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1. This is the dataset described by the report "Global Urban Land Cover Changes in 2000-2020" submitted to Global Ecosystem and Environment Observation Analysis Research Cooperation (GEOARC). 2. The dataset includes the following subsets, i.e. global urban boundary (named as "GUB_Year_Continent.tif", like "GUB_2000_Africa.tif"), global urban green space fraction (named as "GUGS_Year_Continent.tif", like "GUGS_2000_Africa.tif"), global impervious surface area fraction (named as "GISA_Year_Continent.tif", like "GISA_2000_Africa.tif"),urban agglomeration urban boundaries and land cover changes,megacities urban boundaries and land cover changes.See the description document for details. 3. The global impervious surface area and global urban green space datasets are showed by the percentage in a grid. In order for data storage, the data were amplified by 100 times and converted into integer storage. 4. The detail information of datasets is listed in Description.xlsx 5. Some sample mapping were listed in Samples.zip. 6. If you have any questions, please contact Wenhui Kuang (kuangwh@igsnrr.ac.cn). 7.Related publications with this dataset. (1)Kuang W H, Du G M, Lu D S, et al. Global observation of urban expansion and land-cover dynamics using satellite big-data. Science Bulletin. 2021, 66(4): 297-300. (2)Kuang W H, Zhang S, Li X Y, et al. A 30 m resolution dataset of China’s urban impervious surface area and green space, 2000–2018. Earth System Science Data. 2021, 13(1): 63-82. (3) Kuang W H. 70 years of urban expansion across China: trajectory, pattern, and national policies. Science Bulletin. 2020, 65(23): 1970-7974. (4) Kuang W H, Dou Y Y. Investigating the patterns and dynamics of urban green space in China’s 70 major cities using satellite remote sensing. Remote Sensing. 2020, 12(12): 1929. (5) Kuang W H. National urban land-use cover change since the beginning of the 21st century and its policy implications in China. Land Use Policy. 2020, 97: 104747. (6) Kuang W H. Mapping global impervious surface area and green space within urban environments. Science China Earth Sciences. 2019, 62(10): 1591-1606. (7) Dou Y Y, Kuang W H. A comparative analysis of urban impervious surface and green space and their dynamics among 318 different size cities in China in the past 25 years. Science of the Total Environment. 2020, 706:135828. (8) Zhang S, Fang C L, Kuang W H, et al. Comparison of changes in urban land use/cover and efficiency of megaregions in China from 1980 to 2015. Remote Sensing. 2019, 11(15): 1834. (9) Pan T, Kuang W H, Zhang C, et al. City-level comparison of urban land-cover configurations from 2000-2015 across 65 countries within the global Belt and Road. Remote Sensing. 2019, 11(13): 1515., {"references":["Kuang W H, Du G M, Lu D S, et al. Global observation of urban expansion and land-cover dynamics using satellite big-data. Science Bulletin. 2021, 66(4): 297-300.","Kuang W H, Zhang S, Li X Y, et al. A 30 m resolution dataset of China's urban impervious surface area and green space, 2000–2018. Earth System Science Data. 2021, 13(1): 63-82.","Kuang W H. 70 years of urban expansion across China: trajectory, pattern, and national policies. Science Bulletin. 2020, 65(23): 1970-7974.","Kuang W H, Dou Y Y. Investigating the patterns and dynamics of urban green space in China's 70 major cities using satellite remote sensing. Remote Sensing. 2020, 12(12): 1929.","Kuang W H. National urban land-use cover change since the beginning of the 21st century and its policy implications in China. Land Use Policy. 2020, 97: 104747.","Kuang W H. Mapping global impervious surface area and green space within urban environments. Science China Earth Sciences. 2019, 62(10): 1591-1606.","Dou Y Y, Kuang W H. A comparative analysis of urban impervious surface and green space and their dynamics among 318 different size cities in China in the past 25 years. Science of the Total Environment. 2020, 706:135828.","Zhang S, Fang C L, Kuang W H, et al. Comparison of changes in urban land use/cover and efficiency of megaregions in China from 1980 to 2015. Remote Sensing. 2019, 11(15): 1834.","Pan T, Kuang W H, Zhang C, et al. City-level comparison of urban land-cover configurations from 2000-2015 across 65 countries within the global Belt and Road. Remote Sensing. 2019, 11(13): 1515."]}

The microstructure and oxidation behavior at high temperatures ranging from 900 °C to 1100 °C of equiatomic CrMoNbTaV high-entropy alloy produced by vacuum arc melting were investigated. The phase component, microstructure, and microhardness of the alloy were examined by using X-ray diffraction, scanning electron microscopy equipped with an energy-dispersive X-ray spectroscope, and Vickers hardness tests, respectively. The as-cast alloy consists of a single body-centered cubic (BCC) refractory metal solid solution due to the high mixing entropy effect and exhibits a dendritic microstructure. The alloy has a very high microhardness value of 923 HV due to the strong solid solution strengthening effect. The average microhardness in interdendrites (950 HV) was higher than that in dendrites (896 HV) because of composition segregation. The oxidation kinetic curves of the alloy after exposure to air at 900 and 1000 °C follow the pseudo-parabolic rate law, while the mass gain increases first and then decreases at 1100 °C. The thickness of the oxide layer increases with the increasing of oxidation time. The long rod-shaped oxidation products are composed of Nb2O5, NbO2, CrTaO4, CrNbO4, Ta9VO25, Nb9VO25, and TaO after oxidation at 900 and 1000 °C for 25 h. The oxides of CrTaO4 and CrNbO4 disappear as the oxidation temperature elevated to 1100 °C.

The dataset includes four subsets, i.e. urban boundary, urban green space fraction, urban impervious surface area fraction, urban waterbody. The urban impervious surface area and urban green space datasets are showed by the percentage in a grid. In order for data storage, the data were amplified by 1000 times and converted into integer storage. The urban waterbody datasets is showed by classification, where 1 refer to urban waterbody. If you have any questions, please contact Wenhui Kuang (kuangwh@igsnrr.ac.cn). Detailed information were listed in description.xlsx

Strategic transformation of regionalization for agricultural comprehensive development (ACD) was presented by the Ministry of Finance of the People’s Republic of China (MOF) in 2014. The regionalization is the premise and basis of the sustainable development and improved competitiveness for agriculture. Based on the environmental resources related to agriculture, such as cropland, climate, water resources, terrain, geomorphology, patterns of the ACD projects, distribution of ecological planning, etc., we devised 13 indices using the geographic comprehensive regionalization method. The indices took into account a combination of dynamic and static, qualitative and quantitative, as well as agricultural and ecological factors. The strategic transformation of regionalization for the ACD in Ningxia Hui Autonomous Region of China was performed; seven types were included: prioritized regions, prioritized and restricted regions, protected regions, protected and restricted regions, restricted and prioritized regions, restricted and protected regions, and restricted regions. A further 24 subtypes were used based on locations and ecological zones. The regionalization results showed that prioritized regions were mainly in northern Ningxia, the most suitable area for agriculture. The protected and restricted regions were in central and southern Ningxia. In the central part, drought was the limiting factor for agriculture, and water conservation projects there should be supported. The ecological environment is fragile in southern Ningxia, so there is a need for ecologically sound agriculture to be developed in this region. Such regionalization could achieve two goals, namely agricultural conservation and eco-environmental protection. It was performed following the requirement for scientific regionalization to include three types of regions (prioritized regions, protected regions, and restricted regions), and was applied at the township scale in a provincial or autonomous region for the first time. The results provide both guidance for the strategic transformation of the ACD in Ningxia, and a reference for similar work in other provinces.

In order to understand the effects of variation in consumption structure of bio-resource products on the ecological environment, in the case of Ordos City in Inner Mongolia, we explored ecological footprint (EF) based on sub-national (provincial) hectare, which was modified from global hectare, to analyze the characteristics of consumption structure of bio-resources and their ecological influence in 1995 and 2012 (before and after the project of “Return Grazing Land to Grassland”). The results showed that the consumption structure of bio-resource products tended towards multiplication in Ordos City. The food consumption transformed from mainly grain-oil and meat-milk-eggs to a variety of foods; in addition, the consumption of firewood was replaced by fossil fuels gradually. Compared with 1995, the EFs of grain-oil and firewood consumption were reduced by 53.23% and 86.49%, and the increase of melons-vegetables was 44.97% in 2012, respectively. The EF of bio-resource product consumption was mainly relied on cultivated land, which included grain-oils, melons-vegetables and meat-milk-eggs. The EFs of these productions consumption on cultivated land increased or decreased to different extents before and after the “Return Grazing Land to Grassland”. The contribution rate of grain-oils on cultivated land decreased from 40.17% (in 1995) to 21.74% (in 2012), while the contribution rates of melons-vegetables and meat-milk-eggs increased. The Ecological Deficit (ED) of Ordos City in 2012 reached 2.7384 hm2/cap lower than the ED in 1995 (3.4382 hm2/cap), and eco-efficiency in 2012 also was obviously higher than the level in 1995. This indicated that the disturbance and consumption of human activity on the natural resources, and their influences on ecological environment declined, and the utilization efficiency of resources and environment has been significantly improved. However, the ED rate was still very high due to the floating population; approximately 548.83×104 hm2 biological productive land area will be needed to satisfy the total population's demands of consumption of bio-resource products in Ordos City in 2012. The research demonstrated the transformation of consumption structure of bio-resources products has benefit to ease the ecological stress in Ordos City. Furthermore, the increasing of ecological efficiency will play a significant role in improving the human-land relationship, as well as the ecological environment.

Land use and land cover change as the core of coupled human-environment systems has become a potential field of land change science (LCS) in the study of global environmental change. Based on remotely sensed data of land use change with a spatial resolution of 1 km x 1 km on national scale among every 5 years, this paper designed a new dynamic regionalization according to the comprehensive characteristics of land use change including regional differentiation, physical, economic, and macro-policy factors as well. Spatial pattern of land use change and its driving forces were investigated in China in the early 21st century. To sum up, land use change pattern of this period was characterized by rapid changes in the whole country. Over the agricultural zones, e.g., Huang-Huai-Hai Plain, the southeast coastal areas and Sichuan Basin, a great proportion of fine arable land were engrossed owing to considerable expansion of the built-up and residential areas, resulting in decrease of paddy land area in southern China. The development of oasis agriculture in Northwest China and the reclamation in Northeast China led to a slight increase in arable land area in northern China. Due to the "Grain for Green" policy, forest area was significantly increased in the middle and western developing regions, where the vegetation coverage was substantially enlarged, likewise. This paper argued the main driving forces as the implementation of the strategy on land use and regional development, such as policies of "Western Development", "Revitalization of Northeast", coupled with rapidly economic development during this period.