　　At present, the database includes the status quo and expansion trends of 75 typical cities including 4 municipalities directly under the Central Government, 28 provincial (capital) cities, 2 special administrative regions, and 41 other cities (including 5 cities under separate planning) from 1972 to 2020 Happening.

　　Zhang Zengxiang introduced that the land and resources team relies on remote sensing and geographic information systems to meet the needs of national economic construction and environmental protection. In the field of remote sensing of resources and environment across the country, the main content is land use, land cover, soil erosion, etc. A series of investigations, monitoring, analysis and evaluation studies have been carried out.

On this basis, the team has continued to carry out remote sensing monitoring research on China's urban expansion for nearly 40 years, and in 2006 took the lead in completing the long-term sequence of China's provincial capitals (capitals), municipalities and special administrative regions from the 1970s to 2005. , High-frequency urban expansion remote sensing monitoring. In 2014, the urban expansion remote sensing monitoring of 60 typical cities in China was completed from the 1970s to 2013. In 2016, the number of urban monitoring was increased to 75, and then realized The annual monitoring of the expansion of 75 typical cities in China was completed, and finally a remote sensing monitoring database for urban expansion from 1972 to 2020 was formed.

　　Based on these data, the research team analyzed the characteristics and laws of urban expansion in China.

For example, the research team analyzed the differences in urban expansion from multiple perspectives such as urban administrative level, population size, and regional distribution. In the past 50 years, China’s urban expansion has characteristics such as universality, stage, and volatility; urban expansion and major policy implementation and national The strategic deployment is time-aligned and can clearly reflect the impact of major national strategies such as "Western Development", "Rise of Central China", and "New Urbanization" on urban land use.

　　Research also suggests that the impact of urban expansion on food production should be taken seriously.

According to Zhang Zengxiang, the team studied the occupation of cultivated land by different types of urban expansion in different periods, and the results showed that urban expansion has caused continuous pressure on cultivated land protection.

The contribution rate of cultivated land to urban expansion fluctuated between 50% and 70% in different periods, but the overall proportion showed a decreasing trend, reflecting the effectiveness of the state’s policies on controlling the occupation of cultivated land for construction land; among cities of different sizes, huge cities (population >10 million) the highest proportion of cultivated land occupied by expansion, reaching 61.59%.